Core/Common: Add a generic config helper to access built-in overwriteable paths.

* Adds CMAKE_COMMAND and CMAKE_BINARY_DIR to revision_data.h
* Move the source and mysql exe path handling out of the DBUpdater.
* Make some Config methods const for correctness.
* Remove C & CXX flags from revision_data.h
 (was unused and didn't capture all cxx vars)
* Reorder the link order to prevent `ld` from ignoring the file
* Ref #15671

4 files changed, 102 insertions, 8 deletions

diff --git a/src/common/Configuration/BuiltInConfig.cpp b/src/common/Configuration/BuiltInConfig.cpp
new file mode 100644
index 00000000000..c2fc3b91766
--- /dev/null
+++ b/src/common/Configuration/BuiltInConfig.cpp
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2008-2016 TrinityCore <http://www.trinitycore.org/>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "BuiltInConfig.h"
+#include "Config.h"
+#include "GitRevision.h"
+
+template<typename Fn>
+static std::string GetStringWithDefaultValueFromFunction(
+    std::string const& key, Fn getter)
+{
+    std::string const value = sConfigMgr->GetStringDefault(key, "");
+    return value.empty() ? getter() : value;
+}
+
+std::string BuiltInConfig::GetCMakeCommand()
+{
+    return GetStringWithDefaultValueFromFunction(
+        "CMakeCommand", GitRevision::GetCMakeCommand);
+}
+
+std::string BuiltInConfig::GetBuildDirectory()
+{
+    return GetStringWithDefaultValueFromFunction(
+        "BuildDirectory", GitRevision::GetBuildDirectory);
+}
+
+std::string BuiltInConfig::GetSourceDirectory()
+{
+    return GetStringWithDefaultValueFromFunction(
+        "SourceDirectory", GitRevision::GetSourceDirectory);
+}
+
+std::string BuiltInConfig::GetMySQLExecutable()
+{
+    return GetStringWithDefaultValueFromFunction(
+        "MySQLExecutable", GitRevision::GetMySQLExecutable);
+}
diff --git a/src/common/Configuration/BuiltInConfig.h b/src/common/Configuration/BuiltInConfig.h
new file mode 100644
index 00000000000..4ae4ed40189
--- /dev/null
+++ b/src/common/Configuration/BuiltInConfig.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2008-2016 TrinityCore <http://www.trinitycore.org/>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef BUILT_IN_CONFIG_H
+#define BUILT_IN_CONFIG_H
+
+#include <string>
+
+/// Provides helper functions to access built-in values
+/// which can be overwritten in config
+namespace BuiltInConfig
+{
+    /// Returns the CMake command when any is specified in the config,
+    /// returns the built-in path otherwise
+    std::string GetCMakeCommand();
+    /// Returns the build directory path when any is specified in the config,
+    /// returns the built-in one otherwise
+    std::string GetBuildDirectory();
+    /// Returns the source directory path when any is specified in the config,
+    /// returns the built-in one otherwise
+    std::string GetSourceDirectory();
+    /// Returns the path to the mysql executable (`mysql`) when any is specified
+    /// in the config, returns the built-in one otherwise
+    std::string GetMySQLExecutable();
+
+} // namespace BuiltInConfig
+
+#endif // BUILT_IN_CONFIG_H
diff --git a/src/common/Configuration/Config.cpp b/src/common/Configuration/Config.cpp
index b0f2e027ad4..196c128532e 100644
--- a/src/common/Configuration/Config.cpp
+++ b/src/common/Configuration/Config.cpp
@@ -62,7 +62,7 @@ bool ConfigMgr::Reload(std::string& error)
     return LoadInitial(_filename, error);
 }
 
-std::string ConfigMgr::GetStringDefault(std::string const& name, const std::string& def)
+std::string ConfigMgr::GetStringDefault(std::string const& name, const std::string& def) const
 {
     std::string value = _config.get<std::string>(ptree::path_type(name, '/'), def);
 
@@ -71,7 +71,7 @@ std::string ConfigMgr::GetStringDefault(std::string const& name, const std::stri
     return value;
 }
 
-bool ConfigMgr::GetBoolDefault(std::string const& name, bool def)
+bool ConfigMgr::GetBoolDefault(std::string const& name, bool def) const
 {
     try
     {
@@ -85,12 +85,12 @@ bool ConfigMgr::GetBoolDefault(std::string const& name, bool def)
     }
 }
 
-int ConfigMgr::GetIntDefault(std::string const& name, int def)
+int ConfigMgr::GetIntDefault(std::string const& name, int def) const
 {
     return _config.get<int>(ptree::path_type(name, '/'), def);
 }
 
-float ConfigMgr::GetFloatDefault(std::string const& name, float def)
+float ConfigMgr::GetFloatDefault(std::string const& name, float def) const
 {
     return _config.get<float>(ptree::path_type(name, '/'), def);
 }
diff --git a/src/common/Configuration/Config.h b/src/common/Configuration/Config.h
index 0becaed96ba..77150e9b436 100644
--- a/src/common/Configuration/Config.h
+++ b/src/common/Configuration/Config.h
@@ -41,10 +41,10 @@ public:
 
     bool Reload(std::string& error);
 
-    std::string GetStringDefault(std::string const& name, const std::string& def);
-    bool GetBoolDefault(std::string const& name, bool def);
-    int GetIntDefault(std::string const& name, int def);
-    float GetFloatDefault(std::string const& name, float def);
+    std::string GetStringDefault(std::string const& name, const std::string& def) const;
+    bool GetBoolDefault(std::string const& name, bool def) const;
+    int GetIntDefault(std::string const& name, int def) const;
+    float GetFloatDefault(std::string const& name, float def) const;
 
     std::string const& GetFilename();
     std::list<std::string> GetKeysByString(std::string const& name);