1 files changed, 197 insertions, 0 deletions
diff --git a/mojo/public/cpp/bindings/wtf_array.h b/mojo/public/cpp/bindings/wtf_array.h
new file mode 100644
index 0000000..46d9a69
--- /dev/null
+++ b/mojo/public/cpp/bindings/wtf_array.h
@@ -0,0 +1,197 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MOJO_PUBLIC_CPP_BINDINGS_WTF_ARRAY_H_
+#define MOJO_PUBLIC_CPP_BINDINGS_WTF_ARRAY_H_
+
+#include <stddef.h>
+#include <utility>
+
+#include "base/macros.h"
+#include "mojo/public/cpp/bindings/lib/array_internal.h"
+#include "mojo/public/cpp/bindings/lib/bindings_internal.h"
+#include "mojo/public/cpp/bindings/lib/template_util.h"
+#include "mojo/public/cpp/bindings/lib/wtf_clone_equals_util.h"
+#include "mojo/public/cpp/bindings/type_converter.h"
+#include "third_party/WebKit/Source/wtf/Vector.h"
+
+namespace mojo {
+
+// Represents an array backed by WTF::Vector. Comparing with WTF::Vector,
+// mojo::WTFArray is move-only and can be null.
+// It is easy to convert between WTF::Vector<T> and mojo::WTFArray<T>:
+//   - constructor WTFArray(WTF::Vector<T>&&) takes the contents of a
+//     WTF::Vector<T>;
+//   - method PassStorage() passes the underlying WTF::Vector.
+template <typename T>
+class WTFArray {
+ public:
+  // Constructs an empty array.
+  WTFArray() : is_null_(false) {}
+  // Constructs a null array.
+  WTFArray(std::nullptr_t null_pointer) : is_null_(true) {}
+
+  // Constructs a new non-null array of the specified size. The elements will
+  // be value-initialized (meaning that they will be initialized by their
+  // default constructor, if any, or else zero-initialized).
+  explicit WTFArray(size_t size) : vec_(size), is_null_(false) {}
+  ~WTFArray() {}
+
+  // Moves the contents of |other| into this array.
+  WTFArray(WTF::Vector<T>&& other) : vec_(std::move(other)), is_null_(false) {}
+  WTFArray(WTFArray&& other) : is_null_(true) { Take(&other); }
+
+  WTFArray& operator=(WTF::Vector<T>&& other) {
+    vec_ = std::move(other);
+    is_null_ = false;
+    return *this;
+  }
+  WTFArray& operator=(WTFArray&& other) {
+    Take(&other);
+    return *this;
+  }
+
+  WTFArray& operator=(std::nullptr_t null_pointer) {
+    is_null_ = true;
+    vec_.clear();
+    return *this;
+  }
+
+  // Creates a non-null array of the specified size. The elements will be
+  // value-initialized (meaning that they will be initialized by their default
+  // constructor, if any, or else zero-initialized).
+  static WTFArray New(size_t size) { return WTFArray(size); }
+
+  // Creates a new array with a copy of the contents of |other|.
+  template <typename U>
+  static WTFArray From(const U& other) {
+    return TypeConverter<WTFArray, U>::Convert(other);
+  }
+
+  // Copies the contents of this array to a new object of type |U|.
+  template <typename U>
+  U To() const {
+    return TypeConverter<U, WTFArray>::Convert(*this);
+  }
+
+  // Indicates whether the array is null (which is distinct from empty).
+  bool is_null() const {
+    // When the array is set to null, the underlying storage |vec_| shouldn't
+    // contain any elements.
+    DCHECK(!is_null_ || vec_.isEmpty());
+    return is_null_;
+  }
+
+  // Indicates whether the array is empty (which is distinct from null).
+  bool empty() const { return vec_.isEmpty() && !is_null_; }
+
+  // Returns a reference to the first element of the array. Calling this on a
+  // null or empty array causes undefined behavior.
+  const T& front() const { return vec_.first(); }
+  T& front() { return vec_.first(); }
+
+  // Returns the size of the array, which will be zero if the array is null.
+  size_t size() const { return vec_.size(); }
+
+  // Returns a reference to the element at zero-based |offset|. Calling this on
+  // an array with size less than |offset|+1 causes undefined behavior.
+  const T& at(size_t offset) const { return vec_.at(offset); }
+  const T& operator[](size_t offset) const { return at(offset); }
+  T& at(size_t offset) { return vec_.at(offset); }
+  T& operator[](size_t offset) { return at(offset); }
+
+  // Resizes the array to |size| and makes it non-null. Otherwise, works just
+  // like the resize method of |WTF::Vector|.
+  void resize(size_t size) {
+    is_null_ = false;
+    vec_.resize(size);
+  }
+
+  // Sets the array to empty (even if previously it was null.)
+  void SetToEmpty() { resize(0); }
+
+  // Returns a const reference to the |WTF::Vector| managed by this class. If
+  // the array is null, this will be an empty vector.
+  const WTF::Vector<T>& storage() const { return vec_; }
+
+  // Passes the underlying storage and resets this array to null.
+  //
+  // TODO(yzshen): Consider changing this to a rvalue-ref-qualified conversion
+  // to WTF::Vector<T> after we move to MSVC 2015.
+  WTF::Vector<T> PassStorage() {
+    is_null_ = true;
+    return std::move(vec_);
+  }
+
+  void Swap(WTFArray* other) {
+    std::swap(is_null_, other->is_null_);
+    vec_.swap(other->vec_);
+  }
+
+  // Swaps the contents of this array with the specified vector, making this
+  // array non-null. Since the vector cannot represent null, it will just be
+  // made empty if this array is null.
+  void Swap(WTF::Vector<T>* other) {
+    is_null_ = false;
+    vec_.swap(*other);
+  }
+
+  // Returns a copy of the array where each value of the new array has been
+  // "cloned" from the corresponding value of this array. If the element type
+  // defines a Clone() method, it will be used; otherwise copy
+  // constructor/assignment will be used.
+  //
+  // Please note that calling this method will fail compilation if the element
+  // type cannot be cloned (which usually means that it is a Mojo handle type or
+  // a type containing Mojo handles).
+  WTFArray Clone() const {
+    WTFArray result;
+    result.is_null_ = is_null_;
+    result.vec_ = internal::Clone(vec_);
+    return result;
+  }
+
+  // Indicates whether the contents of this array are equal to |other|. A null
+  // array is only equal to another null array. If the element type defines an
+  // Equals() method, it will be used; otherwise == operator will be used.
+  bool Equals(const WTFArray& other) const {
+    if (is_null() != other.is_null())
+      return false;
+    return internal::Equals(vec_, other.vec_);
+  }
+
+ private:
+  // TODO(dcheng): Use an explicit conversion operator.
+  typedef WTF::Vector<T> WTFArray::*Testable;
+
+ public:
+  operator Testable() const {
+    // When the array is set to null, the underlying storage |vec_| shouldn't
+    // contain any elements.
+    DCHECK(!is_null_ || vec_.isEmpty());
+    return is_null_ ? 0 : &WTFArray::vec_;
+  }
+
+ private:
+  // Forbid the == and != operators explicitly, otherwise WTFArray will be
+  // converted to Testable to do == or != comparison.
+  template <typename U>
+  bool operator==(const WTFArray<U>& other) const = delete;
+  template <typename U>
+  bool operator!=(const WTFArray<U>& other) const = delete;
+
+  void Take(WTFArray* other) {
+    operator=(nullptr);
+    Swap(other);
+  }
+
+  WTF::Vector<T> vec_;
+  bool is_null_;
+
+  DISALLOW_COPY_AND_ASSIGN(WTFArray);
+};
+
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_CPP_BINDINGS_WTF_ARRAY_H_