Make leak counters thread-safe

include/core/SkInstCnt.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkInstCnt_DEFINED
 #define SkInstCnt_DEFINED
 
 /*
  * The instance counting system consists of three macros that create the
  * instance counting machinery. A class is added to the system by adding:
  *   SK_DECLARE_INST_COUNT at the top of its declaration for derived classes
  *   SK_DECLARE_INST_COUNT_ROOT at the top of its declaration for a root class
  * At the end of an application a call to all the "root" objects'
  * CheckInstanceCount methods should be made
  */
 #include "SkTypes.h"
 
 #if SK_ENABLE_INST_COUNT
+// Static variables inside member functions below may be defined multiple times
+// if Skia is being used as a dynamic library. Instance counting should be on
+// only for static builds. See bug skia:2058.
+#if defined(SKIA_DLL)
+#error Instance counting works only when Skia is built as a static library.
+#endif
+
+#include "SkOnce.h"
 #include "SkTArray.h"
 #include "SkThread.h"
-
 extern bool gPrintInstCount;
 
 // The non-root classes just register themselves with their parent
 #define SK_DECLARE_INST_COUNT(className)                                    \
     SK_DECLARE_INST_COUNT_INTERNAL(className,                               \
                                    INHERITED::AddInstChild(CheckInstanceCount);)
 
 // The root classes registers a function to print out the memory stats when
 // the app ends
 #define SK_DECLARE_INST_COUNT_ROOT(className)                               \
     SK_DECLARE_INST_COUNT_INTERNAL(className, atexit(exitPrint);)
 
 #define SK_DECLARE_INST_COUNT_INTERNAL(className, initStep)                 \
     class SkInstanceCountHelper {                                           \
     public:                                                                 \
-        typedef int (*PFCheckInstCnt)(int level, bool cleanUp);             \
         SkInstanceCountHelper() {                                           \
-            static bool gInited;                                            \
-            if (!gInited) {                                                 \
-                initStep                                                    \
-                GetChildren() = new SkTArray<PFCheckInstCnt>;               \
-                gInited = true;                                             \
-            }                                                               \
+            SK_DECLARE_STATIC_ONCE(once);                                   \
+            SkOnce(&once, init, 0);                                         \
             sk_atomic_inc(GetInstanceCountPtr());                           \
         }                                                                   \
                                                                             \
+        static void init(int) {                                             \
+            initStep                                                        \
+        }                                                                   \
+                                                                            \
         SkInstanceCountHelper(const SkInstanceCountHelper&) {               \
             sk_atomic_inc(GetInstanceCountPtr());                           \
         }                                                                   \
                                                                             \
         ~SkInstanceCountHelper() {                                          \
             sk_atomic_dec(GetInstanceCountPtr());                           \
         }                                                                   \
                                                                             \
         static int32_t* GetInstanceCountPtr() {                             \
             static int32_t gInstanceCount;                                  \
             return &gInstanceCount;                                         \
         }                                                                   \
                                                                             \
-        static SkTArray<PFCheckInstCnt>*& GetChildren() {                   \
-            static SkTArray<PFCheckInstCnt>* gChildren;                     \
+        static SkTArray<int (*)(int, bool)>*& GetChildren() {               \
+            static SkTArray<int (*)(int, bool)>* gChildren;                 \
             return gChildren;                                               \
         }                                                                   \
                                                                             \
+        static SkBaseMutex& GetChildrenMutex() {                            \
+            SK_DECLARE_STATIC_MUTEX(childrenMutex);                         \
+            return childrenMutex;                                           \
+        }                                                                   \
+                                                                            \
     } fInstanceCountHelper;                                                 \
                                                                             \
     static int32_t GetInstanceCount() {                                     \
         return *SkInstanceCountHelper::GetInstanceCountPtr();               \
     }                                                                       \
                                                                             \
     static void exitPrint() {                                               \
         CheckInstanceCount(0, true);                                        \
     }                                                                       \
                                                                             \
     static int CheckInstanceCount(int level = 0, bool cleanUp = false) {    \
         if (gPrintInstCount && 0 != GetInstanceCount()) {                   \
             SkDebugf("%*c Leaked %s: %d\n",                                 \
                      4*level, ' ', #className,                              \
                      GetInstanceCount());                                   \
         }                                                                   \
         if (NULL == SkInstanceCountHelper::GetChildren()) {                 \
             return GetInstanceCount();                                      \
         }                                                                   \
-        SkTArray<int (*)(int, bool)>* children =                            \
+        SkTArray<int (*)(int, bool)>* children = \
             SkInstanceCountHelper::GetChildren();                           \
         int childCount = children->count();                                 \
         int count = GetInstanceCount();                                     \
         for (int i = 0; i < childCount; ++i) {                              \
             count -= (*(*children)[i])(level+1, cleanUp);                   \
         }                                                                   \
         SkASSERT(count >= 0);                                               \
         if (gPrintInstCount && childCount > 0 && count > 0) {               \
             SkDebugf("%*c Leaked ???: %d\n", 4*(level + 1), ' ', count);    \
         }                                                                   \
         if (cleanUp) {                                                      \
             delete children;                                                \
             SkInstanceCountHelper::GetChildren() = NULL;                    \
         }                                                                   \
         return GetInstanceCount();                                          \
     }                                                                       \
                                                                             \
     static void AddInstChild(int (*childCheckInstCnt)(int, bool)) {         \
-        if (CheckInstanceCount != childCheckInstCnt &&                      \
-            NULL != SkInstanceCountHelper::GetChildren()) {                 \
+        if (CheckInstanceCount != childCheckInstCnt) {                      \
+            SkAutoMutexAcquire ama(SkInstanceCountHelper::GetChildrenMutex()); \
+            if (NULL == SkInstanceCountHelper::GetChildren()) {             \
+                SkInstanceCountHelper::GetChildren() =                      \
+                    new SkTArray<int (*)(int, bool)>;                       \
+            }                                                               \
             SkInstanceCountHelper::GetChildren()->push_back(childCheckInstCnt); \
         }                                                                   \
     }
 
 #else
 // Typically SK_ENABLE_INST_COUNT=0. Make sure the class declares public typedef INHERITED by
 // causing a compile-time error if the typedef is missing. This way SK_ENABLE_INST_COUNT=1 stays
 // compiling.
 #define SK_DECLARE_INST_COUNT(className) static void AddInstChild() { INHERITED::AddInstChild(); }
 #define SK_DECLARE_INST_COUNT_ROOT(className) static void AddInstChild() { }
 #endif
 
 // Following are deprecated. They are defined only for backwards API compatibility.
 #define SK_DECLARE_INST_COUNT_TEMPLATE(className) SK_DECLARE_INST_COUNT(className)
 #define SK_DEFINE_INST_COUNT(className)
 #define SK_DEFINE_INST_COUNT_TEMPLATE(templateInfo, className)
 
 #endif // SkInstCnt_DEFINED