Added ImagePipe

mojo/services/gfx/images/cpp/image_pipe_producer_endpoint.h

+// Copyright 2015 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_SERVICES_GFX_IMAGES_INTERFACES_IMAGE_PIPE_PRODUCER_ENDPOINT_H_
+#define MOJO_SERVICES_GFX_IMAGES_INTERFACES_IMAGE_PIPE_PRODUCER_ENDPOINT_H_
+
+#include "image_pipe_endpoint.h"
+#include "mojo/public/c/system/macros.h"
+#include "mojo/services/gfx/images/interfaces/image_pipe.mojom.h"
+
+namespace image_pipe {
+
+// This class wraps the producer end of an ImagePipe and validates the sanity
+// of both the producer actions and the consumer actions coming over the
+// message pipe. It also tracks the state of Images in the pipe's image pool
+// and provides conviennce mechanisms for accessing this state (like the ability
+// to get the ID of an available image without having to manually track the
+// lifecycle of these images.
+class ImagePipeProducerEndpoint : public mojo::gfx::ImagePipe {
+ public:
+  ImagePipeProducerEndpoint(mojo::gfx::ImagePipePtr image_pipe,
+                            std::function<void()> endpoint_closed_callback);
+
+  ~ImagePipeProducerEndpoint() override;
+
+  // ask the endpoint for an available image to draw into

[jamesr, 2016/02/18 20:40:59]

capitalize

[Forrest Reiling, 2016/02/25 00:35:14]

Done.

+  // returns false if no images are available, otherwise returns true and
+  // sets |id| to the acquired ID.
+  bool AcquireImage(uint32_t& id);

[jamesr, 2016/02/18 20:40:59]

pointer for out-param

[Forrest Reiling, 2016/02/25 00:35:15]

Done.

+
+  // The blocking version of the above function. This function will block until
+  // an Image is available or the deadline is met. If there are no images in the
+  // pool or the underlying message pipe has errors then false will be returned
+  bool AcquireImageBlocking(uint32_t& id, MojoDeadline deadline);
+
+  // Inherited from mojo::gfx::ImagePipe, see image_pipe.mojom for comments
+  void AddImage(mojo::gfx::ImagePtr image, uint32_t id) override;
+  void RemoveImage(uint32_t id) override;
+  void PresentImage(uint32_t id, const PresentImageCallback& callback) override;
+  void FlushImages() override;
+  void GetSupportedImageProperties(
+      const GetSupportedImagePropertiesCallback& callback) override;
+
+  // returns true iff the message pipe underlying the image pipe has enountered

[jamesr, 2016/02/18 20:40:59]

we don't normally say "iff" even when we mean it

[Forrest Reiling, 2016/02/25 00:35:15]

Sure. For the record though I'm pretty sure if you're reading header comments
you probably know what iff means and can infer from context that its not a typo.

+  // errors or closed
+  bool HasEncounteredError();
+
+  // For testing only, makes fatal errors not quite fatal, which allows tests
+  // to cause a fatal error and check that it was caught correctly without
+  // dying a horrible death in the process. If you are using this for something
+  // other than testing you are probably doing something very wrong.
+  void DisableFatalErrors();
+
+ private:
+  void CloseEndpoint();
+
+  // This exists wrap ImagePipeEndpoint::ConsumerRelease because for some reason
+  // GCC doesnt like us calling protected methods on our base class from inside
+  // a lambda that captures 'this', which breaks the fnl build. Clang handles it
+  // fine, but its unclear whos right here, so we trampoline it as a workaround
+  void ConsumerReleaseInternal(uint32_t id,
+                               mojo::gfx::PresentationStatus status);
+
+  ImagePipeEndpoint state_tacker_;

[jamesr, 2016/02/18 20:40:59]

tacker -> tracker? or is this something else? i'm not sure what a "tacker" is

[Forrest Reiling, 2016/02/25 00:35:15]

'tacker' is typo-copy-pasta cancer. Fixed

+  mojo::gfx::ImagePipePtr image_pipe_ptr_;
+  std::function<void()> endpoint_closed_callback_;
+};
+}

[jamesr, 2016/02/18 20:40:59]

newline, comment

[Forrest Reiling, 2016/02/25 00:35:14]

Done.

+
+#endif  // MOJO_SERVICES_GFX_IMAGES_INTERFACES_IMAGE_PIPE_PRODUCER_ENDPOINT_H_