[GEODE-42] Remove hardcoded versioning from GemFireVersion.properties…

… file

The version information was hardcoded in the initial drop of the Geode code base. This change allows the build to get source revision information from Git, if available. If source information is not available, then value  is 'UNKNOWN'.

Tested with and without Git workspace.

Reviewed by: amb

gemfire-core/build.gradle

@@ -64,10 +64,46 @@ dependencies {
 
 // Creates the version properties file and writes it to the classes dir
 task createVersionPropertiesFile << {
-  ext.gitBranch = 'master'
-  ext.commitId = '1366ff2d4fcbf54bfad684e9ba9822db2a2b0ff5'
-  ext.sourceDate = '2015-04-06 14:54:51 -0700'
-
+
+  def gitFolder = new File ("${rootProject.projectDir}/.git")
+  if ( gitFolder.exists() ) {
+    new ByteArrayOutputStream().withStream { gitBranchStream ->
+      def result = exec {
+        standardOutput = gitBranchStream
+        executable = "git"
+        args = ['rev-parse', '--abbrev-ref', 'HEAD']
+      }
+      ext.gitBranchString = gitBranchStream.toString()
+      ext.gitBranch = ext.gitBranchString.trim()
+    }
+
+    new ByteArrayOutputStream().withStream { commitStream ->
+      def result = exec {
+        standardOutput = commitStream
+        executable = "git"
+        args = ['rev-parse', 'HEAD']
+      }
+      ext.commitIdString = commitStream.toString()
+      ext.commitId = ext.commitIdString.trim()
+    }
+
+    new ByteArrayOutputStream().withStream { sourceDateStream ->
+      def result = exec {
+        standardOutput = sourceDateStream
+        executable = "git"
+        args = ['show', '-s', '--format=%ci', "${ext.commitId}"]
+      }
+      ext.sourceDateString = sourceDateStream.toString()
+      ext.sourceDate = ext.sourceDateString.trim()
+    }
+  }
+  else {
+    // Not in SCM workspace, use default values
+    ext.gitBranch = 'UNKNOWN'
+    ext.commitId = 'UNKNOWN'
+    ext.sourceDate = new Date().format('yyyy-MM-dd HH:mm:ss Z')
+  }
+
   ext.osArch = System.getProperty('os.arch')
   ext.osName = System.getProperty('os.name')
   ext.osVersion = System.getProperty('os.version')