cmake-server: Bare-bones server implementation

Adds a bare-bones cmake-server implementation and makes it possible
to start that with "cmake -E server".

Communication happens via stdin/stdout for now.

Protocol is based on Json objects surrounded by magic strings
("[== CMake Server ==[" and "]== CMake Server ==]"), which simplifies
Json parsing significantly.

This patch also defines an interface used to implement different
versions of the protocol spoken by the server, but does not include
any protocol implementaiton.

1 files changed, 352 insertions, 0 deletions

diff --git a/Source/cmServer.cxx b/Source/cmServer.cxx
new file mode 100644
index 0000000..7643b47
--- /dev/null
+++ b/Source/cmServer.cxx
@@ -0,0 +1,352 @@
+/*============================================================================
+  CMake - Cross Platform Makefile Generator
+  Copyright 2015 Stephen Kelly <steveire@gmail.com>
+  Copyright 2016 Tobias Hunger <tobias.hunger@qt.io>
+
+  Distributed under the OSI-approved BSD License (the "License");
+  see accompanying file Copyright.txt for details.
+
+  This software is distributed WITHOUT ANY WARRANTY; without even the
+  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+  See the License for more information.
+============================================================================*/
+
+#include "cmServer.h"
+
+#include "cmServerProtocol.h"
+#include "cmVersionMacros.h"
+#include "cmake.h"
+
+#if defined(CMAKE_BUILD_WITH_CMAKE)
+#include "cm_jsoncpp_reader.h"
+#include "cm_jsoncpp_value.h"
+#endif
+
+const char kTYPE_KEY[] = "type";
+const char kCOOKIE_KEY[] = "cookie";
+const char REPLY_TO_KEY[] = "inReplyTo";
+const char ERROR_MESSAGE_KEY[] = "errorMessage";
+
+const char ERROR_TYPE[] = "error";
+const char REPLY_TYPE[] = "reply";
+const char PROGRESS_TYPE[] = "progress";
+
+const char START_MAGIC[] = "[== CMake Server ==[";
+const char END_MAGIC[] = "]== CMake Server ==]";
+
+typedef struct
+{
+  uv_write_t req;
+  uv_buf_t buf;
+} write_req_t;
+
+void alloc_buffer(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf)
+{
+  (void)handle;
+  *buf = uv_buf_init(static_cast<char*>(malloc(suggested_size)),
+                     static_cast<unsigned int>(suggested_size));
+}
+
+void free_write_req(uv_write_t* req)
+{
+  write_req_t* wr = reinterpret_cast<write_req_t*>(req);
+  free(wr->buf.base);
+  free(wr);
+}
+
+void on_stdout_write(uv_write_t* req, int status)
+{
+  (void)status;
+  auto server = reinterpret_cast<cmServer*>(req->data);
+  free_write_req(req);
+  server->PopOne();
+}
+
+void write_data(uv_stream_t* dest, std::string content, uv_write_cb cb)
+{
+  write_req_t* req = static_cast<write_req_t*>(malloc(sizeof(write_req_t)));
+  req->req.data = dest->data;
+  req->buf = uv_buf_init(static_cast<char*>(malloc(content.size())),
+                         static_cast<unsigned int>(content.size()));
+  memcpy(req->buf.base, content.c_str(), content.size());
+  uv_write(reinterpret_cast<uv_write_t*>(req), static_cast<uv_stream_t*>(dest),
+           &req->buf, 1, cb);
+}
+
+void read_stdin(uv_stream_t* stream, ssize_t nread, const uv_buf_t* buf)
+{
+  if (nread > 0) {
+    auto server = reinterpret_cast<cmServer*>(stream->data);
+    std::string result = std::string(buf->base, buf->base + nread);
+    server->handleData(result);
+  }
+
+  if (buf->base)
+    free(buf->base);
+}
+
+cmServer::cmServer()
+{
+}
+
+cmServer::~cmServer()
+{
+  if (!this->Protocol) // Daemon was never fully started!
+    return;
+
+  uv_close(reinterpret_cast<uv_handle_t*>(this->InputStream), NULL);
+  uv_close(reinterpret_cast<uv_handle_t*>(this->OutputStream), NULL);
+  uv_loop_close(this->Loop);
+
+  for (cmServerProtocol* p : this->SupportedProtocols) {
+    delete p;
+  }
+}
+
+void cmServer::PopOne()
+{
+  this->Writing = false;
+  if (this->Queue.empty()) {
+    return;
+  }
+
+  Json::Reader reader;
+  Json::Value value;
+  const std::string input = this->Queue.front();
+  this->Queue.erase(this->Queue.begin());
+
+  if (!reader.parse(input, value)) {
+    this->WriteParseError("Failed to parse JSON input.");
+    return;
+  }
+
+  const cmServerRequest request(this, value[kTYPE_KEY].asString(),
+                                value[kCOOKIE_KEY].asString(), value);
+
+  if (request.Type == "") {
+    cmServerResponse response(request);
+    response.SetError("No type given in request.");
+    this->WriteResponse(response);
+    return;
+  }
+
+  this->WriteResponse(this->Protocol ? this->Protocol->Process(request)
+                                     : this->SetProtocolVersion(request));
+}
+
+void cmServer::handleData(const std::string& data)
+{
+  this->DataBuffer += data;
+
+  for (;;) {
+    auto needle = this->DataBuffer.find('\n');
+
+    if (needle == std::string::npos) {
+      return;
+    }
+    std::string line = this->DataBuffer.substr(0, needle);
+    const auto ls = line.size();
+    if (ls > 1 && line.at(ls - 1) == '\r')
+      line.erase(ls - 1, 1);
+    this->DataBuffer.erase(this->DataBuffer.begin(),
+                           this->DataBuffer.begin() + needle + 1);
+    if (line == START_MAGIC) {
+      this->JsonData.clear();
+      continue;
+    }
+    if (line == END_MAGIC) {
+      this->Queue.push_back(this->JsonData);
+      this->JsonData.clear();
+      if (!this->Writing) {
+        this->PopOne();
+      }
+    } else {
+      this->JsonData += line;
+      this->JsonData += "\n";
+    }
+  }
+}
+
+void cmServer::RegisterProtocol(cmServerProtocol* protocol)
+{
+  auto version = protocol->ProtocolVersion();
+  assert(version.first >= 0);
+  assert(version.second >= 0);
+  auto it = std::find_if(this->SupportedProtocols.begin(),
+                         this->SupportedProtocols.end(),
+                         [version](cmServerProtocol* p) {
+                           return p->ProtocolVersion() == version;
+                         });
+  if (it == this->SupportedProtocols.end())
+    this->SupportedProtocols.push_back(protocol);
+}
+
+void cmServer::PrintHello() const
+{
+  Json::Value hello = Json::objectValue;
+  hello[kTYPE_KEY] = "hello";
+
+  Json::Value& protocolVersions = hello["supportedProtocolVersions"] =
+    Json::arrayValue;
+
+  for (auto const& proto : this->SupportedProtocols) {
+    auto version = proto->ProtocolVersion();
+    Json::Value tmp = Json::objectValue;
+    tmp["major"] = version.first;
+    tmp["minor"] = version.second;
+    protocolVersions.append(tmp);
+  }
+
+  this->WriteJsonObject(hello);
+}
+
+cmServerResponse cmServer::SetProtocolVersion(const cmServerRequest& request)
+{
+  if (request.Type != "handshake")
+    return request.ReportError("Waiting for type \"handshake\".");
+
+  Json::Value requestedProtocolVersion = request.Data["protocolVersion"];
+  if (requestedProtocolVersion.isNull())
+    return request.ReportError(
+      "\"protocolVersion\" is required for \"handshake\".");
+
+  if (!requestedProtocolVersion.isObject())
+    return request.ReportError("\"protocolVersion\" must be a JSON object.");
+
+  Json::Value majorValue = requestedProtocolVersion["major"];
+  if (!majorValue.isInt())
+    return request.ReportError("\"major\" must be set and an integer.");
+
+  Json::Value minorValue = requestedProtocolVersion["minor"];
+  if (!minorValue.isNull() && !minorValue.isInt())
+    return request.ReportError("\"minor\" must be unset or an integer.");
+
+  const int major = majorValue.asInt();
+  const int minor = minorValue.isNull() ? -1 : minorValue.asInt();
+  if (major < 0)
+    return request.ReportError("\"major\" must be >= 0.");
+  if (!minorValue.isNull() && minor < 0)
+    return request.ReportError("\"minor\" must be >= 0 when set.");
+
+  this->Protocol =
+    this->FindMatchingProtocol(this->SupportedProtocols, major, minor);
+  if (!this->Protocol) {
+    return request.ReportError("Protocol version not supported.");
+  }
+
+  std::string errorMessage;
+  if (!this->Protocol->Activate(request, &errorMessage)) {
+    this->Protocol = CM_NULLPTR;
+    return request.ReportError("Failed to activate protocol version: " +
+                               errorMessage);
+  }
+  return request.Reply(Json::objectValue);
+}
+
+void cmServer::Serve()
+{
+  assert(!this->Protocol);
+
+  this->Loop = uv_default_loop();
+
+  if (uv_guess_handle(1) == UV_TTY) {
+    uv_tty_init(this->Loop, &this->Input.tty, 0, 1);
+    uv_tty_set_mode(&this->Input.tty, UV_TTY_MODE_NORMAL);
+    this->Input.tty.data = this;
+    InputStream = reinterpret_cast<uv_stream_t*>(&this->Input.tty);
+
+    uv_tty_init(this->Loop, &this->Output.tty, 1, 0);
+    uv_tty_set_mode(&this->Output.tty, UV_TTY_MODE_NORMAL);
+    this->Output.tty.data = this;
+    OutputStream = reinterpret_cast<uv_stream_t*>(&this->Output.tty);
+  } else {
+    uv_pipe_init(this->Loop, &this->Input.pipe, 0);
+    uv_pipe_open(&this->Input.pipe, 0);
+    this->Input.pipe.data = this;
+    InputStream = reinterpret_cast<uv_stream_t*>(&this->Input.pipe);
+
+    uv_pipe_init(this->Loop, &this->Output.pipe, 0);
+    uv_pipe_open(&this->Output.pipe, 1);
+    this->Output.pipe.data = this;
+    OutputStream = reinterpret_cast<uv_stream_t*>(&this->Output.pipe);
+  }
+
+  this->PrintHello();
+
+  uv_read_start(this->InputStream, alloc_buffer, read_stdin);
+
+  uv_run(this->Loop, UV_RUN_DEFAULT);
+}
+
+void cmServer::WriteJsonObject(const Json::Value& jsonValue) const
+{
+  Json::FastWriter writer;
+
+  std::string result = std::string("\n") + std::string(START_MAGIC) +
+    std::string("\n") + writer.write(jsonValue) + std::string(END_MAGIC) +
+    std::string("\n");
+
+  this->Writing = true;
+  write_data(this->OutputStream, result, on_stdout_write);
+}
+
+cmServerProtocol* cmServer::FindMatchingProtocol(
+  const std::vector<cmServerProtocol*>& protocols, int major, int minor)
+{
+  cmServerProtocol* bestMatch = nullptr;
+  for (auto protocol : protocols) {
+    auto version = protocol->ProtocolVersion();
+    if (major != version.first)
+      continue;
+    if (minor == version.second)
+      return protocol;
+    if (!bestMatch || bestMatch->ProtocolVersion().second < version.second)
+      bestMatch = protocol;
+  }
+  return minor < 0 ? bestMatch : nullptr;
+}
+
+void cmServer::WriteProgress(const cmServerRequest& request, int min,
+                             int current, int max,
+                             const std::string& message) const
+{
+  assert(min <= current && current <= max);
+  assert(message.length() != 0);
+
+  Json::Value obj = Json::objectValue;
+  obj[kTYPE_KEY] = PROGRESS_TYPE;
+  obj[REPLY_TO_KEY] = request.Type;
+  obj[kCOOKIE_KEY] = request.Cookie;
+  obj["progressMessage"] = message;
+  obj["progressMinimum"] = min;
+  obj["progressMaximum"] = max;
+  obj["progressCurrent"] = current;
+
+  this->WriteJsonObject(obj);
+}
+
+void cmServer::WriteParseError(const std::string& message) const
+{
+  Json::Value obj = Json::objectValue;
+  obj[kTYPE_KEY] = ERROR_TYPE;
+  obj[ERROR_MESSAGE_KEY] = message;
+  obj[REPLY_TO_KEY] = "";
+  obj[kCOOKIE_KEY] = "";
+
+  this->WriteJsonObject(obj);
+}
+
+void cmServer::WriteResponse(const cmServerResponse& response) const
+{
+  assert(response.IsComplete());
+
+  Json::Value obj = response.Data();
+  obj[kCOOKIE_KEY] = response.Cookie;
+  obj[kTYPE_KEY] = response.IsError() ? ERROR_TYPE : REPLY_TYPE;
+  obj[REPLY_TO_KEY] = response.Type;
+  if (response.IsError()) {
+    obj[ERROR_MESSAGE_KEY] = response.ErrorMessage();
+  }
+
+  this->WriteJsonObject(obj);
+}