diff options
| -rw-r--r-- | LICENSE | 13 | ||||
| -rw-r--r-- | spew/common.go | 241 | ||||
| -rw-r--r-- | spew/config.go | 57 | ||||
| -rw-r--r-- | spew/doc.go | 148 | ||||
| -rw-r--r-- | spew/dump.go | 323 | ||||
| -rw-r--r-- | spew/dump_test.go | 675 | ||||
| -rw-r--r-- | spew/example_test.go | 132 | ||||
| -rw-r--r-- | spew/format.go | 338 | ||||
| -rw-r--r-- | spew/spew.go | 115 |
9 files changed, 2042 insertions, 0 deletions
@@ -0,0 +1,13 @@ +Copyright (c) 2012-2013 Dave Collins <[email protected]> + +Permission to use, copy, modify, and distribute this software for any +purpose with or without fee is hereby granted, provided that the above +copyright notice and this permission notice appear in all copies. + +THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR +ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. diff --git a/spew/common.go b/spew/common.go new file mode 100644 index 0000000..69b95e4 --- /dev/null +++ b/spew/common.go @@ -0,0 +1,241 @@ +/* + * Copyright (c) 2013 Dave Collins <[email protected]> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +package spew + +import ( + "fmt" + "io" + "reflect" + "strconv" + "unsafe" +) + +// reflectValue mirrors the struct layout of the reflect package Value type. +var reflectValue struct { + typ unsafe.Pointer + val unsafe.Pointer + flag uintptr +} + +// flagIndir indicates whether the value field of a reflect.Value is the actual +// data or a pointer to the data. +const flagIndir = 1 << 1 + +// unsafeReflectValue converts the passed reflect.Value into a one that bypasses +// the typical safety restrictions preventing access to unaddressable and +// unexported data. It works by digging the raw pointer to the underlying +// value out of the protected value and generating a new unprotected (unsafe) +// reflect.Value to it. +// +// This allows us to check for implementations of the Stringer and error +// interfaces to be used for pretty printing ordinarily unaddressable and +// inaccessible values such as unexported struct fields. +func unsafeReflectValue(v reflect.Value) (rv reflect.Value) { + indirects := 1 + vt := v.Type() + upv := unsafe.Pointer(uintptr(unsafe.Pointer(&v)) + unsafe.Offsetof(reflectValue.val)) + rvf := *(*uintptr)(unsafe.Pointer(uintptr(unsafe.Pointer(&v)) + unsafe.Offsetof(reflectValue.flag))) + if rvf&flagIndir != 0 { + vt = reflect.PtrTo(v.Type()) + indirects++ + } + + pv := reflect.NewAt(vt, upv) + rv = pv + for i := 0; i < indirects; i++ { + rv = rv.Elem() + } + return rv +} + +// Some constants in the form of bytes to avoid string overhead. This mirrors +// the technique used in the fmt package. +var ( + panicBytes = []byte("(PANIC=") + plusBytes = []byte("+") + iBytes = []byte("i") + trueBytes = []byte("true") + falseBytes = []byte("false") + interfaceBytes = []byte("(interface {}) ") + commaNewlineBytes = []byte(",\n") + newlineBytes = []byte("\n") + openBraceBytes = []byte("{") + openBraceNewlineBytes = []byte("{\n") + closeBraceBytes = []byte("}") + closeBraceNewlinBytes = []byte("}\n") + asteriskBytes = []byte("*") + colonSpaceBytes = []byte(": ") + openParenBytes = []byte("(") + closeParenBytes = []byte(")") + spaceBytes = []byte(" ") + pointerChainBytes = []byte("->") + nilAngleBytes = []byte("<nil>") + maxNewlineBytes = []byte("<max depth reached>\n") + maxShortBytes = []byte("<max>") + circularBytes = []byte("<already shown>") + circularShortBytes = []byte("<shown>") + invalidAngleBytes = []byte("<invalid>") + percentBytes = []byte("%") + precisionBytes = []byte(".") + openAngleBytes = []byte("<") + closeAngleBytes = []byte(">") + openMapBytes = []byte("map[") + closeMapBytes = []byte("]") +) + +// hexDigits is used to map a decimal value to a hex digit. +var hexDigits = "0123456789abcdef" + +// unpackValue returns values inside of non-nil inteferfaces when possible. +// This is useful for data types like structs, arrays, slices, and maps which +// can contain varying types packed inside an interface. +func unpackValue(v reflect.Value) reflect.Value { + if v.Kind() == reflect.Interface && !v.IsNil() { + v = v.Elem() + } + return v +} + +// catchPanic handles any panics that might occur during the handleMethods +// calls. +func catchPanic(w io.Writer, v reflect.Value) { + if err := recover(); err != nil { + w.Write(panicBytes) + fmt.Fprintf(w, "%v", err) + w.Write(closeParenBytes) + } +} + +// handleMethods attempts to call the Error and String methods on the underlying +// type the passed reflect.Value represents and outputes the result to Writer w. +// +// It handles panics in any called methods by catching and displaying the error +// as the formatted value. +func handleMethods(w io.Writer, v reflect.Value) (handled bool) { + // We need an interface to check if the type implements the error or + // Stringer interface. However, the reflect package won't give us an + // an interface on certain things like unexported struct fields in order + // to enforce visibility rules. We use unsafe to bypass these restrictions + // since this package does not mutate the values. + if !v.CanInterface() { + v = unsafeReflectValue(v) + } + + // Choose whether or not to do error and Stringer interface lookups against + // the base type or a pointer to the base type depending on settings. + // Technically calling one of these methods with a pointer receiver can + // mutate the value, however, types which choose to satisify an error or + // Stringer interface with a pointer receiver should not be mutating their + // state inside these interface methods. + var viface interface{} + if !Config.DisablePointerMethods { + if !v.CanAddr() { + v = unsafeReflectValue(v) + } + viface = v.Addr().Interface() + } else { + viface = v.Interface() + } + + // Is it an error or Stringer? + switch iface := viface.(type) { + case error: + defer catchPanic(w, v) + w.Write([]byte(iface.Error())) + return true + + case fmt.Stringer: + defer catchPanic(w, v) + w.Write([]byte(iface.String())) + return true + } + return false +} + +// printBool outputs a boolean value as true or false to Writer w. +func printBool(w io.Writer, val bool) { + if val { + w.Write(trueBytes) + } else { + w.Write(falseBytes) + } +} + +// printInt outputs a signed integer value to Writer w. +func printInt(w io.Writer, val int64) { + w.Write([]byte(strconv.FormatInt(val, 10))) +} + +// printUint outputs an unsigned integer value to Writer w. +func printUint(w io.Writer, val uint64) { + w.Write([]byte(strconv.FormatUint(val, 10))) +} + +// printFloat outputs a floating point value using the specified precision, +// which is expected to be 32 or 64bit, to Writer w. +func printFloat(w io.Writer, val float64, precision int) { + w.Write([]byte(strconv.FormatFloat(val, 'g', -1, precision))) +} + +// printComplex outputs a complex value using the specified float precision +// for the real and imaginary parts to Writer w. +func printComplex(w io.Writer, c complex128, floatPrecision int) { + r := real(c) + w.Write(openParenBytes) + w.Write([]byte(strconv.FormatFloat(r, 'g', -1, floatPrecision))) + i := imag(c) + if i >= 0 { + w.Write(plusBytes) + } + w.Write([]byte(strconv.FormatFloat(i, 'g', -1, floatPrecision))) + w.Write(iBytes) + w.Write(closeParenBytes) +} + +// printHexPtr outputs a uintptr formatted as hexidecimal with a leading '0x' +// prefix to Writer w. +func printHexPtr(w io.Writer, p uintptr) { + // Null pointer. + num := uint64(p) + if num == 0 { + w.Write(nilAngleBytes) + return + } + + // Max uint64 is 16 bytes in hex + 2 bytes for '0x' prefix + buf := make([]byte, 18) + + // It's simpler to construct the hex string right to left. + base := uint64(16) + i := len(buf) - 1 + for num >= base { + buf[i] = hexDigits[num%base] + num /= base + i-- + } + buf[i] = hexDigits[num] + + // Add '0x' prefix. + i-- + buf[i] = 'x' + i-- + buf[i] = '0' + + // Strip unused leading bytes. + buf = buf[i:] + w.Write(buf) +} diff --git a/spew/config.go b/spew/config.go new file mode 100644 index 0000000..542f457 --- /dev/null +++ b/spew/config.go @@ -0,0 +1,57 @@ +/* + * Copyright (c) 2013 Dave Collins <[email protected]> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +package spew + +// ConfigState is used to describe configuration options used by spew to format +// and display values. There is currently only a single global instance, Config, +// that is used to control all Formatter and Dump functionality. This state +// is designed so that it would be fairly simple to add the ability to have +// unique config per Formatter or dumpState instance if there is demand for +// such a feature. +type ConfigState struct { + // MaxDepth controls the maximum number of levels to descend into nested + // data structures. The default, 0, means there is no limit. + // + // NOTE: Circular data structures are properly detected, so it is not + // necessary to set this value unless you specifically want to limit deeply + // nested data structures. + MaxDepth int + + // Indent specifies the string to use for each indentation level. It is + // a single space by default. If you would like more indentation, you might + // set this to a tab with "\t" or perhaps two spaces with " ". + Indent string + + // DisableMethods specifies whether or not error and Stringer interfaces are + // invoked for types that implement them. + DisableMethods bool + + // DisablePointerMethods specifies whether or not to check for and invoke + // error and Stringer interfaces on types which only accept a pointer + // receiver when the current type is not a pointer. + // + // NOTE: This might be an unsafe action since calling one of these methods + // with a pointer receiver could technically mutate the value, however, + // in practice, types which choose to satisify an error or Stringer + // interface with a pointer receiver should not be mutating their state + // inside these interface methods. + DisablePointerMethods bool +} + +// Config is the active configuration in use by spew. The configuration +// can be changed by modifying the contents of spew.Config. +var Config ConfigState = ConfigState{Indent: " "} diff --git a/spew/doc.go b/spew/doc.go new file mode 100644 index 0000000..06278f3 --- /dev/null +++ b/spew/doc.go @@ -0,0 +1,148 @@ +/* + * Copyright (c) 2013 Dave Collins <[email protected]> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +/* +Package spew implements a deep pretty printer for Go data structures to aid in +debugging. + +A quick overview of the additional features spew provides over the built-in +printing facilities for Go data types are as follows: + + * Pointers are dereferenced and followed + * Circular data structures are detected and handled properly + * Custom error/Stringer interfaces are optionally invoked, including + on unexported types + * Custom types which only implement the error/Stringer interfaces via + a pointer receiver are optionally invoked when passing non-pointer + variables + +There are two different approaches spew allows for dumping Go data structures: + + * Dump style which prints with newlines, customizable indentation, + and additional debug information such as types and all pointer addresses + used to indirect to the final value + * A custom Formatter interface that integrates cleanly with the standard fmt + package and replaces %v and %+v to provide inline printing similar + to the default %v while providing the additional functionality outlined + above and passing unsupported format verb/flag combinations such a %x, + %q, and %#v along to fmt + +Quick Start + +This section demonstrates how to quickly get started with spew. See the +sections below for further details on formatting and configuration options. + +To dump a variable with full newlines, indentation, type, and pointer +information use Dump or Fdump: + spew.Dump(myVar1, myVar2, ...) + spew.Fdump(someWriter, myVar1, myVar2, ...) + +Alternatively, if you would prefer to use format strings with a compacted inline +printing style, use the convenience wrappers Printf, Fprintf, etc with either +%v (most compact) or %+v (adds pointer addresses): + spew.Printf("myVar1: %v -- myVar2: %+v", myVar1, myVar2) + spew.Fprintf(someWriter, "myVar1: %v -- myVar2: %+v", myVar1, myVar2) + +Configuration Options + +The following configuration options are available: + spew.Config.MaxDepth + Maximum number of levels to descend into nested data structures. + There is no limit by default. + + spew.Config.Indent + String to use for each indentation level for Dump functions. + It is a single space by default. A popular alternative is "\t". + + spew.Config.DisableMethods + Disables invocation of error and Stringer interface methods. + Method invocation is enabled by default. + + spew.Config.DisablePointerMethods + Disables invocation of error and Stringer interface methods on types + which only accept pointer receivers from non-pointer variables. + Pointer method invocation is enabled by default. + +Dump Usage + +Simply call spew.Dump with a list of variables you want to dump: + + spew.Dump(myVar1, myVar2, ...) + +You may also call spew.Fdump if you would prefer to output to an arbitrary +io.Writer. For example, to dump to standard error: + + spew.Fdump(os.Stderr, myVar1, myVar2, ...) + +Sample Dump Output + +See the Dump example for details on the setup of the types and variables being +shown here. + + (main.Foo) { + unexportedField: (*main.Bar)(0xf84002e210)({ + flag: (main.Flag) flagTwo, + data: (uintptr) <nil> + }), + ExportedField: (map[interface {}]interface {}) { + (string) "one": (bool) true + } + } + +Custom Formatter + +Spew provides a custom formatter the implements the fmt.Formatter interface +so that integrates cleanly with standard fmt package printing functions. The +formatter is useful for inline printing of smaller data types similar to the +standard %v format specifier. + +The spew formatter only responds to the %v and %+v verb combinations. Any other +variations such as %x, %q, and %#v will be sent to the the standard fmt package +for formatting. In addition, the spew formatter ignores the width and precision +arguments (however they will still work on the format specifiers spew does not +handle). + +Custom Formatter Usage + +The simplest way to make use of the spew custom formatter is to call one of the +convenience functions such as spew.Printf, spew.Println, or spew.Printf. The +functions have the exact same syntax you are most likely already familiar with: + + spew.Printf("myVar1: %v -- myVar2: %+v", myVar1, myVar2) + spew.Println(myVar, myVar2) + spew.Fprintf(os.Stderr, "myVar1: %v -- myVar2: %+v", myVar1, myVar2) + +See the Index for the full list convenience functions. + +Sample Formatter Output + +Double pointer to a uint8 via %v: + <**>5 + +Circular struct with a uint8 field and a pointer to itself via %+v: + {ui8:1 c:<*>(0xf84002d200){ui8:1 c:<*>(0xf84002d200)<shown>}} + +See the Printf example for details on the setup of variables being shown +here. + +Errors + +Since it is possible for custom error/Stringer interfaces to panic, spew +detects them and handles them internally by printing the panic information +inline with the output. Since spew is intended to provide deep pretty printing +capabilities on structures, it intentionally does not return any errors. +*/ +package spew diff --git a/spew/dump.go b/spew/dump.go new file mode 100644 index 0000000..7b5d87c --- /dev/null +++ b/spew/dump.go @@ -0,0 +1,323 @@ +/* + * Copyright (c) 2013 Dave Collins <[email protected]> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +package spew + +import ( + "bytes" + "fmt" + "io" + "os" + "reflect" + "strconv" +) + +// dumpState contains information about the state of a dump operation. +type dumpState struct { + w io.Writer + depth int + pointers map[uintptr]int + ignoreNextType bool + ignoreNextPad bool +} + +// pad performs indentation according to the depth level and Config.Indent +// option. +func (d *dumpState) pad() { + if d.ignoreNextPad { + d.ignoreNextPad = false + return + } + d.w.Write(bytes.Repeat([]byte(Config.Indent), d.depth)) +} + +// dumpPtr handles formatting of pointers by indirecting them as necessary. +func (d *dumpState) dumpPtr(v reflect.Value) { + // Remove pointers at or below the current depth from map used to detect + // circular refs. + for k, depth := range d.pointers { + if depth >= d.depth { + delete(d.pointers, k) + } + } + + // Keep list of all dereferenced pointers to show later. + pointerChain := make([]uintptr, 0) + + // Figure out how many levels of indirection there are by derferencing + // pointers and unpacking interfaces down the chain while detecting circular + // references. + nilFound := false + cycleFound := false + indirects := 0 + ve := v + for ve.Kind() == reflect.Ptr { + indirects++ + if ve.IsNil() { + nilFound = true + break + } + addr := ve.Pointer() + pointerChain = append(pointerChain, addr) + if pd, ok := d.pointers[addr]; ok && pd < d.depth { + cycleFound = true + indirects-- + break + } + d.pointers[addr] = d.depth + + ve = ve.Elem() + if ve.Kind() == reflect.Interface { + if ve.IsNil() { + nilFound = true + break + } + ve = ve.Elem() + } + } + + // Display type information. + d.w.Write(openParenBytes) + d.w.Write(bytes.Repeat(asteriskBytes, indirects)) + d.w.Write([]byte(ve.Type().String())) + d.w.Write(closeParenBytes) + + // Display pointer information. + d.w.Write(openParenBytes) + for i, addr := range pointerChain { + if i > 0 { + d.w.Write(pointerChainBytes) + } + printHexPtr(d.w, addr) + } + d.w.Write(closeParenBytes) + + // Display dereferenced value. + d.w.Write(openParenBytes) + switch { + case nilFound == true: + d.w.Write(nilAngleBytes) + + case cycleFound == true: + d.w.Write(circularBytes) + + default: + d.ignoreNextType = true + d.dump(ve) + } + d.w.Write(closeParenBytes) +} + +// dump is the main workhorse for dumping a value. It uses the passed reflect +// value to figure out what kind of object we are dealing with and formats it +// appropriately. It is a recursive function, however circular data structures +// are detected and handled properly. +func (d *dumpState) dump(v reflect.Value) { + // Handle pointers specially. + kind := v.Kind() + if kind == reflect.Ptr { + d.pad() + d.dumpPtr(v) + return + } + + // Print type information unless already handled elsewhere. + if !d.ignoreNextType { + d.pad() + d.w.Write(openParenBytes) + d.w.Write([]byte(v.Type().String())) + d.w.Write(closeParenBytes) + d.w.Write(spaceBytes) + } + d.ignoreNextType = false + + // Call error/Stringer interfaces if they exist and the handle methods flag + // is enabled + if !Config.DisableMethods { + if (kind != reflect.Invalid) && (kind != reflect.Interface) { + if handled := handleMethods(d.w, v); handled { + return + } + } + } + + switch kind { + case reflect.Invalid: + d.w.Write(invalidAngleBytes) + + case reflect.Bool: + printBool(d.w, v.Bool()) + + case reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int: + printInt(d.w, v.Int()) + + case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint: + printUint(d.w, v.Uint()) + + case reflect.Float32: + printFloat(d.w, v.Float(), 32) + + case reflect.Float64: + printFloat(d.w, v.Float(), 64) + + case reflect.Complex64: + printComplex(d.w, v.Complex(), 32) + + case reflect.Complex128: + printComplex(d.w, v.Complex(), 64) + + case reflect.Array, reflect.Slice: + d.w.Write(openBraceNewlineBytes) + d.depth++ + if (Config.MaxDepth != 0) && (d.depth > Config.MaxDepth) { + d.pad() + d.w.Write(maxNewlineBytes) + } else { + numEntries := v.Len() + for i := 0; i < numEntries; i++ { + d.dump(unpackValue(v.Index(i))) + if i < (numEntries - 1) { + d.w.Write(commaNewlineBytes) + } else { + d.w.Write(newlineBytes) + } + } + } + d.depth-- + d.pad() + d.w.Write(closeBraceBytes) + + case reflect.String: + d.w.Write([]byte(strconv.Quote(v.String()))) + + case reflect.Interface: + // Do nothing. We should never get here due to unpackValue calls. + + case reflect.Ptr: + // Do nothing. We should never get here since pointer have already + // been handled above. + + case reflect.Map: + d.w.Write(openBraceNewlineBytes) + d.depth++ + if (Config.MaxDepth != 0) && (d.depth > Config.MaxDepth) { + d.pad() + d.w.Write(maxNewlineBytes) + } else { + numEntries := v.Len() + keys := v.MapKeys() + for i, key := range keys { + d.dump(unpackValue(key)) + d.w.Write(colonSpaceBytes) + d.ignoreNextPad = true + d.dump(unpackValue(v.MapIndex(key))) + if i < (numEntries - 1) { + d.w.Write(commaNewlineBytes) + } else { + d.w.Write(newlineBytes) + } + } + } + d.depth-- + d.pad() + d.w.Write(closeBraceBytes) + + case reflect.Struct: + d.w.Write(openBraceNewlineBytes) + d.depth++ + if (Config.MaxDepth != 0) && (d.depth > Config.MaxDepth) { + d.pad() + d.w.Write(maxNewlineBytes) + } else { + vt := v.Type() + numFields := v.NumField() + for i := 0; i < numFields; i++ { + d.pad() + vtf := vt.Field(i) + d.w.Write([]byte(vtf.Name)) + d.w.Write(colonSpaceBytes) + d.ignoreNextPad = true + d.dump(unpackValue(v.Field(i))) + if i < (numFields - 1) { + d.w.Write(commaNewlineBytes) + } else { + d.w.Write(newlineBytes) + } + } + } + d.depth-- + d.pad() + d.w.Write(closeBraceBytes) + + case reflect.Uintptr: + printHexPtr(d.w, uintptr(v.Uint())) + + case reflect.UnsafePointer, reflect.Chan, reflect.Func: + printHexPtr(d.w, v.Pointer()) + + // There were not any other types at the time this code was written, but + // fall back to letting the default fmt package handle it in case any new + // types are added. + default: + if v.CanInterface() { + fmt.Fprintf(d.w, "%v", v.Interface()) + } else { + fmt.Fprintf(d.w, "%v", v.String()) + } + } +} + +// Fdump formats and displays the passed arguments to io.Writer w. It formats +// exactly the same as Dump.
+func Fdump(w io.Writer, a ...interface{}) { + for _, arg := range a { + if arg == nil { + w.Write(interfaceBytes) + w.Write(nilAngleBytes) + w.Write(newlineBytes) + continue + } + + d := dumpState{w: w} + d.pointers = make(map[uintptr]int) + d.dump(reflect.ValueOf(arg)) + d.w.Write(newlineBytes) + } +} + +/* +Dump displays the passed parameters to standard out with newlines, customizable +indentation, and additional debug information such as complete types and all +pointer addresses used to indirect to the final value. It provides the +following features over the built-in printing facilities provided by the fmt +package: + + * Pointers are dereferenced and followed + * Circular data structures are detected and handled properly + * Custom error/Stringer interfaces are optionally invoked, including + on unexported types + * Custom types which only implement the error/Stringer interfaces via + a pointer receiver are optionally invoked when passing non-pointer + variables + +The configuration options are controlled by an exported package global, +spew.Config. See ConfigState for options documentation. + +See Fdump if you would prefer dump to an arbitrary io.Writer. +*/ +func Dump(a ...interface{}) { + Fdump(os.Stdout, a...) +} diff --git a/spew/dump_test.go b/spew/dump_test.go new file mode 100644 index 0000000..a9504a8 --- /dev/null +++ b/spew/dump_test.go @@ -0,0 +1,675 @@ +/* + * Copyright (c) 2013 Dave Collins <[email protected]> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +/* +Test Summary: +NOTE: For each test, a pointer and double pointer to the base test element +are also tested to ensure proper indirection across all types. + +- Max int8, int16, int32, int64, int +- Max uint8, uint16, uint32, uint64, uint +- Boolean true and false +- Standard complex64 and complex128 +- Array containing standard ints +- Array containing type with custom formatter on pointer receiver only +- Slice containing standard float32 values +- Slice containing type with custom formatter on pointer receiver only +- Standard string +- Nil interface +- Map with string keys and int vals +- Map with custom formatter type on pointer receiver only keys and vals +- Map with interface keys and values +- Struct with primitives +- Struct that contains another struct +- Struct that contains custom type with Stringer pointer interface via both + exported and unexported fields +- Uintptr to 0 (null pointer) +- Uintptr address of real variable +- Unsafe.Pointer to 0 (null pointer) +- Unsafe.Pointer to address of real variable +- Nil channel +- Standard int channel +- Function with no params and no returns +- Function with param and no returns +- Function with multiple params and multiple returns +- Struct that is circular through self referencing +- Structs that are circular through cross referencing +- Structs that are indirectly circular +*/ + +package spew_test + +import ( + "bytes" + "fmt" + "github.com/davecgh/go-spew/spew" + "testing" + "unsafe" +) + +// custom type to test Stinger interface on pointer receiver. +type pstringer string + +// String implements the Stringer interface for testing invocation of custom +// stringers on types with only pointer receivers. +func (s *pstringer) String() string { + return "stringer " + string(*s) +} + +// xref1 and xref2 are cross referencing structs for testing circular reference +// detection. +type xref1 struct { + ps2 *xref2 +} +type xref2 struct { + ps1 *xref1 +} + +// indirCir1, indirCir2, and indirCir3 are used to generate an indirect circular +// reference for testing detection. +type indirCir1 struct { + ps2 *indirCir2 +} +type indirCir2 struct { + ps3 *indirCir3 +} +type indirCir3 struct { + ps1 *indirCir1 +} + +// dumpTest is used to describe a test to be perfomed against the Dump method. +type dumpTest struct { + in interface{} + want string +} + +// dumpTests houses all of the tests to be performed against the Dump method. +var dumpTests = make([]dumpTest, 0) + +// addDumpTest is a helper method to append the passed input and desired result +// to dumpTests +func addDumpTest(in interface{}, want string) { + test := dumpTest{in, want} + dumpTests = append(dumpTests, test) +} + +func addIntTests() { + // Max int8. + v := int8(127) + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "int8" + vs := "127" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Max int16. + v2 := int16(32767) + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "int16" + v2s := "32767" + addDumpTest(v2, "("+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") + + // Max int32. + v3 := int32(2147483647) + pv3 := &v3 + v3Addr := fmt.Sprintf("%p", pv3) + pv3Addr := fmt.Sprintf("%p", &pv3) + v3t := "int32" + v3s := "2147483647" + addDumpTest(v3, "("+v3t+") "+v3s+"\n") + addDumpTest(pv3, "(*"+v3t+")("+v3Addr+")("+v3s+")\n") + addDumpTest(&pv3, "(**"+v3t+")("+pv3Addr+"->"+v3Addr+")("+v3s+")\n") + + // Max int64. + v4 := int64(9223372036854775807) + pv4 := &v4 + v4Addr := fmt.Sprintf("%p", pv4) + pv4Addr := fmt.Sprintf("%p", &pv4) + v4t := "int64" + v4s := "9223372036854775807" + addDumpTest(v4, "("+v4t+") "+v4s+"\n") + addDumpTest(pv4, "(*"+v4t+")("+v4Addr+")("+v4s+")\n") + addDumpTest(&pv4, "(**"+v4t+")("+pv4Addr+"->"+v4Addr+")("+v4s+")\n") + + // Max int. + v5 := int(2147483647) + pv5 := &v5 + v5Addr := fmt.Sprintf("%p", pv5) + pv5Addr := fmt.Sprintf("%p", &pv5) + v5t := "int" + v5s := "2147483647" + addDumpTest(v5, "("+v5t+") "+v5s+"\n") + addDumpTest(pv5, "(*"+v5t+")("+v5Addr+")("+v5s+")\n") + addDumpTest(&pv5, "(**"+v5t+")("+pv5Addr+"->"+v5Addr+")("+v5s+")\n") +} + +func addUintTests() { + // Max uint8. + v := uint8(255) + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "uint8" + vs := "255" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Max uint16. + v2 := uint16(65535) + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "uint16" + v2s := "65535" + addDumpTest(v2, "("+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") + + // Max uint32. + v3 := uint32(4294967295) + pv3 := &v3 + v3Addr := fmt.Sprintf("%p", pv3) + pv3Addr := fmt.Sprintf("%p", &pv3) + v3t := "uint32" + v3s := "4294967295" + addDumpTest(v3, "("+v3t+") "+v3s+"\n") + addDumpTest(pv3, "(*"+v3t+")("+v3Addr+")("+v3s+")\n") + addDumpTest(&pv3, "(**"+v3t+")("+pv3Addr+"->"+v3Addr+")("+v3s+")\n") + + // Max uint64. + v4 := uint64(18446744073709551615) + pv4 := &v4 + v4Addr := fmt.Sprintf("%p", pv4) + pv4Addr := fmt.Sprintf("%p", &pv4) + v4t := "uint64" + v4s := "18446744073709551615" + addDumpTest(v4, "("+v4t+") "+v4s+"\n") + addDumpTest(pv4, "(*"+v4t+")("+v4Addr+")("+v4s+")\n") + addDumpTest(&pv4, "(**"+v4t+")("+pv4Addr+"->"+v4Addr+")("+v4s+")\n") + + // Max uint. + v5 := uint(4294967295) + pv5 := &v5 + v5Addr := fmt.Sprintf("%p", pv5) + pv5Addr := fmt.Sprintf("%p", &pv5) + v5t := "uint" + v5s := "4294967295" + addDumpTest(v5, "("+v5t+") "+v5s+"\n") + addDumpTest(pv5, "(*"+v5t+")("+v5Addr+")("+v5s+")\n") + addDumpTest(&pv5, "(**"+v5t+")("+pv5Addr+"->"+v5Addr+")("+v5s+")\n") +} + +func addBoolTests() { + // Boolean true. + v := bool(true) + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "bool" + vs := "true" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Boolean false. + v2 := bool(false) + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "bool" + v2s := "false" + addDumpTest(v2, "("+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") +} + +func addFloatTests() { + // Standard float32. + v := float32(3.1415) + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "float32" + vs := "3.1415" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Standard float64. + v2 := float64(3.1415926) + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "float64" + v2s := "3.1415926" + addDumpTest(v2, "("+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") +} + +func addComplexTests() { + // Standard complex64. + v := complex(float32(6), -2) + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "complex64" + vs := "(6-2i)" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Standard complex128. + v2 := complex(float64(-6), 2) + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "complex128" + v2s := "(-6+2i)" + addDumpTest(v2, "("+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") +} + +func addArrayTests() { + // Array containing standard ints. + v := [3]int{1, 2, 3} + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "int" + vs := "{\n (" + vt + ") 1,\n (" + vt + ") 2,\n (" + vt + ") 3\n}" + addDumpTest(v, "([3]"+vt+") "+vs+"\n") + addDumpTest(pv, "(*[3]"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**[3]"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Array containing type with custom formatter on pointer receiver only. + v2 := [3]pstringer{"1", "2", "3"} + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "spew_test.pstringer" + v2s := "{\n (" + v2t + ") stringer 1,\n (" + v2t + ") stringer 2,\n (" + + v2t + ") stringer 3\n}" + addDumpTest(v2, "([3]"+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*[3]"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**[3]"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") +} + +func addSliceTests() { + // Slice containing standard float32 values. + v := []float32{3.14, 6.28, 12.56} + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "float32" + vs := "{\n (" + vt + ") 3.14,\n (" + vt + ") 6.28,\n (" + vt + ") 12.56\n}" + addDumpTest(v, "([]"+vt+") "+vs+"\n") + addDumpTest(pv, "(*[]"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**[]"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Slice containing type with custom formatter on pointer receiver only. + v2 := []pstringer{"1", "2", "3"} + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "spew_test.pstringer" + v2s := "{\n (" + v2t + ") stringer 1,\n (" + v2t + ") stringer 2,\n (" + + v2t + ") stringer 3\n}" + addDumpTest(v2, "([]"+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*[]"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**[]"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") +} + +func addStringTests() { + // Standard string. + v := "test" + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "string" + vs := "\"test\"" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") +} + +func addNilInterfaceTests() { + // Nil interface. + var v interface{} + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "interface {}" + vs := "<nil>" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") +} + +func addMapTests() { + // Map with string keys and int vals. + v := map[string]int{"one": 1} + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "map[string]int" + vt1 := "string" + vt2 := "int" + vs := "{\n (" + vt1 + ") \"one\": (" + vt2 + ") 1\n}" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Map with custom formatter type on pointer receiver only keys and vals. + v2 := map[pstringer]pstringer{"one": "1"} + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "map[spew_test.pstringer]spew_test.pstringer" + v2t1 := "spew_test.pstringer" + v2t2 := "spew_test.pstringer" + v2s := "{\n (" + v2t1 + ") stringer one: (" + v2t2 + ") stringer 1\n}" + addDumpTest(v2, "("+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") + + // Map with interface keys and values. + v3 := map[interface{}]interface{}{"one": 1} + pv3 := &v3 + v3Addr := fmt.Sprintf("%p", pv3) + pv3Addr := fmt.Sprintf("%p", &pv3) + v3t := "map[interface {}]interface {}" + v3t1 := "string" + v3t2 := "int" + v3s := "{\n (" + v3t1 + ") \"one\": (" + v3t2 + ") 1\n}" + addDumpTest(v3, "("+v3t+") "+v3s+"\n") + addDumpTest(pv3, "(*"+v3t+")("+v3Addr+")("+v3s+")\n") + addDumpTest(&pv3, "(**"+v3t+")("+pv3Addr+"->"+v3Addr+")("+v3s+")\n") +} + +func addStructTests() { + // Struct with primitives. + type s1 struct { + a int8 + b uint8 + } + v := s1{127, 255} + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "spew_test.s1" + vt2 := "int8" + vt3 := "uint8" + vs := "{\n a: (" + vt2 + ") 127,\n b: (" + vt3 + ") 255\n}" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Struct that contains another struct. + type s2 struct { + s1 s1 + b bool + } + v2 := s2{s1{127, 255}, true} + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "spew_test.s2" + v2t2 := "spew_test.s1" + v2t3 := "int8" + v2t4 := "uint8" + v2t5 := "bool" + v2s := "{\n s1: (" + v2t2 + ") {\n a: (" + v2t3 + ") 127,\n b: (" + + v2t4 + ") 255\n },\n b: (" + v2t5 + ") true\n}" + addDumpTest(v2, "("+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") + + // Struct that contains custom type with Stringer pointer interface via both + // exported and unexported fields. + type s3 struct { + s pstringer + S pstringer + } + v3 := s3{"test", "test2"} + pv3 := &v3 + v3Addr := fmt.Sprintf("%p", pv3) + pv3Addr := fmt.Sprintf("%p", &pv3) + v3t := "spew_test.s3" + v3t2 := "spew_test.pstringer" + v3s := "{\n s: (" + v3t2 + ") stringer test,\n S: (" + v3t2 + + ") stringer test2\n}" + addDumpTest(v3, "("+v3t+") "+v3s+"\n") + addDumpTest(pv3, "(*"+v3t+")("+v3Addr+")("+v3s+")\n") + addDumpTest(&pv3, "(**"+v3t+")("+pv3Addr+"->"+v3Addr+")("+v3s+")\n") +} + +func addUintptrTests() { + // Null pointer. + v := uintptr(0) + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "uintptr" + vs := "<nil>" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Address of real variable. + i := 1 + v2 := uintptr(unsafe.Pointer(&i)) + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "uintptr" + v2s := fmt.Sprintf("%p", &i) + addDumpTest(v2, "("+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") +} + +func addUnsafePointerTests() { + // Null pointer. + v := unsafe.Pointer(uintptr(0)) + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "unsafe.Pointer" + vs := "<nil>" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Address of real variable. + i := 1 + v2 := unsafe.Pointer(&i) + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "unsafe.Pointer" + v2s := fmt.Sprintf("%p", &i) + addDumpTest(v2, "("+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") +} + +func addChanTests() { + // Nil channel. + var v chan int + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "chan int" + vs := "<nil>" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Real channel. + v2 := make(chan int) + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "chan int" + v2s := fmt.Sprintf("%p", v2) + addDumpTest(v2, "("+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") +} + +func addFuncTests() { + // Function with no params and no returns. + v := addIntTests + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "func()" + vs := fmt.Sprintf("%p", v) + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n") + + // Function with param and no returns. + v2 := TestDump + pv2 := &v2 + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "func(*testing.T)" + v2s := fmt.Sprintf("%p", v2) + addDumpTest(v2, "("+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s+")\n") + addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n") + + // Function with multiple params and multiple returns. + var v3 = func(i int, s string) (b bool, err error) { + return true, nil + } + pv3 := &v3 + v3Addr := fmt.Sprintf("%p", pv3) + pv3Addr := fmt.Sprintf("%p", &pv3) + v3t := "func(int, string) (bool, error)" + v3s := fmt.Sprintf("%p", v3) + addDumpTest(v3, "("+v3t+") "+v3s+"\n") + addDumpTest(pv3, "(*"+v3t+")("+v3Addr+")("+v3s+")\n") + addDumpTest(&pv3, "(**"+v3t+")("+pv3Addr+"->"+v3Addr+")("+v3s+")\n") +} + +func addCircularTests() { + // Struct that is circular through self referencing. + type circular struct { + c *circular + } + v := circular{nil} + v.c = &v + pv := &v + vAddr := fmt.Sprintf("%p", pv) + pvAddr := fmt.Sprintf("%p", &pv) + vt := "spew_test.circular" + vs := "{\n c: (*" + vt + ")(" + vAddr + ")({\n c: (*" + vt + ")(" + + vAddr + ")(<already shown>)\n })\n}" + vs2 := "{\n c: (*" + vt + ")(" + vAddr + ")(<already shown>)\n}" + addDumpTest(v, "("+vt+") "+vs+"\n") + addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs2+")\n") + addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs2+")\n") + + // Structs that are circular through cross referencing. + v2 := xref1{nil} + ts2 := xref2{&v2} + v2.ps2 = &ts2 + pv2 := &v2 + ts2Addr := fmt.Sprintf("%p", &ts2) + v2Addr := fmt.Sprintf("%p", pv2) + pv2Addr := fmt.Sprintf("%p", &pv2) + v2t := "spew_test.xref1" + v2t2 := "spew_test.xref2" + v2s := "{\n ps2: (*" + v2t2 + ")(" + ts2Addr + ")({\n ps1: (*" + v2t + + ")(" + v2Addr + ")({\n ps2: (*" + v2t2 + ")(" + ts2Addr + + ")(<already shown>)\n })\n })\n}" + v2s2 := "{\n ps2: (*" + v2t2 + ")(" + ts2Addr + ")({\n ps1: (*" + v2t + + ")(" + v2Addr + ")(<already shown>)\n })\n}" + addDumpTest(v2, "("+v2t+") "+v2s+"\n") + addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s2+")\n") + addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s2+")\n") + + // Structs that are indirectly circular. + v3 := indirCir1{nil} + tic2 := indirCir2{nil} + tic3 := indirCir3{&v3} + tic2.ps3 = &tic3 + v3.ps2 = &tic2 + pv3 := &v3 + tic2Addr := fmt.Sprintf("%p", &tic2) + tic3Addr := fmt.Sprintf("%p", &tic3) + v3Addr := fmt.Sprintf("%p", pv3) + pv3Addr := fmt.Sprintf("%p", &pv3) + v3t := "spew_test.indirCir1" + v3t2 := "spew_test.indirCir2" + v3t3 := "spew_test.indirCir3" + v3s := "{\n ps2: (*" + v3t2 + ")(" + tic2Addr + ")({\n ps3: (*" + v3t3 + + ")(" + tic3Addr + ")({\n ps1: (*" + v3t + ")(" + v3Addr + + ")({\n ps2: (*" + v3t2 + ")(" + tic2Addr + + ")(<already shown>)\n })\n })\n })\n}" + v3s2 := "{\n ps2: (*" + v3t2 + ")(" + tic2Addr + ")({\n ps3: (*" + v3t3 + + ")(" + tic3Addr + ")({\n ps1: (*" + v3t + ")(" + v3Addr + + ")(<already shown>)\n })\n })\n}" + addDumpTest(v3, "("+v3t+") "+v3s+"\n") + addDumpTest(pv3, "(*"+v3t+")("+v3Addr+")("+v3s2+")\n") + addDumpTest(&pv3, "(**"+v3t+")("+pv3Addr+"->"+v3Addr+")("+v3s2+")\n") +} + +// TestDump executes all of the tests described by dumpTests. +func TestDump(t *testing.T) { + t.Logf("Running %d tests", len(dumpTests)) + for i, test := range dumpTests { + buf := new(bytes.Buffer) + spew.Fdump(buf, test.in) + s := buf.String() + if test.want != buf.String() { + t.Errorf("Dump #%d\n got: %s want: %s", i, s, test.want) + continue + } + } +} + +// Setup tests.f +func init() { + addIntTests() + addUintTests() + addBoolTests() + addFloatTests() + addComplexTests() + addArrayTests() + addSliceTests() + addStringTests() + addNilInterfaceTests() + addMapTests() + addStructTests() + addUintptrTests() + addUnsafePointerTests() + addChanTests() + addFuncTests() + addCircularTests() +} diff --git a/spew/example_test.go b/spew/example_test.go new file mode 100644 index 0000000..e96d2c1 --- /dev/null +++ b/spew/example_test.go @@ -0,0 +1,132 @@ +/* + * Copyright (c) 2013 Dave Collins <[email protected]> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +package spew_test + +import ( + "fmt" + "github.com/davecgh/go-spew/spew" +) + +type Flag int + +const ( + flagOne Flag = iota + flagTwo +) + +var flagStrings = map[Flag]string{ + flagOne: "flagOne", + flagTwo: "flagTwo", +} + +func (f Flag) String() string { + if s, ok := flagStrings[f]; ok { + return s + } + return fmt.Sprintf("Unknown flag (%d)", int(f)) +} + +type Bar struct { + flag Flag + data uintptr +} + +type Foo struct { + unexportedField Bar + ExportedField map[interface{}]interface{} +} + +// This example demonstrates how to use Dump to dump variables to stdout. +func ExampleDump() { + // The following package level declarations are assumed for this example: + /* + type Flag int + + const ( + flagOne Flag = iota + flagTwo + ) + + var flagStrings = map[Flag]string{ + flagOne: "flagOne", + flagTwo: "flagTwo", + } + + func (f Flag) String() string { + if s, ok := flagStrings[f]; ok { + return s + } + return fmt.Sprintf("Unknown flag (%d)", int(f)) + } + + type Bar struct { + flag Flag + data uintptr + } + + type Foo struct { + unexportedField Bar + ExportedField map[interface{}]interface{} + } + */ + + // Setup some sample data structures for the example. + bar := Bar{Flag(flagTwo), uintptr(0)} + s1 := Foo{bar, map[interface{}]interface{}{"one": true}} + f := Flag(5) + + // Dump! + spew.Dump(s1, f) + + // Output: + // (spew_test.Foo) { + // unexportedField: (spew_test.Bar) { + // flag: (spew_test.Flag) flagTwo, + // data: (uintptr) <nil> + // }, + // ExportedField: (map[interface {}]interface {}) { + // (string) "one": (bool) true + // } + // } + // (spew_test.Flag) Unknown flag (5) + // +} + +// This example demonstrates how to use Printf to display a variable with a +// format string and inline formatting. +func ExamplePrintf() { + // Create a double pointer to a uint 8. + ui8 := uint8(5) + pui8 := &ui8 + ppui8 := &pui8 + + // Create a circular data type. + type circular struct { + ui8 uint8 + c *circular + } + c := circular{ui8: 1} + c.c = &c + + // Print! + spew.Printf("ppui8: %v\n", ppui8) + spew.Printf("circular: %v\n", c) + + // Output: + // ppui8: <**>5 + // circular: {1 <*>{1 <*><shown>}} +} diff --git a/spew/format.go b/spew/format.go new file mode 100644 index 0000000..cc27180 --- /dev/null +++ b/spew/format.go @@ -0,0 +1,338 @@ +/* + * Copyright (c) 2013 Dave Collins <[email protected]> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +package spew + +import ( + "bytes" + "fmt" + "reflect" + "strconv" + "strings" +) + +// supportedFlags is a list of all the character flags supported by fmt package. +const supportedFlags = "0-+# " + +// formatState implements the fmt.Formatter interface and contains information +// about the state of a formatting operation. The NewFormatter function can +// be used to get a new Formatter which can be used directly as arguments +// in standard fmt package printing calls. +type formatState struct { + value interface{} + buffer bytes.Buffer + depth int + pointers map[uintptr]int // Holds map of points and depth they were seen at + fs fmt.State +} + +// buildDefaultFormat recreates the original format string without precision +// and width information to pass in to fmt.Sprintf in the case of an +// unrecognized type. Unless new types are added to the language, this +// function won't ever be called. +func (f *formatState) buildDefaultFormat() (format string) { + buf := bytes.NewBuffer(percentBytes) + + for _, flag := range supportedFlags { + if f.fs.Flag(int(flag)) { + buf.WriteRune(flag) + } + } + + buf.WriteRune('v') + + format = buf.String() + return format +} + +// constructOrigFormat recreates the original format string including precision +// and width information to pass along to the standard fmt package. This allows +// automatic deferral of all format strings this package doesn't support. +func (f *formatState) constructOrigFormat(verb rune) (format string) { + buf := bytes.NewBuffer(percentBytes) + + for _, flag := range supportedFlags { + if f.fs.Flag(int(flag)) { + buf.WriteRune(flag) + } + } + + if width, ok := f.fs.Width(); ok { + buf.WriteString(strconv.Itoa(width)) + } + + if precision, ok := f.fs.Precision(); ok { + buf.Write(precisionBytes) + buf.WriteString(strconv.Itoa(precision)) + } + + buf.WriteRune(verb) + + format = buf.String() + return format +} + +// formatPtr handles formatting of pointers by indirecting them as necessary. +func (f *formatState) formatPtr(v reflect.Value) { + // Display nil if top level poiner is nil. + if v.IsNil() { + f.buffer.Write(nilAngleBytes) + return + } + + // Remove pointers at or below the current depth from map used to detect + // circular refs. + for k, depth := range f.pointers { + if depth >= f.depth { + delete(f.pointers, k) + } + } + + plusSyntax := f.fs.Flag('+') + + // Keep list of all dereferenced pointers to possibly show later. + pointerChain := make([]uintptr, 0) + + // Figure out how many levels of indirection there are by derferencing + // pointers and unpacking interfaces down the chain while detecting circular + // references. + nilFound := false + cycleFound := false + indirects := 0 + ve := v + for ve.Kind() == reflect.Ptr { + indirects++ + if ve.IsNil() { + nilFound = true + break + } + addr := ve.Pointer() + pointerChain = append(pointerChain, addr) + if pd, ok := f.pointers[addr]; ok && pd < f.depth { + cycleFound = true + break + } + f.pointers[addr] = f.depth + + ve = ve.Elem() + if ve.Kind() == reflect.Interface { + if ve.IsNil() { + nilFound = true + break + } + ve = ve.Elem() + } + } + + // Display indirection level. + f.buffer.Write(openAngleBytes) + f.buffer.WriteString(strings.Repeat("*", indirects)) + f.buffer.Write(closeAngleBytes) + + // Display pointer information depending on flags. + if plusSyntax && (len(pointerChain) > 0) { + f.buffer.Write(openParenBytes) + for i, addr := range pointerChain { + if i > 0 { + f.buffer.Write(pointerChainBytes) + } + printHexPtr(&f.buffer, addr) + } + f.buffer.Write(closeParenBytes) + } + + // Display dereferenced value. + switch { + case nilFound == true: + f.buffer.Write(nilAngleBytes) + + case cycleFound == true: + f.buffer.Write(circularShortBytes) + + default: + f.format(ve) + } +} + +// format is the main workhorse for providing the Formatter interface. It +// uses the passed reflect value to figure out what kind of object we are +// dealing with and formats it appropriately. It is a recursive function, +// however circular data structures are detected and handled properly. +func (f *formatState) format(v reflect.Value) { + // Call error/Stringer interfaces if they exist and the handle methods + // flag is enabled. + kind := v.Kind() + if !Config.DisableMethods { + if (kind != reflect.Invalid) && (kind != reflect.Interface) { + if handled := handleMethods(&f.buffer, v); handled { + return + } + } + } + + switch kind { + case reflect.Invalid: + f.buffer.Write(invalidAngleBytes) + + case reflect.Bool: + printBool(&f.buffer, v.Bool()) + + case reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int: + printInt(&f.buffer, v.Int()) + + case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint: + printUint(&f.buffer, v.Uint()) + + case reflect.Float32: + printFloat(&f.buffer, v.Float(), 32) + + case reflect.Float64: + printFloat(&f.buffer, v.Float(), 64) + + case reflect.Complex64: + printComplex(&f.buffer, v.Complex(), 32) + + case reflect.Complex128: + printComplex(&f.buffer, v.Complex(), 64) + + case reflect.Array, reflect.Slice: + f.buffer.WriteRune('[') + f.depth++ + if (Config.MaxDepth != 0) && (f.depth > Config.MaxDepth) { + f.buffer.Write(maxShortBytes) + } else { + numEntries := v.Len() + for i := 0; i < numEntries; i++ { + if i > 0 { + f.buffer.WriteRune(' ') + } + f.format(unpackValue(v.Index(i))) + } + } + f.depth-- + f.buffer.WriteRune(']') + + case reflect.String: + f.buffer.WriteString(v.String()) + + case reflect.Interface: + // Do nothing. We should never get here due to unpackValue calls + + case reflect.Map: + f.buffer.Write(openMapBytes) + f.depth++ + if (Config.MaxDepth != 0) && (f.depth > Config.MaxDepth) { + f.buffer.Write(maxShortBytes) + } else { + keys := v.MapKeys() + for i, key := range keys { + if i > 0 { + f.buffer.WriteRune(' ') + } + f.format(unpackValue(key)) + f.buffer.WriteRune(':') + f.format(unpackValue(v.MapIndex(key))) + } + } + f.depth-- + f.buffer.Write(closeMapBytes) + + case reflect.Ptr: + f.formatPtr(v) + + case reflect.Struct: + numFields := v.NumField() + f.buffer.WriteRune('{') + f.depth++ + if (Config.MaxDepth != 0) && (f.depth > Config.MaxDepth) { + f.buffer.Write(maxShortBytes) + } else { + vt := v.Type() + for i := 0; i < numFields; i++ { + if i > 0 { + f.buffer.WriteRune(' ') + } + vtf := vt.Field(i) + if f.fs.Flag('+') { + f.buffer.WriteString(vtf.Name) + f.buffer.WriteRune(':') + } + f.format(unpackValue(v.Field(i))) + } + } + f.depth-- + f.buffer.WriteRune('}') + + case reflect.Uintptr: + printHexPtr(&f.buffer, uintptr(v.Uint())) + + case reflect.UnsafePointer, reflect.Chan, reflect.Func: + printHexPtr(&f.buffer, v.Pointer()) + + // There were not any other types at the time this code was written, but + // fall back to letting the default fmt package handle it if any get added. + default: + format := f.buildDefaultFormat() + if v.CanInterface() { + f.buffer.WriteString(fmt.Sprintf(format, v.Interface())) + } else { + f.buffer.WriteString(fmt.Sprintf(format, v.String())) + } + } +} + +// Format satisfies the fmt.Formatter interface. See NewFormatter for usage +// details. +func (f *formatState) Format(fs fmt.State, verb rune) { + f.fs = fs + + // Use standard formatting for verbs that are not v or #v. + if (verb != 'v') || (verb == 'v' && fs.Flag('#')) { + format := f.constructOrigFormat(verb) + fmt.Fprintf(fs, format, f.value) + return + } + + if f.value == nil { + fmt.Fprint(fs, string(nilAngleBytes)) + return + } + + f.format(reflect.ValueOf(f.value)) + f.buffer.WriteTo(fs) +} + +/* +NewFormatter returns a custom formatter that satisfies the fmt.Formatter +interface. As a result, it integrates cleanly with standard fmt package +printing functions. The formatter is useful for inline printing of smaller data +types similar to the standard %v format specifier. + +The custom formatter only responds to the %v and %+v verb combinations. Any +other variations such as %x, %q, and %#v will be sent to the the standard fmt +package for formatting. In addition, the custom formatter ignores the width and +precision arguments (however they will still work on the format specifiers not +handled by the custom formatter). + +Typically this function shouldn't be called directly. It is much easier to make +use of the custom formatter is to call one of the convenience functions such as +Printf, Println, or Printf. +*/ +func NewFormatter(v interface{}) (f fmt.Formatter) { + fs := &formatState{value: v} + fs.pointers = make(map[uintptr]int) + return fs +} diff --git a/spew/spew.go b/spew/spew.go new file mode 100644 index 0000000..a599978 --- /dev/null +++ b/spew/spew.go @@ -0,0 +1,115 @@ +/* + * Copyright (c) 2013 Dave Collins <[email protected]> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +package spew + +import ( + "fmt" + "io" +) + +// Errorf is a wrapper for fmt.Errorf that treats each argument as if it were +// passed with a default Formatter interface returned by NewFormatter. It +// returns the formatted string as a value that satisfies error. See +// NewFormatter for formatting details. +// +// This function is shorthand for the following syntax: +// +// fmt.Errorf(format, spew.NewFormatter(a), spew.NewFormatter(b)) +func Errorf(format string, a ...interface{}) (err error) { + return fmt.Errorf(format, convertArgs(a)...) +} + +// Fprint is a wrapper for fmt.Fprint that treats each argument as if it were +// passed with a default Formatter interface returned by NewFormatter. It +// returns the number of bytes written and any write error encountered. See +// NewFormatter for formatting details. +// +// This function is shorthand for the following syntax: +// +// fmt.Fprint(w, spew.NewFormatter(a), spew.NewFormatter(b)) +func Fprint(w io.Writer, a ...interface{}) (n int, err error) { + return fmt.Fprint(w, convertArgs(a)...) +} + +// Fprintf is a wrapper for fmt.Fprintf that treats each argument as if it were +// passed with a default Formatter interface returned by NewFormatter. It +// returns the number of bytes written and any write error encountered. See +// NewFormatter for formatting details. +// +// This function is shorthand for the following syntax: +// +// fmt.Fprintf(w, format, spew.NewFormatter(a), spew.NewFormatter(b)) +func Fprintf(w io.Writer, format string, a ...interface{}) (n int, err error) { + return fmt.Fprintf(w, format, convertArgs(a)...) +} + +// Fprintln is a wrapper for fmt.Fprintln that treats each argument as if it +// passed with a default Formatter interface returned by NewFormatter. See +// NewFormatter for formatting details. +// +// This function is shorthand for the following syntax: +// +// fmt.Fprintln(w, spew.NewFormatter(a), spew.NewFormatter(b)) +func Fprintln(w io.Writer, a ...interface{}) (n int, err error) { + return fmt.Fprintln(w, convertArgs(a)...) +} + +// Print is a wrapper for fmt.Print that treats each argument as if it were +// passed with a default Formatter interface returned by NewFormatter. It +// returns the number of bytes written and any write error encountered. See +// NewFormatter for formatting details. +// +// This function is shorthand for the following syntax: +// +// fmt.Print(spew.NewFormatter(a), spew.NewFormatter(b)) +func Print(a ...interface{}) (n int, err error) { + return fmt.Print(convertArgs(a)...) +} + +// Printf is a wrapper for fmt.Printf that treats each argument as if it were +// passed with a default Formatter interface returned by NewFormatter. It +// returns the number of bytes written and any write error encountered. See +// NewFormatter for formatting details. +// +// This function is shorthand for the following syntax: +// +// fmt.Printf(format, spew.NewFormatter(a), spew.NewFormatter(b)) +func Printf(format string, a ...interface{}) (n int, err error) { + return fmt.Printf(format, convertArgs(a)...) +} + +// Println is a wrapper for fmt.Println that treats each argument as if it were +// passed with a default Formatter interface returned by NewFormatter. It +// returns the number of bytes written and any write error encountered. See +// NewFormatter for formatting details. +// +// This function is shorthand for the following syntax: +// +// fmt.Println(spew.NewFormatter(a), spew.NewFormatter(b)) +func Println(a ...interface{}) (n int, err error) { + return fmt.Println(convertArgs(a)...) +} + +// convertArgs accepts a slice of arguments and returns a slice of the same +// length with each argument converted to a default spew Formatter interface. +func convertArgs(args []interface{}) (formatters []interface{}) { + formatters = make([]interface{}, len(args)) + for index, arg := range args { + formatters[index] = NewFormatter(arg) + } + return formatters +} |