partial messages work

command_line.cc

@@ -663,27 +663,24 @@ void LanguageServerMain(std::string process_name) {
 
   std::thread stdio_reader(&LanguageServerStdinLoop, &client_ipc);
 
-
-  // No server. Run it in-process.
   if (!has_server) {
-
-    QueryableDatabase db;
-    IpcServer server_ipc("languageserver");
-
-    while (true) {
-      QueryDbMainLoop(&server_ipc, &db);
-      LanguageServerMainLoop(&client_ipc);
-      // TODO: use a condition variable.
-      std::this_thread::sleep_for(std::chrono::milliseconds(20));
-    }
+    // No server. Run it in-process.
+    new std::thread([&]() {
+      IpcServer server_ipc("languageserver");
+      QueryableDatabase db;
+      while (true) {
+        QueryDbMainLoop(&server_ipc, &db);
+        // TODO: use a condition variable.
+        std::this_thread::sleep_for(std::chrono::microseconds(0));
+      }
+    });
   }
 
-  else {
-    while (true) {
-      LanguageServerMainLoop(&client_ipc);
-      // TODO: use a condition variable.
-      std::this_thread::sleep_for(std::chrono::milliseconds(20));
-    }
+  // Run language client.
+  while (true) {
+    LanguageServerMainLoop(&client_ipc);
+    // TODO: use a condition variable.
+    std::this_thread::sleep_for(std::chrono::microseconds(0));
   }
 }
 
@@ -734,6 +731,10 @@ void LanguageServerMain(std::string process_name) {
 
 
 int main(int argc, char** argv) {
+  bool loop = false;
+  while (loop)
+    std::this_thread::sleep_for(std::chrono::milliseconds(16));
+
   if (argc == 1) {
     RunTests();
     return 0;

ipc.cc

@@ -2,44 +2,9 @@
 #include "serializer.h"
 
 namespace {
-  struct BufferBuilder {
-    void* memory;
-    size_t size;
-    size_t capacity;
-
-    BufferBuilder() {
-      memory = malloc(128);
-      size = 0;
-      capacity = 128;
-    }
-
-    ~BufferBuilder() {
-      free(memory);
-      size = 0;
-      capacity = 0;
-    }
-
-    void AppendToBuffer(void* content, size_t content_size) {
-      if (size + content_size > capacity) {
-        // Grow memory if needed.
-        size_t new_size = capacity * 2;
-        while (new_size < size + content_size)
-          new_size *= 2;
-        void* new_memory = malloc(capacity);
-        memcpy(new_memory, memory, size);
-        free(memory);
-        memory = new_memory;
-
-        // Append new content into memory.
-        memcpy((char*)memory + size, content, content_size);
-        size += content_size;
-      }
-    }
-
-    void Reset() {
-      size = 0;
-    }
-  };
+  // The absolute smallest partial payload we should send. This must be >0, ie, 1 is the
+  // minimum. Keep a reasonably high value so we don't send needlessly send tiny payloads.
+  const int kMinimumPartialPayloadSize = 128;
 
   // JSON-encoded message that is passed across shared memory.
   //
@@ -49,14 +14,20 @@ namespace {
   // completely different address.
   struct JsonMessage {
     IpcId ipc_id;
+    int partial_message_id;
+    bool has_more_chunks;
     size_t payload_size;
-
-    const char* payload() {
-      return reinterpret_cast<const char*>(this) + sizeof(JsonMessage);
+    void* payload() {
+      return reinterpret_cast<char*>(this) + sizeof(JsonMessage);
     }
-    void SetPayload(size_t payload_size, const char* payload) {
-      char* payload_dest = reinterpret_cast<char*>(this) + sizeof(JsonMessage);
+
+    void Setup(IpcId ipc_id, int partial_message_id, bool has_more_chunks, size_t payload_size, const char* payload) {
+      this->ipc_id = ipc_id;
+      this->partial_message_id = partial_message_id;
+      this->has_more_chunks = has_more_chunks;
       this->payload_size = payload_size;
+
+      char* payload_dest = reinterpret_cast<char*>(this) + sizeof(JsonMessage);
       memcpy(payload_dest, payload, payload_size);
     }
   };
@@ -89,15 +60,10 @@ struct IpcDirectionalChannel::MessageBuffer {
   size_t real_buffer_size;
 
   template<typename T>
-  T* Offset(size_t offset) {
+  T* Offset(size_t offset) const {
     return reinterpret_cast<T*>(static_cast<char*>(real_buffer) + offset);
   }
 
-  // Number of bytes available in buffer_start. Note that this
-  // is smaller than the total buffer size, since there is some
-  // metadata stored at the start of the buffer.
-  size_t buffer_size;
-
   struct Metadata {
     // The number of bytes that are currently used in the buffer minus the
     // size of this Metadata struct.
@@ -106,22 +72,26 @@ struct IpcDirectionalChannel::MessageBuffer {
     int num_outstanding_partial_messages = 0;
   };
 
-  Metadata* metadata() {
+  Metadata* metadata() const {
     return Offset<Metadata>(0);
   }
 
-  JsonMessage* message_at_offset(size_t offset) {
+  size_t bytes_available() const {
+    return real_buffer_size - sizeof(Metadata) - metadata()->bytes_used;
+  }
+
+  JsonMessage* message_at_offset(size_t offset) const {
     return Offset<JsonMessage>(sizeof(Metadata) + offset);
   }
 
   // First json message.
-  JsonMessage* first_message() {
+  JsonMessage* first_message() const {
     return message_at_offset(0);
   }
 
   // First free, writable json message. Make sure to increase *bytes_used()
   // by any written size.
-  JsonMessage* free_message() {
+  JsonMessage* free_message() const {
     return message_at_offset(metadata()->bytes_used);
   }
 
@@ -129,26 +99,32 @@ struct IpcDirectionalChannel::MessageBuffer {
     void* buffer;
     size_t remaining_bytes;
 
-    Iterator(void* buffer, size_t remaining_bytes) : remaining_bytes(remaining_bytes) {}
+    Iterator(void* buffer, size_t remaining_bytes) : buffer(buffer), remaining_bytes(remaining_bytes) {}
 
     JsonMessage* get() const {
       assert(buffer);
       return reinterpret_cast<JsonMessage*>(buffer);
     }
 
+    JsonMessage* operator*() const {
+      return get();
+    }
+
     JsonMessage* operator->() const {
       return get();
     }
 
-    Iterator operator++() const {
+    void operator++() {
       size_t next_message_offset = sizeof(JsonMessage) + get()->payload_size;
       if (next_message_offset >= remaining_bytes) {
         assert(next_message_offset == remaining_bytes);
-        return Iterator(nullptr, 0);
+        buffer = nullptr;
+        remaining_bytes = 0;
+        return;
       }
 
-      auto* next_message = (char*)buffer + next_message_offset;
-      return Iterator(next_message, remaining_bytes - next_message_offset);
+      buffer = (char*)buffer + next_message_offset;
+      remaining_bytes -= next_message_offset;
     }
 
     bool operator==(const Iterator& other) const {
@@ -159,14 +135,71 @@ struct IpcDirectionalChannel::MessageBuffer {
     }
   };
 
-  Iterator begin() {
+  Iterator begin() const {
+    if (metadata()->bytes_used == 0)
+      return end();
+
     return Iterator(first_message(), metadata()->bytes_used);
   }
-  Iterator end() {
+  Iterator end() const {
     return Iterator(nullptr, 0);
   }
 };
 
+struct IpcDirectionalChannel::ResizableBuffer {
+  void* memory;
+  size_t size;
+  size_t capacity;
+
+  ResizableBuffer() {
+    memory = malloc(128);
+    size = 0;
+    capacity = 128;
+  }
+
+  ~ResizableBuffer() {
+    free(memory);
+    size = 0;
+    capacity = 0;
+  }
+
+  void Append(void* content, size_t content_size) {
+    assert(capacity);
+
+    // Grow memory if needed.
+    if ((size + content_size) >= capacity) {
+      size_t new_capacity = capacity * 2;
+      while (new_capacity < size + content_size)
+        new_capacity *= 2;
+      void* new_memory = malloc(new_capacity);
+      assert(size < capacity);
+      memcpy(new_memory, memory, size);
+      free(memory);
+      memory = new_memory;
+      capacity = new_capacity;
+    }
+
+    // Append new content into memory.
+    memcpy((char*)memory + size, content, content_size);
+    size += content_size;
+  }
+
+  void Reset() {
+    size = 0;
+  }
+};
+
+IpcDirectionalChannel::ResizableBuffer* IpcDirectionalChannel::CreateOrFindResizableBuffer(int id) {
+  auto it = resizable_buffers.find(id);
+  if (it != resizable_buffers.end())
+    return it->second.get();
+  return (resizable_buffers[id] = MakeUnique<ResizableBuffer>()).get();
+}
+
+void IpcDirectionalChannel::RemoveResizableBuffer(int id) {
+  resizable_buffers.erase(id);
+}
+
 IpcDirectionalChannel::IpcDirectionalChannel(const std::string& name) {
   shared = CreatePlatformSharedMemory(name + "memory");
   mutex = CreatePlatformMutex(name + "mutex");
@@ -180,16 +213,37 @@ IpcDirectionalChannel::IpcDirectionalChannel(const std::string& name) {
 
 IpcDirectionalChannel::~IpcDirectionalChannel() {}
 
-// TODO:
-//  We need to send partial payloads. But other payloads may appear in
-//  the middle of the payload.
-//
-//  
-//  int partial_payload_id = 0
-//  int num_uncompleted_payloads = 0
+enum class DispatchResult {
+  RunAgain,
+  Break
+};
+
+// Run |action| an arbitrary number of times.
+void IpcDispatch(PlatformMutex* mutex, std::function<DispatchResult()> action) {
+  bool first = true;
+  int log_iteration_count = 0;
+  int log_count = 0;
+  while (true) {
+    if (!first) {
+      if (log_iteration_count > 1000) {
+        log_iteration_count = 0;
+        std::cerr << "[info]: shmem full, waiting (" << log_count++ << ")" << std::endl; // TODO: remove
+      }
+      ++log_iteration_count;
+      std::this_thread::sleep_for(std::chrono::microseconds(0));
+    }
+    first = false;
+
+    std::unique_ptr<PlatformScopedMutexLock> lock = CreatePlatformScopedMutexLock(mutex);
+    if (action() == DispatchResult::RunAgain)
+      continue;
+    break;
+  }
+}
 
 void IpcDirectionalChannel::PushMessage(IpcMessage* message) {
   assert(message->ipc_id != IpcId::Invalid);
+  assert(shmem_size > sizeof(JsonMessage) + kMinimumPartialPayloadSize);
 
   rapidjson::StringBuffer output;
   rapidjson::PrettyWriter<rapidjson::StringBuffer> writer(output);
@@ -200,37 +254,61 @@ void IpcDirectionalChannel::PushMessage(IpcMessage* message) {
 
   //std::cerr << "Sending message with id " << message->runtime_id() << " (hash " << message->hashed_runtime_id() << ")" << std::endl;
 
-  size_t payload_size = strlen(output.GetString());
-  assert(payload_size < shmem_size && "Increase shared memory size, payload will never fit");
 
-  bool first = true;
-  bool did_log = false;
-  while (true) {
-    if (!first) {
-      if (!did_log) {
-        std::cerr << "[info]: shmem full, waiting" << std::endl; // TODO: remove
-        did_log = true;
-      }
-      std::this_thread::sleep_for(std::chrono::milliseconds(16));
+  size_t payload_size = output.GetSize();
+  const char* payload = output.GetString();
+  if (payload_size == 0)
+    return;
+
+  int partial_message_id = 0; // TODO
+
+  std::cerr << "Starting dispatch of payload with size " << payload_size << std::endl;
+
+  IpcDispatch(mutex.get(), [&]() {
+    assert(payload_size > 0);
+
+    // We cannot find the entire payload in the buffer. We
+    // have to send chunks of it over time.
+    if ((sizeof(JsonMessage) + payload_size) > shared_buffer->bytes_available()) {
+      if ((sizeof(JsonMessage) + kMinimumPartialPayloadSize) > shared_buffer->bytes_available())
+        return DispatchResult::RunAgain;
+
+      if (partial_message_id == 0)
+        partial_message_id = ++shared_buffer->metadata()->next_partial_message_id; // note: pre-increment so we 1 as initial value
+
+      size_t sent_payload_size = shared_buffer->bytes_available() - sizeof(JsonMessage);
+      shared_buffer->free_message()->Setup(message->ipc_id, partial_message_id, true /*has_more_chunks*/, sent_payload_size, payload);
+      shared_buffer->metadata()->bytes_used += sizeof(JsonMessage) + sent_payload_size;
+      shared_buffer->free_message()->ipc_id = IpcId::Invalid;
+      std::cerr << "Sending partial message with payload_size=" << sent_payload_size << std::endl;
+
+      // Prepare for next time.
+      payload_size -= sent_payload_size;
+      payload += sent_payload_size;
+      return DispatchResult::RunAgain;
     }
-    first = false;
+    // The entire payload fits. Send it all now.
+    else {
+      // Include partial message id, as there could have been previous parts of this payload.
+      shared_buffer->free_message()->Setup(message->ipc_id, partial_message_id, false /*has_more_chunks*/, payload_size, payload);
+      shared_buffer->metadata()->bytes_used += sizeof(JsonMessage) + payload_size;
+      shared_buffer->free_message()->ipc_id = IpcId::Invalid;
+      std::cerr << "Sending full message with payload_size=" << payload_size << std::endl;
 
-    std::unique_ptr<PlatformScopedMutexLock> lock = CreatePlatformScopedMutexLock(mutex.get());
+      return DispatchResult::Break;
+    }
+  });
+}
 
-    // Try again later when there is room in shared memory.
-    if ((shared_buffer->metadata()->bytes_used + sizeof(MessageBuffer::Metadata) + sizeof(JsonMessage) + payload_size) >= shmem_size)
-      continue;
-
-    shared_buffer->free_message()->ipc_id = message->ipc_id;
-    shared_buffer->free_message()->SetPayload(payload_size, output.GetString());
-
-    shared_buffer->metadata()->bytes_used += sizeof(JsonMessage) + shared_buffer->free_message()->payload_size;
-    assert((shared_buffer->metadata()->bytes_used + sizeof(MessageBuffer::Metadata)) < shmem_size);
-    assert(shared_buffer->metadata()->bytes_used >= 0);
-    shared_buffer->free_message()->ipc_id = IpcId::Invalid;
-    break;
-  }
+void AddIpcMessageFromJsonMessage(std::vector<std::unique_ptr<IpcMessage>>& result, IpcId ipc_id, void* payload, size_t payload_size) {
+  rapidjson::Document document;
+  document.Parse(reinterpret_cast<const char*>(payload), payload_size);
+  bool has_error = document.HasParseError();
+  auto error = document.GetParseError();
 
+  std::unique_ptr<IpcMessage> base_message = IpcRegistry::instance()->Allocate(ipc_id);
+  base_message->Deserialize(document);
+  result.emplace_back(std::move(base_message));
 }
 
 std::vector<std::unique_ptr<IpcMessage>> IpcDirectionalChannel::TakeMessages() {
@@ -250,31 +328,23 @@ std::vector<std::unique_ptr<IpcMessage>> IpcDirectionalChannel::TakeMessages() {
 
   std::vector<std::unique_ptr<IpcMessage>> result;
 
-  // TODO
-  for (auto it = local_buffer->begin(); it != local_buffer->end(); ++it) {
-    // TODO: partial payload, maybe something like this:
-    //
-    //  if (it->partial_id != 0) {
-    //    auto* buf = CreateOrFindResizableBuffer(it->partial_id);
-    //    buf->Append(it->payload(), it->payload_size());
-    //    if (it->is_complete) {
-    //      Process(buf.payload(), buff.payload_size())
-    //      RemoveResizableBuffer(it->partial_id)
-    //    }
-    //  }
-    //  else {
-    //    Process(it->payload(), it->payload_size())
-    //  }
-    //
-    rapidjson::Document document;
-    document.Parse(it->payload(), it->payload_size);
-    bool has_error = document.HasParseError();
-    auto error = document.GetParseError();
+  for (JsonMessage* message : *local_buffer) {
+    std::cerr << "Got message with payload_size=" << message->payload_size << std::endl;
 
-    std::unique_ptr<IpcMessage> base_message = IpcRegistry::instance()->Allocate(it->ipc_id);
-    base_message->Deserialize(document);
-    result.emplace_back(std::move(base_message));
+    if (message->partial_message_id != 0) {
+      auto* buf = CreateOrFindResizableBuffer(message->partial_message_id);
+      buf->Append(message->payload(), message->payload_size);
+      if (!message->has_more_chunks) {
+        AddIpcMessageFromJsonMessage(result, message->ipc_id, buf->memory, buf->size);
+        RemoveResizableBuffer(message->partial_message_id);
+      }
+    }
+    else {
+      assert(!message->has_more_chunks);
+      AddIpcMessageFromJsonMessage(result, message->ipc_id, message->payload(), message->payload_size);
+    }
   }
+  local_buffer->metadata()->bytes_used = 0;
 
   return result;
 }

ipc.h

@@ -93,7 +93,11 @@ struct IpcDirectionalChannel {
   std::vector<std::unique_ptr<IpcMessage>> TakeMessages();
 
   struct MessageBuffer;
+  struct ResizableBuffer;
 
+  ResizableBuffer* CreateOrFindResizableBuffer(int id);
+  void RemoveResizableBuffer(int id);
+  std::unordered_map<int, std::unique_ptr<ResizableBuffer>> resizable_buffers;
 
   // Pointer to process shared memory and process shared mutex.
   std::unique_ptr<PlatformSharedMemory> shared;

platform.h

@@ -14,7 +14,7 @@ struct PlatformSharedMemory {
   void* shared;
 };
 
-const int shmem_size = 50;// 1024 * 1024 * 32;  // number of chars/bytes (32mb)
+const int shmem_size = 200;// 1024 * 1024 * 32;  // number of chars/bytes (32mb)
 
 std::unique_ptr<PlatformMutex> CreatePlatformMutex(const std::string& name);
 std::unique_ptr<PlatformScopedMutexLock> CreatePlatformScopedMutexLock(PlatformMutex* mutex);