Revert 194649 "Remove scoped_array from Chromium."

trunk/src/base/memory/scoped_ptr.h

Index: trunk/src/base/memory/scoped_ptr.h
===================================================================
--- trunk/src/base/memory/scoped_ptr.h	(revision 194652)
+++ trunk/src/base/memory/scoped_ptr.h	(working copy)
@@ -7,7 +7,7 @@
 // end of a scope.  There are two main classes you will use, which correspond
 // to the operators new/delete and new[]/delete[].
 //
-// Example usage (scoped_ptr<T>):
+// Example usage (scoped_ptr):
 //   {
 //     scoped_ptr<Foo> foo(new Foo("wee"));
 //   }  // foo goes out of scope, releasing the pointer with it.
@@ -26,9 +26,9 @@
 //                                   // manages a pointer.
 //   }  // foo wasn't managing a pointer, so nothing was destroyed.
 //
-// Example usage (scoped_ptr<T[]>):
+// Example usage (scoped_array):
 //   {
-//     scoped_ptr<Foo[]> foo(new Foo[100]);
+//     scoped_array<Foo> foo(new Foo[100]);
 //     foo.get()->Method();  // Foo::Method on the 0th element.
 //     foo[10].Method();     // Foo::Method on the 10th element.
 //   }
@@ -81,14 +81,15 @@
 //     return result.PassAs<Foo>();
 //   }
 //
-// Note that PassAs<>() is implemented only for scoped_ptr<T>, but not for
-// scoped_ptr<T[]>. This is because casting array pointers may not be safe.
+// Note that PassAs<>() is implemented only for scoped_ptr, but not for
+// scoped_array. This is because casting array pointers may not be safe.
 
 #ifndef BASE_MEMORY_SCOPED_PTR_H_
 #define BASE_MEMORY_SCOPED_PTR_H_
 
 // This is an implementation designed to match the anticipated future TR2
-// implementation of the scoped_ptr class and scoped_ptr_malloc (deprecated).
+// implementation of the scoped_ptr class, and its closely-related brethren,
+// scoped_array, scoped_ptr_malloc.
 
 #include <assert.h>
 #include <stddef.h>
@@ -562,6 +563,141 @@
   return p1 != p2.get();
 }
 
+// DEPRECATED: Use scoped_ptr<C[]> instead.
+//
+// scoped_array<C> is like scoped_ptr<C>, except that the caller must allocate
+// with new [] and the destructor deletes objects with delete [].
+//
+// As with scoped_ptr<C>, a scoped_array<C> either points to an object
+// or is NULL.  A scoped_array<C> owns the object that it points to.
+// scoped_array<T> is thread-compatible, and once you index into it,
+// the returned objects have only the thread safety guarantees of T.
+//
+// Size: sizeof(scoped_array<C>) == sizeof(C*)
+template <class C>
+class scoped_array {
+  MOVE_ONLY_TYPE_FOR_CPP_03(scoped_array, RValue)
+
+ public:
+
+  // The element type
+  typedef C element_type;
+
+  // Constructor.  Defaults to initializing with NULL.
+  // There is no way to create an uninitialized scoped_array.
+  // The input parameter must be allocated with new [].
+  explicit scoped_array(C* p = NULL) : array_(p) { }
+
+  // Constructor.  Move constructor for C++03 move emulation of this type.
+  scoped_array(RValue rvalue)
+      : array_(rvalue.object->release()) {
+  }
+
+  // Destructor.  If there is a C object, delete it.
+  // We don't need to test ptr_ == NULL because C++ does that for us.
+  ~scoped_array() {
+    enum { type_must_be_complete = sizeof(C) };
+    delete[] array_;
+  }
+
+  // operator=.  Move operator= for C++03 move emulation of this type.
+  scoped_array& operator=(RValue rhs) {
+    reset(rhs.object->release());
+    return *this;
+  }
+
+  // Reset. Deletes the current owned object, if any.
+  void reset(C* p = NULL) {
+    // This is a self-reset, which is no longer allowed: http://crbug.com/162971
+    if (p != NULL && p == array_)
+      abort();
+
+    C* old = array_;
+    array_ = NULL;
+    if (old != NULL)
+      delete[] old;
+    array_ = p;
+  }
+
+  // Get one element of the current object.
+  // Will assert() if there is no current object, or index i is negative.
+  C& operator[](ptrdiff_t i) const {
+    assert(i >= 0);
+    assert(array_ != NULL);
+    return array_[i];
+  }
+
+  // Get a pointer to the zeroth element of the current object.
+  // If there is no current object, return NULL.
+  C* get() const {
+    return array_;
+  }
+
+  // Allow scoped_array<C> to be used in boolean expressions, but not
+  // implicitly convertible to a real bool (which is dangerous).
+  typedef C* scoped_array::*Testable;
+  operator Testable() const { return array_ ? &scoped_array::array_ : NULL; }
+
+  // Comparison operators.
+  // These return whether two scoped_array refer to the same object, not just to
+  // two different but equal objects.
+  bool operator==(C* p) const { return array_ == p; }
+  bool operator!=(C* p) const { return array_ != p; }
+
+  // Swap two scoped arrays.
+  void swap(scoped_array& p2) {
+    C* tmp = array_;
+    array_ = p2.array_;
+    p2.array_ = tmp;
+  }
+
+  // Release an array.
+  // The return value is the current pointer held by this object.
+  // If this object holds a NULL pointer, the return value is NULL.
+  // After this operation, this object will hold a NULL pointer,
+  // and will not own the object any more.
+  C* release() WARN_UNUSED_RESULT {
+    C* retVal = array_;
+    array_ = NULL;
+    return retVal;
+  }
+
+ private:
+  C* array_;
+
+  // Disable initialization from any type other than C*, by providing a
+  // constructor that matches such an initialization, but is private and has no
+  // definition. This is disabled because it is not safe to call delete[] on an
+  // array whose static type does not match its dynamic type.
+  template <typename C2> explicit scoped_array(C2* array);
+  explicit scoped_array(int disallow_construction_from_null);
+
+  // Disable reset() from any type other than C*, for the same reasons as the
+  // constructor above.
+  template <typename C2> void reset(C2* array);
+  void reset(int disallow_reset_from_null);
+
+  // Forbid comparison of different scoped_array types.
+  template <class C2> bool operator==(scoped_array<C2> const& p2) const;
+  template <class C2> bool operator!=(scoped_array<C2> const& p2) const;
+};
+
+// Free functions
+template <class C>
+void swap(scoped_array<C>& p1, scoped_array<C>& p2) {
+  p1.swap(p2);
+}
+
+template <class C>
+bool operator==(C* p1, const scoped_array<C>& p2) {
+  return p1 == p2.get();
+}
+
+template <class C>
+bool operator!=(C* p1, const scoped_array<C>& p2) {
+  return p1 != p2.get();
+}
+
 // DEPRECATED: Use scoped_ptr<C, base::FreeDeleter> instead.
 //
 // scoped_ptr_malloc<> is similar to scoped_ptr<>, but it accepts a