make ipc easier to use

.vscode/settings.json

@@ -0,0 +1,18 @@
+{
+  "files.associations": {
+    "*.script": "pascal",
+    "functional": "cpp",
+    "queue": "cpp",
+    "stack": "cpp",
+    "tuple": "cpp",
+    "xutility": "cpp",
+    "xlocale": "cpp"
+  },
+  "files.exclude": {
+    "**/.git": true,
+    "**/.svn": true,
+    "**/.hg": true,
+    "**/.DS_Store": true,
+    "third_party/": true
+  }
+}

command_line.cc

@@ -97,11 +97,10 @@ indexer.exe --index-file /work2/chrome/src/chrome/foo.cc
 #include "ipc.h"
 
 void IndexerServerMain() {
-  IpcMessageQueue to_server("indexer_to_server");
-  IpcMessageQueue to_client("indexer_to_language_client");
+  IpcServer ipc("language_server");
 
   while (true) {
-    std::vector<std::unique_ptr<BaseIpcMessage>> messages = to_server.PopMessage();
+    std::vector<std::unique_ptr<BaseIpcMessage>> messages = ipc.TakeMessages();
 
     std::cout << "Server has " << messages.size() << " messages" << std::endl;
     for (auto& message : messages) {
@@ -109,7 +108,7 @@ void IndexerServerMain() {
       case JsonMessage::Kind::IsAlive:
       {
         IpcMessage_IsAlive response;
-        to_client.PushMessage(&response);
+        ipc.SendToClient(0, &response); // todo: make non-blocking
         break;
       }
       default:
@@ -125,24 +124,19 @@ void IndexerServerMain() {
 }
 
 void LanguageServerMain() {
-  // TODO: Encapsulate this pattern (ie, we generally want bi-directional channel/queue)
-  // TODO: Rename IpcMessageQueue to IpcDirectionalChannel
-  //       - As per above, introduce wrapper IpcBidirectionalChannel that has two IpcDirectionalChannel instances
-
-  IpcMessageQueue to_server("indexer_to_server");
-  IpcMessageQueue to_client("indexer_to_language_client");
+  IpcClient ipc("language_server", 0);
 
   // Discard any left-over messages from previous runs.
-  to_client.PopMessage();
+  ipc.TakeMessages();
 
   // Emit an alive check. Sleep so the server has time to respond.
   IpcMessage_IsAlive check_alive;
-  to_server.PushMessage(&check_alive);
+  ipc.SendToServer(&check_alive);
   using namespace std::chrono_literals;
   std::this_thread::sleep_for(50ms); // TODO: Tune this value or make it configurable.
 
   // Check if we got an IsAlive message back.
-  std::vector<std::unique_ptr<BaseIpcMessage>> messages = to_client.PopMessage();
+  std::vector<std::unique_ptr<BaseIpcMessage>> messages = ipc.TakeMessages();
   bool has_server = false;
   for (auto& message : messages) {
     if (message->kind == JsonMessage::Kind::IsAlive) {

ipc.cc

@@ -4,6 +4,14 @@ namespace {
   JsonMessage* as_message(char* ptr) {
     return reinterpret_cast<JsonMessage*>(ptr);
   }
+
+  std::string NameToServerName(const std::string& name) {
+    return name + "_server";
+  }
+
+  std::string NameToClientName(const std::string& name, int client_id) {
+    return name + "_server_" + std::to_string(client_id);
+  }
 }
 
 const char* JsonMessage::payload() {
@@ -52,17 +60,17 @@ void IpcMessage_CreateIndex::Deserialize(Reader& reader) {
   ::Deserialize(reader, "args", args);
 }
 
-IpcMessageQueue::IpcMessageQueue(const std::string& name) {
+IpcDirectionalChannel::IpcDirectionalChannel(const std::string& name) {
   local_block = new char[shmem_size];
   shared = CreatePlatformSharedMemory(name + "_memory");
   mutex = CreatePlatformMutex(name + "_mutex");
 }
 
-IpcMessageQueue::~IpcMessageQueue() {
+IpcDirectionalChannel::~IpcDirectionalChannel() {
   delete[] local_block;
 }
 
-void IpcMessageQueue::PushMessage(BaseIpcMessage* message) {
+void IpcDirectionalChannel::PushMessage(BaseIpcMessage* message) {
   rapidjson::StringBuffer output;
   rapidjson::PrettyWriter<rapidjson::StringBuffer> writer(output);
   writer.SetFormatOptions(
@@ -103,7 +111,7 @@ void IpcMessageQueue::PushMessage(BaseIpcMessage* message) {
 
 }
 
-std::vector<std::unique_ptr<BaseIpcMessage>> IpcMessageQueue::PopMessage() {
+std::vector<std::unique_ptr<BaseIpcMessage>> IpcDirectionalChannel::TakeMessages() {
   size_t remaining_bytes = 0;
   // Move data from shared memory into a local buffer. Do this
   // before parsing the blocks so that other processes can begin
@@ -150,4 +158,33 @@ std::vector<std::unique_ptr<BaseIpcMessage>> IpcMessageQueue::PopMessage() {
   }
 
   return result;
+}
+
+
+
+IpcServer::IpcServer(const std::string& name)
+  : name_(name), server_(NameToServerName(name)) {}
+
+void IpcServer::SendToClient(int client_id, BaseIpcMessage* message) {
+  // Find or create the client.
+  auto it = clients_.find(client_id);
+  if (it == clients_.end())
+    clients_[client_id] = std::make_unique<IpcDirectionalChannel>(NameToClientName(name_, client_id));
+
+  clients_[client_id]->PushMessage(message);
+}
+
+std::vector<std::unique_ptr<BaseIpcMessage>> IpcServer::TakeMessages() {
+  return server_.TakeMessages();
+}
+
+IpcClient::IpcClient(const std::string& name, int client_id)
+  : server_(NameToServerName(name)), client_(NameToClientName(name, client_id)) {}
+
+void IpcClient::SendToServer(BaseIpcMessage* message) {
+  server_.PushMessage(message);
+}
+
+std::vector<std::unique_ptr<BaseIpcMessage>> IpcClient::TakeMessages() {
+  return client_.TakeMessages();
 }

ipc.h

@@ -72,15 +72,15 @@ struct IpcMessage_CreateIndex : public BaseIpcMessage {
   void Deserialize(Reader& reader) override;
 };
 
-struct IpcMessageQueue {
+struct IpcDirectionalChannel {
   // NOTE: We keep all pointers in terms of char* so pointer arithmetic is
   // always relative to bytes.
 
-  explicit IpcMessageQueue(const std::string& name);
-  ~IpcMessageQueue();
+  explicit IpcDirectionalChannel(const std::string& name);
+  ~IpcDirectionalChannel();
 
   void PushMessage(BaseIpcMessage* message);
-  std::vector<std::unique_ptr<BaseIpcMessage>> PopMessage();
+  std::vector<std::unique_ptr<BaseIpcMessage>> TakeMessages();
 
 private:
   JsonMessage* get_free_message() {
@@ -93,4 +93,27 @@ private:
 
   // Pointer to process-local memory.
   char* local_block;
+};
+
+struct IpcServer {
+  IpcServer(const std::string& name);
+
+  void SendToClient(int client_id, BaseIpcMessage* message);
+  std::vector<std::unique_ptr<BaseIpcMessage>> TakeMessages();
+
+private:
+  std::string name_;
+  IpcDirectionalChannel server_;
+  std::unordered_map<int, std::unique_ptr<IpcDirectionalChannel>> clients_;
+};
+
+struct IpcClient {
+  IpcClient(const std::string& name, int client_id);
+
+  void SendToServer(BaseIpcMessage* message);
+  std::vector<std::unique_ptr<BaseIpcMessage>> TakeMessages();
+
+private:
+  IpcDirectionalChannel server_;
+  IpcDirectionalChannel client_;
 };

shared_memory_win.cpp

@@ -1,50 +0,0 @@
-#include <iostream>
-#include <vector>
-#include <memory>
-
-#include "ipc.h"
-
-
-
-int main525252(int argc, char** argv) {
-  if (argc == 2) {
-    IpcMessageQueue queue("myqueue");
-    int i = 0;
-    while (true) {
-      IpcMessage_ImportIndex m;
-      m.path = "foo #" + std::to_string(i);
-      queue.PushMessage(&m);
-      std::cout << "Sent " << i << std::endl;;
-
-      using namespace std::chrono_literals;
-      std::this_thread::sleep_for(10ms);
-
-      ++i;
-    }
-  }
-
-  else {
-    IpcMessageQueue queue("myqueue");
-
-    while (true) {
-      std::vector<std::unique_ptr<BaseIpcMessage>> messages = queue.PopMessage();
-      std::cout << "Got " << messages.size() << " messages" << std::endl;
-
-      for (auto& message : messages) {
-        rapidjson::StringBuffer output;
-        rapidjson::PrettyWriter<rapidjson::StringBuffer> writer(output);
-        writer.SetFormatOptions(
-          rapidjson::PrettyFormatOptions::kFormatSingleLineArray);
-        writer.SetIndent(' ', 2);
-        message->Serialize(writer);
-
-        std::cout << "  kind=" << static_cast<int>(message->kind) << ", json=" << output.GetString() << std::endl;
-      }
-
-      using namespace std::chrono_literals;
-      std::this_thread::sleep_for(5s);
-    }
-  }
-
-  return 0;
-}