TrackedObjects assumes you can use a "TLS slot" of -1 to indicate uninitialized. This isn't true for the pthread_key_t type, which is unsigned on Linux and reportedly a struct on Macs. This change modifies the Slot type to be a struct containing an "initialized" flag.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@1113 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 52 insertions, 29 deletions

diff --git a/base/thread_local_storage.h b/base/thread_local_storage.h
index 245a73f..fba90ae 100644
--- a/base/thread_local_storage.h
+++ b/base/thread_local_storage.h
@@ -32,43 +32,62 @@
 
 #include "base/basictypes.h"
 
-#if defined(OS_WIN)
-typedef int TLSSlot;
-#elif defined(OS_POSIX)
+#if defined(OS_POSIX)
 #include <pthread.h>
-typedef pthread_key_t TLSSlot;
-#endif  // OS_*
+#endif
 
-// Wrapper for thread local storage.  This class doesn't
-// do much except provide an API for portability later.
+// Wrapper for thread local storage.  This class doesn't do much except provide
+// an API for portability.
 class ThreadLocalStorage {
  public:
-  // Prototype for the TLS destructor function, which can be
-  // optionally used to cleanup thread local storage on
-  // thread exit.  'value' is the data that is stored
-  // in thread local storage.
+
+  // Prototype for the TLS destructor function, which can be optionally used to
+  // cleanup thread local storage on thread exit.  'value' is the data that is
+  // stored in thread local storage.
   typedef void (*TLSDestructorFunc)(void* value);
 
-  // Allocate a TLS 'slot'.
-  // 'destructor' is a pointer to a function to perform
-  // per-thread cleanup of this object.  If set to NULL,
-  // no cleanup is done for this TLS slot.
-  // Returns an index > 0 on success, or -1 on failure.
-  static TLSSlot Alloc(TLSDestructorFunc destructor = NULL);
+  // A key representing one value stored in TLS.
+  class Slot {
+   public:
+    Slot(TLSDestructorFunc destructor = NULL);
+
+    // This constructor should be used for statics.
+    // It returns an uninitialized Slot.
+    explicit Slot(base::LinkerInitialized x) {}
+
+    // Set up the TLS slot.  Called by the constructor.
+    // 'destructor' is a pointer to a function to perform per-thread cleanup of
+    // this object.  If set to NULL, no cleanup is done for this TLS slot.
+    // Returns false on error.
+    bool Initialize(TLSDestructorFunc destructor);
+
+    // Free a previously allocated TLS 'slot'.
+    // If a destructor was set for this slot, removes
+    // the destructor so that remaining threads exiting
+    // will not free data.
+    void Free();
 
-  // Free a previously allocated TLS 'slot'.
-  // If a destructor was set for this slot, removes
-  // the destructor so that remaining threads exiting
-  // will not free data.
-  static void Free(TLSSlot slot);
+    // Get the thread-local value stored in slot 'slot'.
+    // Values are guaranteed to initially be zero.
+    void* Get() const;
 
-  // Get the thread-local value stored in slot 'slot'.
-  // Values are guaranteed to initially be zero.
-  static void* Get(TLSSlot slot);
+    // Set the thread-local value stored in slot 'slot' to
+    // value 'value'.
+    void Set(void* value);
 
-  // Set the thread-local value stored in slot 'slot' to
-  // value 'value'.
-  static void Set(TLSSlot slot, void* value);
+    bool initialized() const { return initialized_; }
+
+   private:
+    // The internals of this struct should be considered private.
+    bool initialized_;
+#if defined(OS_WIN)
+    int slot_;
+#elif defined(OS_POSIX)
+    pthread_key_t key_;
+#endif
+
+    DISALLOW_COPY_AND_ASSIGN(Slot);
+  };
 
 #if defined(OS_WIN)
   // Function called when on thread exit to call TLS
@@ -90,7 +109,11 @@ class ThreadLocalStorage {
   static TLSDestructorFunc tls_destructors_[kThreadLocalStorageSize];
 #endif  // OS_WIN
 
-  DISALLOW_EVIL_CONSTRUCTORS(ThreadLocalStorage);
+  DISALLOW_COPY_AND_ASSIGN(ThreadLocalStorage);
 };
 
+// Temporary backwards-compatible name.
+// TODO(evanm): replace all usage of TLSSlot.
+typedef ThreadLocalStorage::Slot TLSSlot;
+
 #endif  // BASE_THREAD_LOCAL_STORAGE_H_