Update base/scoped_ptr.h from system_wrappers/interface/scoped_ptr.h
The latter file was more up-to-date. The files are now identical
with the following exceptions:
* The namespace used (rtc vs. webrtc).
* The name of the include guard.
* base/scoped_ptr.h still has two extra methods, accept() and use().
* base/scoped_ptr.h still includes webrtc/base/common.h even though
it doesn't need it itself, since several .cc files expect to get
it for free by incuding base/scoped_ptr.h. This is of course bad
manners, and the "unused" include will be removed in a future CL.
A later CL will remove system_wrappers/interface/scoped_ptr.h.
R=andrew@webrtc.org
Committed: https://code.google.com/p/webrtc/source/detail?r=8147
And reverted again, because out-of-tree code using this file was defining nullptr to 0: https://code.google.com/p/webrtc/source/detail?r=8149
Review URL: https://webrtc-codereview.appspot.com/36919004
Cr-Commit-Position: refs/heads/master@{#8196}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8196 4adac7df-926f-26a2-2b94-8c16560cd09d
This commit is contained in:
kwiberg@webrtc.org
parent
43c883954f
commit
73ca1945ec
@ -8,10 +8,12 @@
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* be found in the AUTHORS file in the root of the source tree.
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*/
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// Scopers help you manage ownership of a pointer, helping you easily manage the
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// a pointer within a scope, and automatically destroying the pointer at the
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// end of a scope. There are two main classes you will use, which correspond
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// to the operators new/delete and new[]/delete[].
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// Borrowed from Chromium's src/base/memory/scoped_ptr.h.
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// Scopers help you manage ownership of a pointer, helping you easily manage a
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// pointer within a scope, and automatically destroying the pointer at the end
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// of a scope. There are two main classes you will use, which correspond to the
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// operators new/delete and new[]/delete[].
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//
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// Example usage (scoped_ptr<T>):
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// {
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@ -64,7 +66,7 @@
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// TakesOwnership(ptr.Pass()); // ptr no longer owns Foo("yay").
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// scoped_ptr<Foo> ptr2 = CreateFoo(); // ptr2 owns the return Foo.
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// scoped_ptr<Foo> ptr3 = // ptr3 now owns what was in ptr2.
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// PassThru(ptr2.Pass()); // ptr2 is correspondingly NULL.
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// PassThru(ptr2.Pass()); // ptr2 is correspondingly nullptr.
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// }
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//
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// Notice that if you do not call Pass() when returning from PassThru(), or
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@ -93,18 +95,20 @@
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#ifndef WEBRTC_BASE_SCOPED_PTR_H__
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#define WEBRTC_BASE_SCOPED_PTR_H__
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#include <stddef.h> // for ptrdiff_t
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#include <stdlib.h> // for free() decl
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// This is an implementation designed to match the anticipated future TR2
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// implementation of the scoped_ptr class.
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#include <assert.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <algorithm> // For std::swap().
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#include "webrtc/base/common.h" // for ASSERT
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#include "webrtc/base/move.h" // for RTC_MOVE_ONLY_TYPE_FOR_CPP_03
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#include "webrtc/base/template_util.h" // for is_convertible, is_array
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#ifdef WEBRTC_WIN
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namespace std { using ::ptrdiff_t; };
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#endif // WEBRTC_WIN
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#include "webrtc/base/common.h"
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#include "webrtc/base/constructormagic.h"
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#include "webrtc/base/move.h"
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#include "webrtc/base/template_util.h"
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#include "webrtc/typedefs.h"
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namespace rtc {
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@ -176,6 +180,18 @@ struct FreeDeleter {
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namespace internal {
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template <typename T>
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struct ShouldAbortOnSelfReset {
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template <typename U>
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static rtc::internal::NoType Test(const typename U::AllowSelfReset*);
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template <typename U>
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static rtc::internal::YesType Test(...);
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static const bool value =
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sizeof(Test<T>(0)) == sizeof(rtc::internal::YesType);
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};
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// Minimal implementation of the core logic of scoped_ptr, suitable for
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// reuse in both scoped_ptr and its specializations.
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template <class T, class D>
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@ -192,8 +208,7 @@ class scoped_ptr_impl {
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scoped_ptr_impl(scoped_ptr_impl<U, V>* other)
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: data_(other->release(), other->get_deleter()) {
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// We do not support move-only deleters. We could modify our move
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// emulation to have rtc::subtle::move() and
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// rtc::subtle::forward()
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// emulation to have rtc::subtle::move() and rtc::subtle::forward()
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// functions that are imperfect emulations of their C++11 equivalents,
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// but until there's a requirement, just assume deleters are copyable.
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}
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@ -207,7 +222,7 @@ class scoped_ptr_impl {
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}
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~scoped_ptr_impl() {
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if (data_.ptr != NULL) {
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if (data_.ptr != nullptr) {
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// Not using get_deleter() saves one function call in non-optimized
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// builds.
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static_cast<D&>(data_)(data_.ptr);
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@ -215,12 +230,12 @@ class scoped_ptr_impl {
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}
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void reset(T* p) {
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// This is a self-reset, which is no longer allowed: http://crbug.com/162971
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if (p != NULL && p == data_.ptr)
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abort();
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// This is a self-reset, which is no longer allowed for default deleters:
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// https://crbug.com/162971
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assert(!ShouldAbortOnSelfReset<D>::value || p == nullptr || p != data_.ptr);
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// Note that running data_.ptr = p can lead to undefined behavior if
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// get_deleter()(get()) deletes this. In order to pevent this, reset()
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// get_deleter()(get()) deletes this. In order to prevent this, reset()
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// should update the stored pointer before deleting its old value.
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//
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// However, changing reset() to use that behavior may cause current code to
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@ -229,13 +244,13 @@ class scoped_ptr_impl {
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// then it will incorrectly dispatch calls to |p| rather than the original
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// value of |data_.ptr|.
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//
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// During the transition period, set the stored pointer to NULL while
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// During the transition period, set the stored pointer to nullptr while
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// deleting the object. Eventually, this safety check will be removed to
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// prevent the scenario initially described from occuring and
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// prevent the scenario initially described from occurring and
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// http://crbug.com/176091 can be closed.
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T* old = data_.ptr;
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data_.ptr = NULL;
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if (old != NULL)
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data_.ptr = nullptr;
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if (old != nullptr)
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static_cast<D&>(data_)(old);
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data_.ptr = p;
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}
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@ -256,12 +271,12 @@ class scoped_ptr_impl {
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T* release() {
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T* old_ptr = data_.ptr;
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data_.ptr = NULL;
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data_.ptr = nullptr;
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return old_ptr;
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}
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T** accept() {
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reset(NULL);
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reset(nullptr);
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return &(data_.ptr);
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}
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@ -293,8 +308,8 @@ class scoped_ptr_impl {
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// A scoped_ptr<T> is like a T*, except that the destructor of scoped_ptr<T>
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// automatically deletes the pointer it holds (if any).
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// That is, scoped_ptr<T> owns the T object that it points to.
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// Like a T*, a scoped_ptr<T> may hold either NULL or a pointer to a T object.
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// Also like T*, scoped_ptr<T> is thread-compatible, and once you
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// Like a T*, a scoped_ptr<T> may hold either nullptr or a pointer to a T
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// object. Also like T*, scoped_ptr<T> is thread-compatible, and once you
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// dereference it, you get the thread safety guarantees of T.
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//
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// The size of scoped_ptr is small. On most compilers, when using the
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@ -304,19 +319,24 @@ class scoped_ptr_impl {
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//
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// Current implementation targets having a strict subset of C++11's
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// unique_ptr<> features. Known deficiencies include not supporting move-only
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// deleteres, function pointers as deleters, and deleters with reference
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// deleters, function pointers as deleters, and deleters with reference
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// types.
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template <class T, class D = rtc::DefaultDeleter<T> >
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class scoped_ptr {
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RTC_MOVE_ONLY_TYPE_FOR_CPP_03(scoped_ptr, RValue)
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RTC_MOVE_ONLY_TYPE_WITH_MOVE_CONSTRUCTOR_FOR_CPP_03(scoped_ptr)
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// TODO(ajm): If we ever import RefCountedBase, this check needs to be
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// enabled.
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//static_assert(rtc::internal::IsNotRefCounted<T>::value,
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// "T is refcounted type and needs scoped refptr");
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public:
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// The element and deleter types.
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typedef T element_type;
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typedef D deleter_type;
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// Constructor. Defaults to initializing with NULL.
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scoped_ptr() : impl_(NULL) { }
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// Constructor. Defaults to initializing with nullptr.
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scoped_ptr() : impl_(nullptr) {}
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// Constructor. Takes ownership of p.
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explicit scoped_ptr(element_type* p) : impl_(p) {}
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@ -324,6 +344,9 @@ class scoped_ptr {
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// Constructor. Allows initialization of a stateful deleter.
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scoped_ptr(element_type* p, const D& d) : impl_(p, d) {}
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// Constructor. Allows construction from a nullptr.
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scoped_ptr(decltype(nullptr)) : impl_(nullptr) {}
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// Constructor. Allows construction from a scoped_ptr rvalue for a
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// convertible type and deleter.
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//
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@ -335,13 +358,11 @@ class scoped_ptr {
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// use of SFINAE. You only need to care about this if you modify the
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// implementation of scoped_ptr.
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template <typename U, typename V>
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scoped_ptr(scoped_ptr<U, V> other) : impl_(&other.impl_) {
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scoped_ptr(scoped_ptr<U, V>&& other)
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: impl_(&other.impl_) {
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static_assert(!rtc::is_array<U>::value, "U cannot be an array");
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}
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// Constructor. Move constructor for C++03 move emulation of this type.
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scoped_ptr(RValue rvalue) : impl_(&rvalue.object->impl_) { }
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// operator=. Allows assignment from a scoped_ptr rvalue for a convertible
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// type and deleter.
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//
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@ -353,24 +374,31 @@ class scoped_ptr {
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// You only need to care about this if you modify the implementation of
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// scoped_ptr.
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template <typename U, typename V>
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scoped_ptr& operator=(scoped_ptr<U, V> rhs) {
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scoped_ptr& operator=(scoped_ptr<U, V>&& rhs) {
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static_assert(!rtc::is_array<U>::value, "U cannot be an array");
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impl_.TakeState(&rhs.impl_);
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return *this;
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}
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// operator=. Allows assignment from a nullptr. Deletes the currently owned
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// object, if any.
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scoped_ptr& operator=(decltype(nullptr)) {
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reset();
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return *this;
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}
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// Reset. Deletes the currently owned object, if any.
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// Then takes ownership of a new object, if given.
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void reset(element_type* p = NULL) { impl_.reset(p); }
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void reset(element_type* p = nullptr) { impl_.reset(p); }
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// Accessors to get the owned object.
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// operator* and operator-> will assert() if there is no current object.
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element_type& operator*() const {
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ASSERT(impl_.get() != NULL);
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assert(impl_.get() != nullptr);
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return *impl_.get();
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}
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element_type* operator->() const {
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ASSERT(impl_.get() != NULL);
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assert(impl_.get() != nullptr);
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return impl_.get();
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}
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element_type* get() const { return impl_.get(); }
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@ -391,7 +419,9 @@ class scoped_ptr {
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scoped_ptr::*Testable;
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public:
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operator Testable() const { return impl_.get() ? &scoped_ptr::impl_ : NULL; }
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operator Testable() const {
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return impl_.get() ? &scoped_ptr::impl_ : nullptr;
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}
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// Comparison operators.
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// These return whether two scoped_ptr refer to the same object, not just to
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@ -405,10 +435,9 @@ class scoped_ptr {
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}
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// Release a pointer.
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// The return value is the current pointer held by this object.
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// If this object holds a NULL pointer, the return value is NULL.
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// After this operation, this object will hold a NULL pointer,
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// and will not own the object any more.
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// The return value is the current pointer held by this object. If this object
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// holds a nullptr, the return value is nullptr. After this operation, this
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// object will hold a nullptr, and will not own the object any more.
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element_type* release() WARN_UNUSED_RESULT {
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return impl_.release();
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}
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@ -424,17 +453,6 @@ class scoped_ptr {
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return impl_.use();
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}
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// C++98 doesn't support functions templates with default parameters which
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// makes it hard to write a PassAs() that understands converting the deleter
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// while preserving simple calling semantics.
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//
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// Until there is a use case for PassAs() with custom deleters, just ignore
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// the custom deleter.
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template <typename PassAsType>
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scoped_ptr<PassAsType> PassAs() {
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return scoped_ptr<PassAsType>(Pass());
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}
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private:
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// Needed to reach into |impl_| in the constructor.
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template <typename U, typename V> friend class scoped_ptr;
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@ -453,15 +471,15 @@ class scoped_ptr {
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template <class T, class D>
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class scoped_ptr<T[], D> {
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RTC_MOVE_ONLY_TYPE_FOR_CPP_03(scoped_ptr, RValue)
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RTC_MOVE_ONLY_TYPE_WITH_MOVE_CONSTRUCTOR_FOR_CPP_03(scoped_ptr)
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public:
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// The element and deleter types.
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typedef T element_type;
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typedef D deleter_type;
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// Constructor. Defaults to initializing with NULL.
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scoped_ptr() : impl_(NULL) { }
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// Constructor. Defaults to initializing with nullptr.
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scoped_ptr() : impl_(nullptr) {}
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// Constructor. Stores the given array. Note that the argument's type
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// must exactly match T*. In particular:
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@ -471,9 +489,6 @@ class scoped_ptr<T[], D> {
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// T and the derived types had different sizes access would be
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// incorrectly calculated). Deletion is also always undefined
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// (C++98 [expr.delete]p3). If you're doing this, fix your code.
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// - it cannot be NULL, because NULL is an integral expression, not a
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// pointer to T. Use the no-argument version instead of explicitly
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// passing NULL.
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// - it cannot be const-qualified differently from T per unique_ptr spec
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// (http://cplusplus.github.com/LWG/lwg-active.html#2118). Users wanting
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// to work around this may use implicit_cast<const T*>().
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@ -481,22 +496,32 @@ class scoped_ptr<T[], D> {
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// NOT use implicit_cast<Base*>() to upcast the static type of the array.
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explicit scoped_ptr(element_type* array) : impl_(array) {}
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// Constructor. Move constructor for C++03 move emulation of this type.
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scoped_ptr(RValue rvalue) : impl_(&rvalue.object->impl_) { }
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// Constructor. Allows construction from a nullptr.
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scoped_ptr(decltype(nullptr)) : impl_(nullptr) {}
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// operator=. Move operator= for C++03 move emulation of this type.
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scoped_ptr& operator=(RValue rhs) {
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impl_.TakeState(&rhs.object->impl_);
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// Constructor. Allows construction from a scoped_ptr rvalue.
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scoped_ptr(scoped_ptr&& other) : impl_(&other.impl_) {}
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// operator=. Allows assignment from a scoped_ptr rvalue.
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scoped_ptr& operator=(scoped_ptr&& rhs) {
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impl_.TakeState(&rhs.impl_);
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return *this;
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}
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// operator=. Allows assignment from a nullptr. Deletes the currently owned
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// array, if any.
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scoped_ptr& operator=(decltype(nullptr)) {
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reset();
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return *this;
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}
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// Reset. Deletes the currently owned array, if any.
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// Then takes ownership of a new object, if given.
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void reset(element_type* array = NULL) { impl_.reset(array); }
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void reset(element_type* array = nullptr) { impl_.reset(array); }
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// Accessors to get the owned array.
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element_type& operator[](size_t i) const {
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ASSERT(impl_.get() != NULL);
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assert(impl_.get() != nullptr);
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return impl_.get()[i];
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}
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element_type* get() const { return impl_.get(); }
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@ -512,7 +537,9 @@ class scoped_ptr<T[], D> {
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scoped_ptr::*Testable;
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public:
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operator Testable() const { return impl_.get() ? &scoped_ptr::impl_ : NULL; }
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operator Testable() const {
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return impl_.get() ? &scoped_ptr::impl_ : nullptr;
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}
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// Comparison operators.
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// These return whether two scoped_ptr refer to the same object, not just to
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@ -526,10 +553,9 @@ class scoped_ptr<T[], D> {
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}
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// Release a pointer.
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// The return value is the current pointer held by this object.
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// If this object holds a NULL pointer, the return value is NULL.
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// After this operation, this object will hold a NULL pointer,
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// and will not own the object any more.
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// The return value is the current pointer held by this object. If this object
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// holds a nullptr, the return value is nullptr. After this operation, this
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// object will hold a nullptr, and will not own the object any more.
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element_type* release() WARN_UNUSED_RESULT {
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return impl_.release();
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}
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@ -575,7 +601,6 @@ class scoped_ptr<T[], D> {
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} // namespace rtc
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// Free functions
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template <class T, class D>
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void swap(rtc::scoped_ptr<T, D>& p1, rtc::scoped_ptr<T, D>& p2) {
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p1.swap(p2);
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@ -591,4 +616,12 @@ bool operator!=(T* p1, const rtc::scoped_ptr<T, D>& p2) {
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return p1 != p2.get();
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}
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// A function to convert T* into scoped_ptr<T>
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// Doing e.g. make_scoped_ptr(new FooBarBaz<type>(arg)) is a shorter notation
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// for scoped_ptr<FooBarBaz<type> >(new FooBarBaz<type>(arg))
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template <typename T>
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rtc::scoped_ptr<T> rtc_make_scoped_ptr(T* ptr) {
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return rtc::scoped_ptr<T>(ptr);
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}
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#endif // #ifndef WEBRTC_BASE_SCOPED_PTR_H__
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