Cronet for iOS with C API for GRPC support.

components/cronet/ios/cronet_c_for_grpc.h

+// 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 COMPONENTS_CRONET_IOS_CRONET_C_FOR_GRPC_H_
+#define COMPONENTS_CRONET_IOS_CRONET_C_FOR_GRPC_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stddef.h>
+
+/* Cronet Engine API. */
+
+/* Opaque object representing Cronet Engine. Created and configured outside
+ * of this API to facilitate sharing with other components */
+typedef struct cronet_engine {
+  void* obj;
+  void* annotation;
+} cronet_engine;
+
+/* Cronet Bidirectional Stream API */
+
+/* Opaque object representing Cronet Bidirectional Stream. */
+typedef struct cronet_bidirectional_stream {
+  void* obj;
+  void* annotation;
+} cronet_bidirectional_stream;
+
+/* A single request or response header element. */
+typedef struct cronet_bidirectional_stream_header {
+  const char* key;
+  const char* value;
+} cronet_bidirectional_stream_header;
+
+/* Array of request or response headers or trailers. */
+typedef struct cronet_bidirectional_stream_header_array {
+  size_t count;
+  size_t capacity;
+  cronet_bidirectional_stream_header* headers;
+} cronet_bidirectional_stream_header_array;
+
+/* Set of callbacks used to receive callbacks from bidirectional stream. */
+typedef struct cronet_bidirectional_stream_callback {
+  /* Invoked when request headers are sent. Indicates that stream has initiated
+   * the request. Consumer may call cronet_bidirectional_stream_write() to start
+   * writing data.
+   */
+  void (*on_request_headers_sent)(cronet_bidirectional_stream* stream);
+
+  /* Invoked when initial response headers are received.
+   * Consumer must call cronet_bidirectional_stream_read() to start reading.
+   * Consumer may call cronet_bidirectional_stream_write() to start writing or
+   * close the stream. Contents of |headers| is valid for duration of the call.
+   */
+  void (*on_response_headers_received)(
+      cronet_bidirectional_stream* stream,
+      const cronet_bidirectional_stream_header_array* headers,
+      const char* negotiated_protocol);
+
+  /* Invoked when data is read into the buffer passed to
+   * cronet_bidirectional_stream_read(). Only part of the buffer may be
+   * populated. To continue reading, call cronet_bidirectional_stream_read().
+   * It may be invoked after on_response_trailers_received()}, if there was
+   * pending read data before trailers were received.
+   *
+   * If count is 0, it means the remote side has signaled that it will send no
+   * more data; future calls to cronet_bidirectional_stream_read() will result
+   * in the on_data_read() callback or on_succeded() callback if
+   * cronet_bidirectional_stream_write() was invoked with end_of_stream set to
+   * true.
+   */
+  void (*on_read_completed)(cronet_bidirectional_stream* stream,
+                            char* data,
+                            int count);

[xunjieli, 2016/04/13 15:28:24]

nit: Maybe use |bytes_read|, which is a little more descriptive? I didn't know
what |count|
is until I read the docs. 

[mef, 2016/04/14 14:07:24]

Done.

+
+  /**
+   * Invoked when all data passed to cronet_bidirectional_stream_write() is
+   * sent. To continue writing, call cronet_bidirectional_stream_write().
+   */
+  void (*on_write_completed)(cronet_bidirectional_stream* stream,
+                             const char* data);

[xunjieli, 2016/04/13 15:28:23]

Is this char* useful without knowing how long the data is?

[mef, 2016/04/14 14:07:24]

I think so, it lets the app know that buffer is ready to be freed/reused.

+
+  /* Invoked when trailers are received before closing the stream. Only invoked
+   * when server sends trailers, which it may not. May be invoked while there is
+   * read data remaining in local buffer. Contents of |trailers| is valid for
+   * duration of the call.
+   */
+  void (*on_response_trailers_received)(
+      cronet_bidirectional_stream* stream,
+      const cronet_bidirectional_stream_header_array* trailers);
+
+  /**
+   * Invoked when there is no data to be read or written and the stream is
+   * closed successfully remotely and locally. Once invoked, no further callback
+   * methods will be invoked.
+   */
+  void (*on_succeded)(cronet_bidirectional_stream* stream);
+
+  /**
+   * Invoked if the stream failed for any reason after
+   * cronet_bidirectional_stream_start(). HTTP/2 error codes are
+   * mapped to chrome net error codes. Once invoked, no further callback methods
+   * will be invoked.
+   */
+  void (*on_failed)(cronet_bidirectional_stream* stream, int net_error);
+
+  /**
+   * Invoked if the stream was canceled via
+   * cronet_bidirectional_stream_cancel(). Once invoked, no further callback
+   * methods will be invoked.
+   */
+  void (*on_canceled)(cronet_bidirectional_stream* stream);
+} cronet_bidirectional_stream_callback;
+
+/* Create a new stream object that uses |engine| and |callback|. All stream
+ * tasks are performed asynchronously on the |engine| network thread. |callback|
+ * methods are invoked synchronously on the |engine| network thread, but must
+ * not run tasks on the current thread to prevent blocking networking operations
+ * and causing exceptions during shutdown. The |annotation| is stored in
+ * bidirectional stream for arbitrary use by application.
+ *
+ * Returned |cronet_bidirectional_stream*| is owned by the caller, and must be
+ * destroyed using |cronet_bidirectional_stream_destroy|.
+ *
+ * Both |calback| and |engine| must remain valid until stream is destroyed.
+ */
+cronet_bidirectional_stream* cronet_bidirectional_stream_create(
+    cronet_engine* engine,
+    void* annotation,
+    cronet_bidirectional_stream_callback* callback);
+
+/* TBD: The following methods return int. Should it be a custom type? */
+
+/* Destroy stream object. Destroy could be called from any thread, including
+ * network thread, but is posted, so |stream| is valid until calling task is
+ * complete.
+ */
+int cronet_bidirectional_stream_destroy(cronet_bidirectional_stream* stream);
+
+/* Start the stream by sending request to |url| using |method| and |headers|. If
+ * |end_of_stream| is true, then no data is expected to be written. The |method|
+ * is HTTP verb, with PUT having a special meaning to mark idempotent request,
+ * which could use QUIC 0-RTT.
+ */
+int cronet_bidirectional_stream_start(
+    cronet_bidirectional_stream* stream,
+    const char* url,
+    int priority,
+    const char* method,
+    const cronet_bidirectional_stream_header_array* headers,
+    bool end_of_stream);
+
+/* Read response data into |buffer| of |capacity| length. Must only be called at
+ * most once in response to each invocation of the
+ * on_response_headers_received() and on_read_completed() methods of the
+ * cronet_bidirectional_stream_callback.
+ * Each call will result in an invocation of the callback's
+ * on_read_completed() method if data is read, or its on_failed() method if
+ * there's an error. The callback's on_succeeded() method is also invoked if
+ * there is no more data to read and |end_of_stream| was previously sent.
+ */
+int cronet_bidirectional_stream_read(cronet_bidirectional_stream* stream,
+                                     char* buffer,
+                                     int capacity);
+
+/* Write request data from |buffer| of |count| length. Must only be called at
+ * most once in response to each invocation of the
+ * on_request_headers_sent() and on_write_completed() methods of the
+ * cronet_bidirectional_stream_callback.
+ * Each call will result in an invocation the callback's on_write_completed()
+ * method if data is sent, or its on_failed() method if there's an error.
+ * The callback's on_succeeded() method is also invoked if |end_of_stream| is
+ * set and all response data has been read.
+ */
+int cronet_bidirectional_stream_write(cronet_bidirectional_stream* stream,
+                                      const char* buffer,
+                                      int count,

[xunjieli, 2016/04/13 15:28:23]

nit: Maybe use |buffer_length|, which is a little more descriptive? I didn't
know what |count| is until I read the docs. 

[mef, 2016/04/14 21:17:35]

Done.

+                                      bool end_of_stream);
+
+/* Cancels the stream. Can be called at any time after
+ * cronet_bidirectional_stream_start(). The on_canceled() method of
+ * cronet_bidirectional_stream_callback will be invoked when cancelation
+ * is complete and no further callback methods will be invoked. If the
+ * stream has completed or has not started, calling
+ * cronet_bidirectional_stream_cancel() has no effect and on_canceled() will not
+ * be invoked. At most one callback method may be invoked after
+ * cronet_bidirectional_stream_cancel() has completed.
+ */
+int cronet_bidirectional_stream_cancel(cronet_bidirectional_stream* stream);
+
+/* Returns true if the |stream| was successfully started and is now done
+ * (succeeded, canceled, or failed).
+ * Returns false if the |stream| stream is not yet started or is in progress.
+ */
+bool cronet_bidirectional_stream_is_done(cronet_bidirectional_stream* stream);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // COMPONENTS_CRONET_IOS_CRONET_C_FOR_GRPC_H_