DevTools: provide an option to return traces as streams

content/browser/devtools/protocol/io_handler.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 "content/browser/devtools/protocol/io_handler.h"
+
+#include <stdint.h>
+
+#include "base/bind.h"
+#include "base/files/file.h"
+#include "base/files/file_util.h"
+#include "base/memory/ref_counted_delete_on_message_loop.h"
+#include "base/memory/ref_counted_memory.h"
+#include "base/strings/string_number_conversions.h"
+#include "content/browser/devtools/devtools_io_context.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace content {
+namespace devtools {
+namespace io {
+
+using Response = DevToolsProtocolClient::Response;
+
+IOHandler::IOHandler(DevToolsIOContext* io_context)
+    : io_context_(io_context)
+    , weak_factory_(this) {}
+
+IOHandler::~IOHandler() {}
+
+void IOHandler::SetClient(scoped_ptr<Client> client) {
+  client_.swap(client);
+}
+
+Response IOHandler::Read(DevToolsCommandId command_id, const std::string& id,
+                         const int* offset, const int* max_size) {
+  static const size_t kDefaultChunkSize = 10 * 1024 * 1024;
+
+  scoped_refptr<DevToolsIOContext::Stream> stream = io_context_->GetById(id);
+  if (!stream)
+    return Response::InvalidParams("id");
+  stream->Read(offset ? *offset : -1,
+               max_size && *max_size ? *max_size : kDefaultChunkSize,
+               base::Bind(&IOHandler::ReadComplete,
+                          weak_factory_.GetWeakPtr(), command_id));
+  return Response::OK();
+}
+
+void IOHandler::ReadComplete(DevToolsCommandId command_id,
+                             const scoped_refptr<base::RefCountedString>& data,
+                             int status) {
+  if (status == DevToolsIOContext::Stream::StatusFailure) {

[pfeldman, 2015/08/24 18:17:55]

Close upon failure?

+    client_->SendError(command_id, Response::ServerError("Read failed"));
+    return;
+  }
+  bool eof = status == DevToolsIOContext::Stream::StatusEOF;
+  client_->SendReadResponse(command_id,
+      ReadResponse::Create()->set_data(data->data())->set_eof(eof));
+}
+
+Response IOHandler::Close(const std::string& id) {
+  return io_context_->Close(id) ? Response::OK()
+                                : Response::InvalidParams("id");
+}
+
+}  // namespace io
+}  // namespace devtools
+}  // namespace content