Attempt to reland 8264-5 with warning-as-error fixes.

git-svn-id: http://skia.googlecode.com/svn/trunk@8272 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 21 insertions, 1 deletions

diff --git a/include/core/SkTLazy.h b/include/core/SkTLazy.h
index b9052f0d99..1934b5dff9 100644
--- a/include/core/SkTLazy.h
+++ b/include/core/SkTLazy.h
@@ -14,6 +14,9 @@
 #include "SkTypes.h"
 #include <new>
 
+template <typename T> class SkTLazy;
+template <typename T> void* operator new(size_t, SkTLazy<T>* lazy);
+
 /**
  *  Efficient way to defer allocating/initializing a class until it is needed
  *  (if ever).
@@ -44,7 +47,7 @@ public:
 
     /**
      *  Return a pointer to a default-initialized instance of the class. If a
-     *  previous instance had been initialzied (either from init() or set()) it
+     *  previous instance had been initialized (either from init() or set()) it
      *  will first be destroyed, so that a freshly initialized instance is
      *  always returned.
      */
@@ -84,10 +87,27 @@ public:
     T* get() const { SkASSERT(this->isValid()); return fPtr; }
 
 private:
+    friend void* operator new<T>(size_t, SkTLazy* lazy);
+
     T*   fPtr; // NULL or fStorage
     char fStorage[sizeof(T)];
 };
 
+// Use the below macro (SkNEW_IN_TLAZY) rather than calling this directly
+template <typename T> void* operator new(size_t, SkTLazy<T>* lazy) {
+    SkASSERT(!lazy->isValid());
+    lazy->fPtr = reinterpret_cast<T*>(lazy->fStorage);
+    return lazy->fPtr;
+}
+
+// Skia doesn't use C++ exceptions but it may be compiled with them enabled. Having an op delete
+// to match the op new silences warnings about missing op delete when a constructor throws an
+// exception.
+template <typename T> void operator delete(void*, SkTLazy<T>) { SK_CRASH(); }
+
+// Use this to construct a T inside an SkTLazy using a non-default constructor.
+#define SkNEW_IN_TLAZY(tlazy_ptr, type_name, args) (new (tlazy_ptr) type_name args)
+
 /**
  * A helper built on top of SkTLazy to do copy-on-first-write. The object is initialized
  * with a const pointer but provides a non-const pointer accessor. The first time the