diff options
| -rw-r--r-- | cache.go | 58 | ||||
| -rw-r--r-- | init.go | 4 | ||||
| -rw-r--r-- | structs.go | 6 |
3 files changed, 68 insertions, 0 deletions
diff --git a/cache.go b/cache.go new file mode 100644 index 0000000..c139306 --- /dev/null +++ b/cache.go @@ -0,0 +1,58 @@ +// I put this here to look at and think about +// from mod/sumdb/cache.go + +// Parallel cache. +// This file is copied from cmd/go/internal/par. + +package forgepb + +import ( + "sync" + "sync/atomic" +) + +// parCache runs an action once per key and caches the result. +type parCache struct { + m sync.Map +} + +type cacheEntry struct { + done uint32 + mu sync.Mutex + result interface{} +} + +// Do calls the function f if and only if Do is being called for the first time with this key. +// No call to Do with a given key returns until the one call to f returns. +// Do returns the value returned by the one call to f. +func (c *parCache) Do(key interface{}, f func() interface{}) interface{} { + entryIface, ok := c.m.Load(key) + if !ok { + entryIface, _ = c.m.LoadOrStore(key, new(cacheEntry)) + } + e := entryIface.(*cacheEntry) + if atomic.LoadUint32(&e.done) == 0 { + e.mu.Lock() + if atomic.LoadUint32(&e.done) == 0 { + e.result = f() + atomic.StoreUint32(&e.done, 1) + } + e.mu.Unlock() + } + return e.result +} + +// Get returns the cached result associated with key. +// It returns nil if there is no such result. +// If the result for key is being computed, Get does not wait for the computation to finish. +func (c *parCache) Get(key interface{}) interface{} { + entryIface, ok := c.m.Load(key) + if !ok { + return nil + } + e := entryIface.(*cacheEntry) + if atomic.LoadUint32(&e.done) == 0 { + return nil + } + return e.result +} @@ -24,6 +24,10 @@ func init() { func Init() *Forge { f := new(Forge) + + // cache.go has Do() + // f.initOnce.Do(f.initWork) + f.Config = new(ForgeConfigs) // load the ~/.config/forge/ config @@ -1,12 +1,18 @@ package forgepb import ( + sync "sync" + "go.wit.com/lib/protobuf/gitpb" "go.wit.com/lib/protobuf/zoopb" ) // maybe an interface someday? type Forge struct { + // one-time initialized data + initOnce sync.Once + initErr error // init error, if any + goSrc string // the path to go/src Config *ForgeConfigs // config repos for readonly, private, etc Repos *gitpb.Repos |