swish/commit

Added new upstream file patch.pl

diff --git a/Makefile b/Makefile
index c92dfe3..3ee5f96 100644
--- a/Makefile
+++ b/Makefile
@@ -9,7 +9,8 @@ SWISHLIB=storage.pl page.pl help.pl examples.pl config.pl gitty.pl \
 	 highlight.pl render.pl template_hint.pl search.pl form.pl \
 	 include.pl swish_csv.pl logging.pl trace.pl markdown.pl \
 	 gitty_driver_files.pl gitty_driver_bdb.pl gitty_tools.pl \
-	 swish_debug.pl profiles.pl procps.pl download.pl r_swish.pl
+	 swish_debug.pl profiles.pl procps.pl download.pl r_swish.pl \
+	 patch.pl
 RENDER=table.pl graphviz.pl c3.pl
 LIBS=	$(addprefix lib/swish/, $(SWISHLIB)) \
 	$(addprefix lib/swish/render/, $(RENDER))
diff --git a/lib/swish/patch.pl b/lib/swish/patch.pl
new file mode 100644
index 0000000..c0ac9f0
--- /dev/null
+++ b/lib/swish/patch.pl
@@ -0,0 +1,118 @@
+/*  Part of SWISH
+
+    Author:        Jan Wielemaker
+    E-mail:        J.Wielemaker@cs.vu.nl
+    WWW:           http://www.swi-prolog.org
+    Copyright (C): 2014-2016, VU University Amsterdam
+			      CWI Amsterdam
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in
+       the documentation and/or other materials provided with the
+       distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+    POSSIBILITY OF SUCH DAMAGE.
+*/
+
+:- module(patch,
+	  [ patch/4				% +Data, +Diff, -Merged, +Options
+	  ]).
+:- use_module(library(process)).
+:- use_module(library(option)).
+
+/** <module> Run patch program
+
+This library uses the GNU patch(1) program to merge changes.
+*/
+
+:- predicate_options(patch/4, 4,
+		     [ status(-compound),
+		       stderr(-string)
+		     ]).
+
+%%	patch(+Orig:string, +Diff:string, -Merged:string, +Options)
+%
+%	Patch the string Orig using Diff.  Options:
+%
+%	  - status(-Status)
+%	  Unify Status with the completion status of patch.  This
+%	  is exit(0) for smooth completion and exit(1) if there are
+%	  merge conflicts.
+%	  - stderr(-String)
+%	  Unify String with the data patch(1) sent to standard error.
+
+patch(Orig, Diff, Merged, Options) :-
+	setup_call_cleanup(
+	    tmp_file_stream(utf8, TmpFile, Out),
+	    (	call_cleanup(format(Out, '~s', [Orig]),
+			     close(Out)),
+		run_patch(TmpFile, Diff, Merged, Options)
+	    ),
+	    delete_file(TmpFile)).
+
+run_patch(File, Diff, Merged, Options) :-
+	thread_self(Me),
+	setup_call_cleanup(
+	    process_create(path(patch),
+			   [ '--force', '--merge', '--silent',
+			     '--output=-', file(File) ],
+			   [ stdin(pipe(In)),
+			     stdout(pipe(Out)),
+			     stderr(pipe(Err)),
+			     process(PID)
+			   ]),
+	    ( set_stream(In, encoding(utf8)),
+	      set_stream(Out, encoding(utf8)),
+	      set_stream(Err, encoding(utf8)),
+	      thread_create(copy_diff(Diff, In), _, [detached(true)]),
+	      thread_create(read_stderr(Me, Err), ErrThread, []),
+	      read_string(Out, _, Merged)
+	    ),
+	    ( close(Out),
+	      process_wait(PID, Status)
+	    )),
+	get_errors(ErrThread, Options),
+	(   option(status(VarStat), Options)
+	->  VarStat = Status
+	;   true
+	).
+
+copy_diff(Diff, To) :-
+	call_cleanup(
+	    format(To, '~s', [Diff]),
+	    close(To)).
+
+read_stderr(Master, Stderr) :-
+	read_string(Stderr, _, Errors),
+	thread_send_message(Master, patch_errors(Errors)).
+
+get_errors(Thread, Options) :-
+	thread_join(Thread, Status),
+	(   Status == true
+	->  thread_get_message(patch_errors(Errors))
+	;   Status == exception(Error)
+	->  throw(Error)
+	),
+	(   option(stderr(Var), Options)
+	->  Var = Errors
+	;   true
+	).