[ON HOLD] Implement pull-based design for content decoding

net/filter/mock_stream_source.cc

+// 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.
+
+#include "net/filter/mock_stream_source.h"
+
+namespace net {
+
+MockStreamSource::MockStreamSource()
+    : StreamSource(StreamSource::SOURCE_NONE, nullptr),
+      awaiting_completion_(false),
+      dest_buffer_(nullptr),
+      dest_buffer_size_(0) {}
+
+MockStreamSource::~MockStreamSource() {}
+
+MockStreamSource::QueuedResult::QueuedResult(const char* data,
+                                             size_t len,
+                                             Error error,
+                                             bool sync)
+    : data(data), len(len), error(error), sync(sync) {}
+
+void MockStreamSource::AddReadResult(const char* data,
+                                     size_t len,
+                                     Error error,
+                                     bool sync) {
+  QueuedResult result(data, len, error, sync);
+  results_.push(result);
+}
+
+void MockStreamSource::CompleteNextRead() {
+  DCHECK(awaiting_completion_);
+  awaiting_completion_ = false;
+  QueuedResult r = results_.front();
+  DCHECK(!r.sync);
+  results_.pop();
+  DCHECK_GE(dest_buffer_size_, r.len);
+  memcpy(dest_buffer_->data(), r.data, r.len);
+  callback_.Run(r.error, r.len);
+}
+
+Error MockStreamSource::ReadInternal(IOBuffer* dest_buffer,
+                                     size_t buffer_size,
+                                     size_t* bytes_read) {
+  DCHECK(!awaiting_completion_);
+  if (results_.empty()) {
+    *bytes_read = 0;
+    return OK;
+  }
+
+  QueuedResult r = results_.front();
+  if (!r.sync) {
+    awaiting_completion_ = true;
+    dest_buffer_ = dest_buffer;
+    dest_buffer_size_ = buffer_size;
+    return ERR_IO_PENDING;
+  }
+
+  results_.pop();
+  DCHECK_GE(buffer_size, r.len);
+  memcpy(dest_buffer->data(), r.data, r.len);
+  *bytes_read = r.len;
+  return r.error;
+}
+
+}  // namespace net