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, 129 insertions, 0 deletions

diff --git a/Source/cmServerProtocol.cxx b/Source/cmServerProtocol.cxx
new file mode 100644
index 0000000..659aa0f
--- /dev/null
+++ b/Source/cmServerProtocol.cxx
@@ -0,0 +1,129 @@
+/*============================================================================
+  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.
+============================================================================*/
+
+#include "cmServerProtocol.h"
+
+#include "cmExternalMakefileProjectGenerator.h"
+#include "cmServer.h"
+#include "cmake.h"
+
+#if defined(CMAKE_BUILD_WITH_CMAKE)
+#include "cm_jsoncpp_reader.h"
+#include "cm_jsoncpp_value.h"
+#endif
+
+namespace {
+// Vocabulary:
+
+const std::string kCOOKIE_KEY = "cookie";
+const std::string kTYPE_KEY = "type";
+
+} // namespace
+
+cmServerRequest::cmServerRequest(cmServer* server, const std::string& t,
+                                 const std::string& c, const Json::Value& d)
+  : Type(t)
+  , Cookie(c)
+  , Data(d)
+  , m_Server(server)
+{
+}
+
+void cmServerRequest::ReportProgress(int min, int current, int max,
+                                     const std::string& message) const
+{
+  this->m_Server->WriteProgress(*this, min, current, max, message);
+}
+
+cmServerResponse cmServerRequest::Reply(const Json::Value& data) const
+{
+  cmServerResponse response(*this);
+  response.SetData(data);
+  return response;
+}
+
+cmServerResponse cmServerRequest::ReportError(const std::string& message) const
+{
+  cmServerResponse response(*this);
+  response.SetError(message);
+  return response;
+}
+
+cmServerResponse::cmServerResponse(const cmServerRequest& request)
+  : Type(request.Type)
+  , Cookie(request.Cookie)
+{
+}
+
+void cmServerResponse::SetData(const Json::Value& data)
+{
+  assert(this->m_Payload == PAYLOAD_UNKNOWN);
+  if (!data[kCOOKIE_KEY].isNull() || !data[kTYPE_KEY].isNull()) {
+    this->SetError("Response contains cookie or type field.");
+    return;
+  }
+  this->m_Payload = PAYLOAD_DATA;
+  this->m_Data = data;
+}
+
+void cmServerResponse::SetError(const std::string& message)
+{
+  assert(this->m_Payload == PAYLOAD_UNKNOWN);
+  this->m_Payload = PAYLOAD_ERROR;
+  this->m_ErrorMessage = message;
+}
+
+bool cmServerResponse::IsComplete() const
+{
+  return this->m_Payload != PAYLOAD_UNKNOWN;
+}
+
+bool cmServerResponse::IsError() const
+{
+  assert(this->m_Payload != PAYLOAD_UNKNOWN);
+  return this->m_Payload == PAYLOAD_ERROR;
+}
+
+std::string cmServerResponse::ErrorMessage() const
+{
+  if (this->m_Payload == PAYLOAD_ERROR)
+    return this->m_ErrorMessage;
+  else
+    return std::string();
+}
+
+Json::Value cmServerResponse::Data() const
+{
+  assert(this->m_Payload != PAYLOAD_UNKNOWN);
+  return this->m_Data;
+}
+
+bool cmServerProtocol::Activate(const cmServerRequest& request,
+                                std::string* errorMessage)
+{
+  this->m_CMakeInstance = std::make_unique<cmake>();
+  const bool result = this->DoActivate(request, errorMessage);
+  if (!result)
+    this->m_CMakeInstance = CM_NULLPTR;
+  return result;
+}
+
+cmake* cmServerProtocol::CMakeInstance() const
+{
+  return this->m_CMakeInstance.get();
+}
+
+bool cmServerProtocol::DoActivate(const cmServerRequest& /*request*/,
+                                  std::string* /*errorMessage*/)
+{
+  return true;
+}