Move Google3-specific stack limitation logic to template classes.

include/private/SkTemplates.h

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkTemplates_DEFINED
@@ skipping 146 matching lines @@
     void swap(SkAutoTArray& other) {
         SkTSwap(fArray, other.fArray);
         SkDEBUGCODE(SkTSwap(fCount, other.fCount));
     }
 
 private:
     T*  fArray;
     SkDEBUGCODE(int fCount;)
 };
 
-/** Wraps SkAutoTArray, with room for up to N elements preallocated
+/** Wraps SkAutoTArray, with room for kCountRequested elements preallocated.
  */
-template <int N, typename T> class SkAutoSTArray : SkNoncopyable {
+template <int kCountRequested, typename T> class SkAutoSTArray : SkNoncopyable {
 public:
     /** Initialize with no objects */
     SkAutoSTArray() {
         fArray = NULL;
         fCount = 0;
     }
 
     /** Allocate count number of T elements
      */
     SkAutoSTArray(int count) {
         fArray = NULL;
         fCount = 0;
         this->reset(count);
     }
 
     ~SkAutoSTArray() {
         this->reset(0);
     }
 
     /** Destroys previous objects in the array and default constructs count number of objects */
     void reset(int count) {
         T* start = fArray;
         T* iter = start + fCount;
         while (iter > start) {
             (--iter)->~T();
         }
 
         if (fCount != count) {
-            if (fCount > N) {
+            if (fCount > kCount) {
                 // 'fArray' was allocated last time so free it now
                 SkASSERT((T*) fStorage != fArray);
                 sk_free(fArray);
             }
 
-            if (count > N) {
+            if (count > kCount) {
                 const uint64_t size64 = sk_64_mul(count, sizeof(T));
                 const size_t size = static_cast<size_t>(size64);
                 if (size != size64) {
                     sk_out_of_memory();
                 }
                 fArray = (T*) sk_malloc_throw(size);
             } else if (count > 0) {
                 fArray = (T*) fStorage;
             } else {
                 fArray = NULL;
@@ skipping 18 matching lines @@
     T* get() const { return fArray; }
 
     /** Return the nth element in the array
      */
     T&  operator[](int index) const {
         SkASSERT(index < fCount);
         return fArray[index];
     }
 
 private:
+#if defined(GOOGLE3)
+    // Stack frame size is limited for GOOGLE3. 4k is less than the actual max, but some functions
+    // have multiple large stack allocations.
+    static const int kMaxBytes = 4 * 1024;
+    static const int kCount = kCountRequested * sizeof(T) > kMaxBytes
+        ? kMaxBytes / sizeof(T)
+        : kCountRequested;
+#else
+    static const int kCount = kCountRequested;
+#endif
+
     int     fCount;
     T*      fArray;
     // since we come right after fArray, fStorage should be properly aligned
-    char    fStorage[N * sizeof(T)];
+    char    fStorage[kCount * sizeof(T)];
 };
 
 /** Manages an array of T elements, freeing the array in the destructor.
  *  Does NOT call any constructors/destructors on T (T must be POD).
  */
 template <typename T> class SkAutoTMalloc : SkNoncopyable {
 public:
     /** Takes ownership of the ptr. The ptr must be a value which can be passed to sk_free. */
     explicit SkAutoTMalloc(T* ptr = NULL) {
         fPtr = ptr;
@@ skipping 53 matching lines @@
     T* detach() {
         T* ptr = fPtr;
         fPtr = NULL;
         return ptr;
     }
 
 private:
     T* fPtr;
 };
 
-template <size_t N, typename T> class SkAutoSTMalloc : SkNoncopyable {
+template <size_t kCountRequested, typename T> class SkAutoSTMalloc : SkNoncopyable {
 public:
     SkAutoSTMalloc() : fPtr(fTStorage) {}
 
     SkAutoSTMalloc(size_t count) {
-        if (count > N) {
+        if (count > kCount) {
             fPtr = (T*)sk_malloc_flags(count * sizeof(T), SK_MALLOC_THROW | SK_MALLOC_TEMP);
         } else {
             fPtr = fTStorage;
         }
     }
 
     ~SkAutoSTMalloc() {
         if (fPtr != fTStorage) {
             sk_free(fPtr);
         }
     }
 
     // doesn't preserve contents
     T* reset(size_t count) {
         if (fPtr != fTStorage) {
             sk_free(fPtr);
         }
-        if (count > N) {
+        if (count > kCount) {
             fPtr = (T*)sk_malloc_throw(count * sizeof(T));
         } else {
             fPtr = fTStorage;
         }
         return fPtr;
     }
 
     T* get() const { return fPtr; }
 
     operator T*() {
         return fPtr;
     }
 
     operator const T*() const {
         return fPtr;
     }
 
     T& operator[](int index) {
         return fPtr[index];
     }
 
     const T& operator[](int index) const {
         return fPtr[index];
     }
 
     // Reallocs the array, can be used to shrink the allocation.  Makes no attempt to be intelligent
     void realloc(size_t count) {
-        if (count > N) {
+        if (count > kCount) {
             if (fPtr == fTStorage) {
                 fPtr = (T*)sk_malloc_throw(count * sizeof(T));
-                memcpy(fPtr, fTStorage, N * sizeof(T));
+                memcpy(fPtr, fTStorage, kCount * sizeof(T));
             } else {
                 fPtr = (T*)sk_realloc_throw(fPtr, count * sizeof(T));
             }
         } else if (fPtr != fTStorage) {
             fPtr = (T*)sk_realloc_throw(fPtr, count * sizeof(T));
         }
     }
 
 private:
+    // Since we use uint32_t storage, we might be able to get more elements for free.
+    static const size_t kCountWithPadding = SkAlign4(kCountRequested*sizeof(T)) / sizeof(T);
+#if defined(GOOGLE3)
+    // Stack frame size is limited for GOOGLE3. 4k is less than the actual max, but some functions
+    // have multiple large stack allocations.
+    static const size_t kMaxBytes = 4 * 1024;
+    static const size_t kCount = kCountRequested * sizeof(T) > kMaxBytes
+        ? kMaxBytes / sizeof(T)
+        : kCountWithPadding;
+#else
+    static const size_t kCount = kCountWithPadding;
+#endif
+
     T*          fPtr;
     union {
-        uint32_t    fStorage32[(N*sizeof(T) + 3) >> 2];
+        uint32_t    fStorage32[SkAlign4(kCount*sizeof(T)) >> 2];
         T           fTStorage[1];   // do NOT want to invoke T::T()
     };
 };
 
 //////////////////////////////////////////////////////////////////////////////////////////////////
 
 /**
  *  Pass the object and the storage that was offered during SkInPlaceNewCheck, and this will
  *  safely destroy (and free if it was dynamically allocated) the object.
  */
@@ skipping 52 matching lines @@
      * Returns void* because this object does not initialize the
      * memory. Use placement new for types that require a cons.
      */
     void* get() { return fStorage.get(); }
     const void* get() const { return fStorage.get(); }
 private:
     SkAlignedSStorage<sizeof(T)*N> fStorage;
 };
 
 #endif