1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/core/SkTLS.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,84 @@
1.4 +//
1.5 +// SkTLS.h
1.6 +//
1.7 +//
1.8 +// Created by Mike Reed on 4/21/12.
1.9 +// Copyright (c) 2012 __MyCompanyName__. All rights reserved.
1.10 +//
1.11 +
1.12 +#ifndef SkTLS_DEFINED
1.13 +#define SkTLS_DEFINED
1.14 +
1.15 +#include "SkTypes.h"
1.16 +
1.17 +/**
1.18 + * Maintains a per-thread cache, using a CreateProc as the key into that cache.
1.19 + */
1.20 +class SkTLS {
1.21 +public:
1.22 + typedef void* (*CreateProc)();
1.23 + typedef void (*DeleteProc)(void*);
1.24 +
1.25 + /**
1.26 + * If Get() has previously been called with this CreateProc, then this
1.27 + * returns its cached data, otherwise it returns NULL. The CreateProc is
1.28 + * never invoked in Find, it is only used as a key for searching the
1.29 + * cache.
1.30 + */
1.31 + static void* Find(CreateProc);
1.32 +
1.33 + /**
1.34 + * Return the cached data that was returned by the CreateProc. This proc
1.35 + * is only called the first time Get is called, and there after it is
1.36 + * cached (per-thread), using the CreateProc as a key to look it up.
1.37 + *
1.38 + * When this thread, or Delete is called, the cached data is removed, and
1.39 + * if a DeleteProc was specified, it is passed the pointer to the cached
1.40 + * data.
1.41 + */
1.42 + static void* Get(CreateProc, DeleteProc);
1.43 +
1.44 + /**
1.45 + * Remove (optionally calling the DeleteProc if it was specificed in Get)
1.46 + * the cached data associated with this CreateProc. If no associated cached
1.47 + * data is found, do nothing.
1.48 + */
1.49 + static void Delete(CreateProc);
1.50 +
1.51 +private:
1.52 + // Our implementation requires only 1 TLS slot, as we manage multiple values
1.53 + // ourselves in a list, with the platform specific value as our head.
1.54 +
1.55 + /**
1.56 + * Implemented by the platform, to return the value of our (one) slot per-thread
1.57 + *
1.58 + * If forceCreateTheSlot is true, then we must have created the "slot" for
1.59 + * our TLS, even though we know that the return value will be NULL in that
1.60 + * case (i.e. no-slot and first-time-slot both return NULL). This ensures
1.61 + * that after calling GetSpecific, we know that we can legally call
1.62 + * SetSpecific.
1.63 + *
1.64 + * If forceCreateTheSlot is false, then the impl can either create the
1.65 + * slot or not.
1.66 + */
1.67 + static void* PlatformGetSpecific(bool forceCreateTheSlot);
1.68 +
1.69 + /**
1.70 + * Implemented by the platform, to set the value for our (one) slot per-thread
1.71 + *
1.72 + * The implementation can rely on GetSpecific(true) having been previously
1.73 + * called before SetSpecific is called.
1.74 + */
1.75 + static void PlatformSetSpecific(void*);
1.76 +
1.77 +public:
1.78 + /**
1.79 + * Will delete our internal list. To be called by the platform if/when its
1.80 + * TLS slot is deleted (often at thread shutdown).
1.81 + *
1.82 + * Public *only* for the platform's use, not to be called by a client.
1.83 + */
1.84 + static void Destructor(void* ptr);
1.85 +};
1.86 +
1.87 +#endif
