1 files changed, 126 insertions, 0 deletions
diff --git a/comctl_windows.go b/comctl_windows.go
new file mode 100644
index 0000000..56a7bfb
--- /dev/null
+++ b/comctl_windows.go
@@ -0,0 +1,126 @@
+// 25 february 2014
+
+package ui
+
+import (
+	"fmt"
+	"io/ioutil"
+	"syscall"
+	"unsafe"
+)
+
+// pretty much every constant here except _WM_USER is from commctrl.h, except where noted
+
+var (
+	comctlManifestCookie uintptr
+)
+
+var (
+	_activateActCtx = kernel32.NewProc("ActivateActCtx")
+	_createActCtx   = kernel32.NewProc("CreateActCtxW")
+)
+
+/*
+Windows requires a manifest file to enable Common Controls version 6.
+The only way to not require an external manifest is to synthesize the manifest ourselves.
+We can use the activation context API to load it at runtime.
+References:
+- http://stackoverflow.com/questions/4308503/how-to-enable-visual-styles-without-a-manifest
+- http://support.microsoft.com/kb/830033
+*/
+func forceCommonControls6() (err error) {
+	manifestfile, err := ioutil.TempFile("", "gouicomctl32v6manifest")
+	if err != nil {
+		return fmt.Errorf("error creating synthesized manifest file: %v", err)
+	}
+	_, err = manifestfile.Write(manifest)
+	if err != nil {
+		return fmt.Errorf("error writing synthesized manifest file: %v", err)
+	}
+	filename := manifestfile.Name()
+	// we now have to close the file, otherwise ActivateActCtx() will complain that it's in use by another program
+	// if ioutil.TempFile() ever changes so that the file is deleted when it is closed, this will need to change
+	manifestfile.Close()
+
+	var actctx struct {
+		cbSize                 uint32
+		dwFlags                uint32
+		lpSource               *uint16
+		wProcessorArchitecture uint16
+		wLangId                uint16  // originally LANGID
+		lpAssemblyDirectory    uintptr // originally LPCWSTR
+		lpResourceName         uintptr // originally LPCWSTR
+		lpApplicationName      uintptr // originally LPCWSTR
+		hModule                _HANDLE // originally HMODULE
+	}
+
+	actctx.cbSize = uint32(unsafe.Sizeof(actctx))
+	// make this context the process default, just to be safe
+	actctx.dwFlags = _ACTCTX_FLAG_SET_PROCESS_DEFAULT
+	actctx.lpSource = toUTF16(filename)
+
+	r1, _, err := _createActCtx.Call(uintptr(unsafe.Pointer(&actctx)))
+	// don't negConst() INVALID_HANDLE_VALUE; windowsconstgen was given a pointer by windows.h, and pointers are unsigned, so converting it back to signed doesn't work
+	if r1 == _INVALID_HANDLE_VALUE { // failure
+		return fmt.Errorf("error creating activation context for synthesized manifest file: %v", err)
+	}
+	r1, _, err = _activateActCtx.Call(
+		r1,
+		uintptr(unsafe.Pointer(&comctlManifestCookie)))
+	if r1 == uintptr(_FALSE) { // failure
+		return fmt.Errorf("error activating activation context for synthesized manifest file: %v", err)
+	}
+	return nil
+}
+
+func initCommonControls() (err error) {
+	var icc struct {
+		dwSize uint32
+		dwICC  uint32
+	}
+
+	err = forceCommonControls6()
+	if err != nil {
+		return fmt.Errorf("error forcing Common Controls version 6 (or newer): %v", err)
+	}
+
+	icc.dwSize = uint32(unsafe.Sizeof(icc))
+	icc.dwICC = _ICC_PROGRESS_CLASS
+
+	comctl32 = syscall.NewLazyDLL("comctl32.dll")
+	r1, _, err := comctl32.NewProc("InitCommonControlsEx").Call(uintptr(unsafe.Pointer(&icc)))
+	if r1 == _FALSE { // failure
+		return fmt.Errorf("error initializing Common Controls (comctl32.dll); Windows last error: %v", err)
+	}
+	return nil
+}
+
+// Common Controls class names.
+const (
+	// x (lowercase) prefix to avoid being caught by the constants generator
+	x_PROGRESS_CLASS = "msctls_progress32"
+)
+
+var manifest = []byte(`<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
+<assemblyIdentity
+    version="1.0.0.0"
+    processorArchitecture="*"
+    name="CompanyName.ProductName.YourApplication"
+    type="win32"
+/>
+<description>Your application description here.</description>
+<dependency>
+    <dependentAssembly>
+        <assemblyIdentity
+            type="win32"
+            name="Microsoft.Windows.Common-Controls"
+            version="6.0.0.0"
+            processorArchitecture="*"
+            publicKeyToken="6595b64144ccf1df"
+            language="*"
+        />
+    </dependentAssembly>
+</dependency>
+</assembly>
+`)