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, 97 insertions, 0 deletions

diff --git a/Source/cmServerProtocol.h b/Source/cmServerProtocol.h
new file mode 100644
index 0000000..e086f72
--- /dev/null
+++ b/Source/cmServerProtocol.h
@@ -0,0 +1,97 @@
+/*============================================================================
+  CMake - Cross Platform Makefile Generator
+  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.
+============================================================================*/
+
+#pragma once
+
+#include "cmListFileCache.h"
+
+#if defined(CMAKE_BUILD_WITH_CMAKE)
+#include "cm_jsoncpp_writer.h"
+#endif
+
+#include <memory>
+#include <string>
+
+class cmake;
+class cmServer;
+
+class cmServerRequest;
+
+class cmServerResponse
+{
+public:
+  explicit cmServerResponse(const cmServerRequest& request);
+
+  void SetData(const Json::Value& data);
+  void SetError(const std::string& message);
+
+  bool IsComplete() const;
+  bool IsError() const;
+  std::string ErrorMessage() const;
+  Json::Value Data() const;
+
+  const std::string Type;
+  const std::string Cookie;
+
+private:
+  enum PayLoad
+  {
+    PAYLOAD_UNKNOWN,
+    PAYLOAD_ERROR,
+    PAYLOAD_DATA
+  };
+  PayLoad m_Payload = PAYLOAD_UNKNOWN;
+  std::string m_ErrorMessage;
+  Json::Value m_Data;
+};
+
+class cmServerRequest
+{
+public:
+  void ReportProgress(int min, int current, int max,
+                      const std::string& message) const;
+
+  cmServerResponse Reply(const Json::Value& data) const;
+  cmServerResponse ReportError(const std::string& message) const;
+
+  const std::string Type;
+  const std::string Cookie;
+  const Json::Value Data;
+
+private:
+  cmServerRequest(cmServer* server, const std::string& t, const std::string& c,
+                  const Json::Value& d);
+
+  cmServer* m_Server;
+
+  friend class cmServer;
+};
+
+class cmServerProtocol
+{
+public:
+  virtual ~cmServerProtocol() {}
+
+  virtual std::pair<int, int> ProtocolVersion() const = 0;
+  virtual const cmServerResponse Process(const cmServerRequest& request) = 0;
+
+  bool Activate(const cmServerRequest& request, std::string* errorMessage);
+
+protected:
+  cmake* CMakeInstance() const;
+  // Implement protocol specific activation tasks here. Called from Activate().
+  virtual bool DoActivate(const cmServerRequest& request,
+                          std::string* errorMessage);
+
+private:
+  std::unique_ptr<cmake> m_CMakeInstance;
+};