diff options
author | Ben Murdoch <benm@google.com> | 2010-07-29 17:14:53 +0100 |
---|---|---|
committer | Ben Murdoch <benm@google.com> | 2010-08-04 14:29:45 +0100 |
commit | c407dc5cd9bdc5668497f21b26b09d988ab439de (patch) | |
tree | 7eaf8707c0309516bdb042ad976feedaf72b0bb1 /base/lazy_instance.cc | |
parent | 0998b1cdac5733f299c12d88bc31ef9c8035b8fa (diff) | |
download | external_chromium-c407dc5cd9bdc5668497f21b26b09d988ab439de.zip external_chromium-c407dc5cd9bdc5668497f21b26b09d988ab439de.tar.gz external_chromium-c407dc5cd9bdc5668497f21b26b09d988ab439de.tar.bz2 |
Merge Chromium src@r53293
Change-Id: Ia79acf8670f385cee48c45b0a75371d8e950af34
Diffstat (limited to 'base/lazy_instance.cc')
-rw-r--r-- | base/lazy_instance.cc | 45 |
1 files changed, 24 insertions, 21 deletions
diff --git a/base/lazy_instance.cc b/base/lazy_instance.cc index 9923253..f98ba3f 100644 --- a/base/lazy_instance.cc +++ b/base/lazy_instance.cc @@ -6,41 +6,44 @@ #include "base/at_exit.h" #include "base/atomicops.h" -#include "base/dynamic_annotations.h" #include "base/basictypes.h" #include "base/platform_thread.h" +#include "base/third_party/dynamic_annotations/dynamic_annotations.h" namespace base { -void LazyInstanceHelper::EnsureInstance(void* instance, - void (*ctor)(void*), - void (*dtor)(void*)) { +bool LazyInstanceHelper::NeedsInstance() { // Try to create the instance, if we're the first, will go from EMPTY // to CREATING, otherwise we've already been beaten here. if (base::subtle::Acquire_CompareAndSwap( &state_, STATE_EMPTY, STATE_CREATING) == STATE_EMPTY) { - // Created the instance in the space provided by |instance|. - ctor(instance); - - // See the comment to the corresponding HAPPENS_AFTER in Pointer(). - ANNOTATE_HAPPENS_BEFORE(&state_); - - // Instance is created, go from CREATING to CREATED. - base::subtle::Release_Store(&state_, STATE_CREATED); - - // Allow reusing the LazyInstance (reset it to the initial state). This - // makes possible calling all AtExit callbacks between tests. Assumes that - // no other threads execute when AtExit callbacks are processed. - base::AtExitManager::RegisterCallback(&LazyInstanceHelper::ResetState, - this); - - // Make sure that the lazily instantiated object will get destroyed at exit. - base::AtExitManager::RegisterCallback(dtor, instance); + // Caller must create instance + return true; } else { // It's either in the process of being created, or already created. Spin. while (base::subtle::NoBarrier_Load(&state_) != STATE_CREATED) PlatformThread::YieldCurrentThread(); } + + // Someone else created the instance. + return false; +} + +void LazyInstanceHelper::CompleteInstance(void* instance, void (*dtor)(void*)) { + // See the comment to the corresponding HAPPENS_AFTER in Pointer(). + ANNOTATE_HAPPENS_BEFORE(&state_); + + // Instance is created, go from CREATING to CREATED. + base::subtle::Release_Store(&state_, STATE_CREATED); + + // Allow reusing the LazyInstance (reset it to the initial state). This + // makes possible calling all AtExit callbacks between tests. Assumes that + // no other threads execute when AtExit callbacks are processed. + base::AtExitManager::RegisterCallback(&LazyInstanceHelper::ResetState, + this); + + // Make sure that the lazily instantiated object will get destroyed at exit. + base::AtExitManager::RegisterCallback(dtor, instance); } // static |