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-rw-r--r--libc/private/UniquePtr.h140
1 files changed, 140 insertions, 0 deletions
diff --git a/libc/private/UniquePtr.h b/libc/private/UniquePtr.h
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+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef UNIQUE_PTR_H_included
+#define UNIQUE_PTR_H_included
+
+// Default deleter for pointer types.
+template <typename T>
+struct DefaultDelete {
+ enum { type_must_be_complete = sizeof(T) };
+ DefaultDelete() {}
+ void operator()(T* p) const {
+ delete p;
+ }
+};
+
+// Default deleter for array types.
+template <typename T>
+struct DefaultDelete<T[]> {
+ enum { type_must_be_complete = sizeof(T) };
+ void operator()(T* p) const {
+ delete[] p;
+ }
+};
+
+// A smart pointer that deletes the given pointer on destruction.
+// Equivalent to C++0x's std::unique_ptr (a combination of boost::scoped_ptr
+// and boost::scoped_array).
+// Named to be in keeping with Android style but also to avoid
+// collision with any other implementation, until we can switch over
+// to unique_ptr.
+// Use thus:
+// UniquePtr<C> c(new C);
+template <typename T, typename D = DefaultDelete<T> >
+class UniquePtr {
+public:
+ // Construct a new UniquePtr, taking ownership of the given raw pointer.
+ explicit UniquePtr(T* ptr = nullptr) : mPtr(ptr) { }
+
+ UniquePtr(UniquePtr<T, D>&& that) {
+ mPtr = that.mPtr;
+ that.mPtr = nullptr;
+ }
+
+ ~UniquePtr() {
+ reset();
+ }
+
+ // Accessors.
+ T& operator*() const { return *mPtr; }
+ T* operator->() const { return mPtr; }
+ T* get() const { return mPtr; }
+
+ // Returns the raw pointer and hands over ownership to the caller.
+ // The pointer will not be deleted by UniquePtr.
+ T* release() __attribute__((warn_unused_result)) {
+ T* result = mPtr;
+ mPtr = nullptr;
+ return result;
+ }
+
+ // Takes ownership of the given raw pointer.
+ // If this smart pointer previously owned a different raw pointer, that
+ // raw pointer will be freed.
+ void reset(T* ptr = nullptr) {
+ if (ptr != mPtr) {
+ D()(mPtr);
+ mPtr = ptr;
+ }
+ }
+
+private:
+ // The raw pointer.
+ T* mPtr;
+
+ // Comparing unique pointers is probably a mistake, since they're unique.
+ template <typename T2> bool operator==(const UniquePtr<T2>& p) const = delete;
+ template <typename T2> bool operator!=(const UniquePtr<T2>& p) const = delete;
+
+ // Disallow copy and assignment.
+ UniquePtr(const UniquePtr&) = delete;
+ void operator=(const UniquePtr&) = delete;
+};
+
+// Partial specialization for array types. Like std::unique_ptr, this removes
+// operator* and operator-> but adds operator[].
+template <typename T, typename D>
+class UniquePtr<T[], D> {
+public:
+ explicit UniquePtr(T* ptr = NULL) : mPtr(ptr) {
+ }
+ UniquePtr(UniquePtr<T, D>&& that) {
+ mPtr = that.mPtr;
+ that.mPtr = nullptr;
+ }
+
+ ~UniquePtr() {
+ reset();
+ }
+
+ T& operator[](size_t i) const {
+ return mPtr[i];
+ }
+ T* get() const { return mPtr; }
+
+ T* release() __attribute__((warn_unused_result)) {
+ T* result = mPtr;
+ mPtr = NULL;
+ return result;
+ }
+
+ void reset(T* ptr = NULL) {
+ if (ptr != mPtr) {
+ D()(mPtr);
+ mPtr = ptr;
+ }
+ }
+
+private:
+ T* mPtr;
+
+ // Disallow copy and assignment.
+ UniquePtr(const UniquePtr&) = delete;
+ void operator=(const UniquePtr&) = delete;
+};
+
+#endif // UNIQUE_PTR_H_included