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inspector: stop relying on magic strings
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Inspector uses magical strings to communicate some events between
main thread and transport thread. This change replaces those strings
with enums that are more mainatainable (and remove unnecessary
encodings/decodings)

PR-URL: nodejs#10159
Reviewed-By: Ben Noordhuis <[email protected]>
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@italoacasas
Eugene Ostroukhov authored and italoacasas committed Jan 30, 2017
1 parent e30e307 commit 2d08bba
Showing 1 changed file with 61 additions and 45 deletions.
106 changes: 61 additions & 45 deletions src/inspector_agent.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@

#include <map>
#include <sstream>
#include <tuple>
#include <unicode/unistr.h>

#include <string.h>
Expand All @@ -30,9 +31,6 @@ namespace {
using v8_inspector::StringBuffer;
using v8_inspector::StringView;

const char TAG_CONNECT[] = "#connect";
const char TAG_DISCONNECT[] = "#disconnect";

static const uint8_t PROTOCOL_JSON[] = {
#include "v8_inspector_protocol_json.h" // NOLINT(build/include_order)
};
Expand Down Expand Up @@ -105,6 +103,14 @@ std::unique_ptr<StringBuffer> Utf8ToStringView(const std::string& message) {

class V8NodeInspector;

enum class InspectorAction {
kStartSession, kEndSession, kSendMessage
};

enum class TransportAction {
kSendMessage, kStop
};

class InspectorAgentDelegate: public node::inspector::SocketServerDelegate {
public:
InspectorAgentDelegate(AgentImpl* agent, const std::string& script_path,
Expand Down Expand Up @@ -143,14 +149,16 @@ class AgentImpl {
void FatalException(v8::Local<v8::Value> error,
v8::Local<v8::Message> message);

void PostIncomingMessage(int session_id, const std::string& message);
void PostIncomingMessage(InspectorAction action, int session_id,
const std::string& message);
void ResumeStartup() {
uv_sem_post(&start_sem_);
}

private:
template <typename Action>
using MessageQueue =
std::vector<std::pair<int, std::unique_ptr<StringBuffer>>>;
std::vector<std::tuple<Action, int, std::unique_ptr<StringBuffer>>>;
enum class State { kNew, kAccepting, kConnected, kDone, kError };

static void ThreadCbIO(void* agent);
Expand All @@ -161,10 +169,13 @@ class AgentImpl {
void WorkerRunIO();
void SetConnected(bool connected);
void DispatchMessages();
void Write(int session_id, const StringView& message);
bool AppendMessage(MessageQueue* vector, int session_id,
std::unique_ptr<StringBuffer> buffer);
void SwapBehindLock(MessageQueue* vector1, MessageQueue* vector2);
void Write(TransportAction action, int session_id, const StringView& message);
template <typename ActionType>
bool AppendMessage(MessageQueue<ActionType>* vector, ActionType action,
int session_id, std::unique_ptr<StringBuffer> buffer);
template <typename ActionType>
void SwapBehindLock(MessageQueue<ActionType>* vector1,
MessageQueue<ActionType>* vector2);
void WaitForFrontendMessage();
void NotifyMessageReceived();
State ToState(State state);
Expand All @@ -185,8 +196,8 @@ class AgentImpl {
uv_async_t io_thread_req_;
V8NodeInspector* inspector_;
v8::Platform* platform_;
MessageQueue incoming_message_queue_;
MessageQueue outgoing_message_queue_;
MessageQueue<InspectorAction> incoming_message_queue_;
MessageQueue<TransportAction> outgoing_message_queue_;
bool dispatching_messages_;
int session_id_;
InspectorSocketServer* server_;
Expand Down Expand Up @@ -236,7 +247,7 @@ class ChannelImpl final : public v8_inspector::V8Inspector::Channel {
void flushProtocolNotifications() override { }

void sendMessageToFrontend(const StringView& message) {
agent_->Write(agent_->session_id_, message);
agent_->Write(TransportAction::kSendMessage, agent_->session_id_, message);
}

AgentImpl* const agent_;
Expand Down Expand Up @@ -444,9 +455,7 @@ bool AgentImpl::IsStarted() {
void AgentImpl::WaitForDisconnect() {
if (state_ == State::kConnected) {
shutting_down_ = true;
// Gives a signal to stop accepting new connections
// TODO(eugeneo): Introduce an API with explicit request names.
Write(0, StringView());
Write(TransportAction::kStop, 0, StringView());
fprintf(stderr, "Waiting for the debugger to disconnect...\n");
fflush(stderr);
inspector_->runMessageLoopOnPause(0);
Expand Down Expand Up @@ -521,15 +530,17 @@ void AgentImpl::ThreadCbIO(void* agent) {
// static
void AgentImpl::WriteCbIO(uv_async_t* async) {
AgentImpl* agent = static_cast<AgentImpl*>(async->data);
MessageQueue outgoing_messages;
MessageQueue<TransportAction> outgoing_messages;
agent->SwapBehindLock(&agent->outgoing_message_queue_, &outgoing_messages);
for (const MessageQueue::value_type& outgoing : outgoing_messages) {
StringView view = outgoing.second->string();
if (view.length() == 0) {
for (const auto& outgoing : outgoing_messages) {
switch (std::get<0>(outgoing)) {
case TransportAction::kStop:
agent->server_->Stop(nullptr);
} else {
agent->server_->Send(outgoing.first,
StringViewToUtf8(outgoing.second->string()));
break;
case TransportAction::kSendMessage:
std::string message = StringViewToUtf8(std::get<2>(outgoing)->string());
agent->server_->Send(std::get<1>(outgoing), message);
break;
}
}
}
Expand Down Expand Up @@ -573,22 +584,26 @@ void AgentImpl::WorkerRunIO() {
server_ = nullptr;
}

bool AgentImpl::AppendMessage(MessageQueue* queue, int session_id,
template <typename ActionType>
bool AgentImpl::AppendMessage(MessageQueue<ActionType>* queue,
ActionType action, int session_id,
std::unique_ptr<StringBuffer> buffer) {
Mutex::ScopedLock scoped_lock(state_lock_);
bool trigger_pumping = queue->empty();
queue->push_back(std::make_pair(session_id, std::move(buffer)));
queue->push_back(std::make_tuple(action, session_id, std::move(buffer)));
return trigger_pumping;
}

void AgentImpl::SwapBehindLock(MessageQueue* vector1, MessageQueue* vector2) {
template <typename ActionType>
void AgentImpl::SwapBehindLock(MessageQueue<ActionType>* vector1,
MessageQueue<ActionType>* vector2) {
Mutex::ScopedLock scoped_lock(state_lock_);
vector1->swap(*vector2);
}

void AgentImpl::PostIncomingMessage(int session_id,
void AgentImpl::PostIncomingMessage(InspectorAction action, int session_id,
const std::string& message) {
if (AppendMessage(&incoming_message_queue_, session_id,
if (AppendMessage(&incoming_message_queue_, action, session_id,
Utf8ToStringView(message))) {
v8::Isolate* isolate = parent_env_->isolate();
platform_->CallOnForegroundThread(isolate,
Expand Down Expand Up @@ -617,25 +632,21 @@ void AgentImpl::DispatchMessages() {
if (dispatching_messages_)
return;
dispatching_messages_ = true;
MessageQueue tasks;
MessageQueue<InspectorAction> tasks;
do {
tasks.clear();
SwapBehindLock(&incoming_message_queue_, &tasks);
for (const MessageQueue::value_type& pair : tasks) {
StringView message = pair.second->string();
std::string tag;
if (message.length() == sizeof(TAG_CONNECT) - 1 ||
message.length() == sizeof(TAG_DISCONNECT) - 1) {
tag = StringViewToUtf8(message);
}

if (tag == TAG_CONNECT) {
for (const auto& task : tasks) {
StringView message = std::get<2>(task)->string();
switch (std::get<0>(task)) {
case InspectorAction::kStartSession:
CHECK_EQ(State::kAccepting, state_);
session_id_ = pair.first;
session_id_ = std::get<1>(task);
state_ = State::kConnected;
fprintf(stderr, "Debugger attached.\n");
inspector_->connectFrontend();
} else if (tag == TAG_DISCONNECT) {
break;
case InspectorAction::kEndSession:
CHECK_EQ(State::kConnected, state_);
if (shutting_down_) {
state_ = State::kDone;
Expand All @@ -644,16 +655,19 @@ void AgentImpl::DispatchMessages() {
}
inspector_->quitMessageLoopOnPause();
inspector_->disconnectFrontend();
} else {
break;
case InspectorAction::kSendMessage:
inspector_->dispatchMessageFromFrontend(message);
break;
}
}
} while (!tasks.empty());
dispatching_messages_ = false;
}

void AgentImpl::Write(int session_id, const StringView& inspector_message) {
AppendMessage(&outgoing_message_queue_, session_id,
void AgentImpl::Write(TransportAction action, int session_id,
const StringView& inspector_message) {
AppendMessage(&outgoing_message_queue_, action, session_id,
StringBuffer::create(inspector_message));
int err = uv_async_send(&io_thread_req_);
CHECK_EQ(0, err);
Expand Down Expand Up @@ -710,7 +724,8 @@ bool InspectorAgentDelegate::StartSession(int session_id,
if (connected_)
return false;
connected_ = true;
agent_->PostIncomingMessage(session_id, TAG_CONNECT);
session_id_++;
agent_->PostIncomingMessage(InspectorAction::kStartSession, session_id, "");
return true;
}

Expand All @@ -727,12 +742,13 @@ void InspectorAgentDelegate::MessageReceived(int session_id,
agent_->ResumeStartup();
}
}
agent_->PostIncomingMessage(session_id, message);
agent_->PostIncomingMessage(InspectorAction::kSendMessage, session_id,
message);
}

void InspectorAgentDelegate::EndSession(int session_id) {
connected_ = false;
agent_->PostIncomingMessage(session_id, TAG_DISCONNECT);
agent_->PostIncomingMessage(InspectorAction::kEndSession, session_id, "");
}

std::vector<std::string> InspectorAgentDelegate::GetTargetIds() {
Expand Down

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