diff options
Diffstat (limited to 'librsync/pointers.go')
-rw-r--r-- | librsync/pointers.go | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/librsync/pointers.go b/librsync/pointers.go new file mode 100644 index 0000000..d14f41f --- /dev/null +++ b/librsync/pointers.go @@ -0,0 +1,51 @@ +package librsync + +import ( + "sync" +) + +// pointerMap holds Go *Patcher objects to pass to C. +// Don't touch this data structure, instead use the storePatcher, getPatcher, +// and dropPatcher functions. +var patcherStore = struct { + lock sync.Mutex + store map[uintptr]*Patcher +}{ + store: make(map[uintptr]*Patcher), +} + +// storePatcher stores the value and returns a reference to it, for use in a CGo +// call. Use the same reference for dropPatcher. C callbacks can use getPatcher +// to get the original value. +func storePatcher(patcher *Patcher, id uintptr) { + patcherStore.lock.Lock() + defer patcherStore.lock.Unlock() + + if _, ok := patcherStore.store[id]; ok { + // Just to be on the safe side. + panic("pointer already stored") + } + patcherStore.store[id] = patcher +} + +// getPatcher returns the value for the reference id. It returns nil if there +// is no such reference. +func getPatcher(id uintptr) *Patcher { + patcherStore.lock.Lock() + defer patcherStore.lock.Unlock() + + return patcherStore.store[id] +} + +// dropPatcher unreferences the value so the garbage collector can free it's +// memory. +func dropPatcher(id uintptr) { + patcherStore.lock.Lock() + defer patcherStore.lock.Unlock() + + if _, ok := patcherStore.store[id]; !ok { + panic("pointer not stored") + } + + delete(patcherStore.store, id) +} |