log, diff: Add --src-prefix, --dst-prefix, --no-prefix

Change-Id: I0c7154a51143d56362f12ee4fa93133778d3a9eb
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/CLIText.properties

 usage_displayAllPossibleMergeBases=display all possible merge bases
 usage_displayThejavaStackTraceOnExceptions=display the Java stack trace on exceptions
 usage_displayThisHelpText=display this help text
+usage_dstPrefix=show the destination prefix instead of "b/"
 usage_enableTheServiceInAllRepositories=enable the service in all repositories
 usage_exportRepositoriesOverGit=Export repositories over git://
 usage_exportWithoutGitDaemonExportOk=export without git-daemon-export-ok
 usage_logAllPretty=format:%H %ct %P' output=log --all '--pretty=format:%H %ct %P' output
 usage_moveRenameABranch=move/rename a branch
 usage_nameStatus=show only name and status of files
+usage_noPrefix=do not show any source or destination prefix
 usage_noRenames=disable rename detection
 usage_outputFile=Output file
 usage_path=path
 usage_setTheGitRepositoryToOperateOn=set the git repository to operate on
 usage_showRefNamesMatchingCommits=Show ref names matching commits
 usage_showPatch=display patch
+usage_srcPrefix=show the source prefix instead of "a/"
 usage_symbolicVersionForTheProject=Symbolic version for the project
 usage_synchronizeIPZillaData=Synchronize IPZilla data
 usage_tagMessage=tag message

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Diff.java

 		diffFmt.setAbbreviationLength(Constants.OBJECT_ID_STRING_LENGTH);
 	}
 
+	@Option(name = "--src-prefix", usage = "usage_srcPrefix")
+	void sourcePrefix(String path) {
+		diffFmt.setOldPrefix(path);
+	}
+
+	@Option(name = "--dst-prefix", usage = "usage_dstPrefix")
+	void dstPrefix(String path) {
+		diffFmt.setNewPrefix(path);
+	}
+
+	@Option(name = "--no-prefix", usage = "usage_noPrefix")
+	void noPrefix(@SuppressWarnings("unused") boolean on) {
+		diffFmt.setOldPrefix("");
+		diffFmt.setNewPrefix("");
+	}
+
 	// END -- Options shared with Log
 
 	@Override

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Log.java

 		diffFmt.setAbbreviationLength(Constants.OBJECT_ID_STRING_LENGTH);
 	}
 
+	@Option(name = "--src-prefix", usage = "usage_srcPrefix")
+	void sourcePrefix(String path) {
+		diffFmt.setOldPrefix(path);
+	}
+
+	@Option(name = "--dst-prefix", usage = "usage_dstPrefix")
+	void dstPrefix(String path) {
+		diffFmt.setNewPrefix(path);
+	}
+
+	@Option(name = "--no-prefix", usage = "usage_noPrefix")
+	void noPrefix(@SuppressWarnings("unused") boolean on) {
+		diffFmt.setOldPrefix("");
+		diffFmt.setNewPrefix("");
+	}
+
 	// END -- Options shared with Diff
 
 	Log() {