/*
 *	aegis - project change supervisor
 *	Copyright (C) 2001 Peter Miller;
 *	All rights reserved.
 *
 *	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, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 * MANIFEST: functions to manipulate run_patchs
 */

#include <change.h>
#include <change/env_set.h>
#include <error.h> /* for assert */
#include <os.h>
#include <project.h>
#include <sub.h>
#include <trace.h>
#include <user.h>


void
change_run_patch_diff_command(cp, up, original, input, output, index_name)
	change_ty	*cp;
	user_ty		*up;
	string_ty	*original;
	string_ty	*input;
	string_ty	*output;
	string_ty	*index_name;
{
	sub_context_ty	*scp;
	pconf		pconf_data;
	string_ty	*dd;
	string_ty	*the_command;

	/*
	 * The difference of 2 files, to send around as a patch.
	 * (This isn't the same as diff_command, because it's aimed at
	 * GNU Patch, not at humans.)
         *
	 * All of the substitutions described in aesub(5) are available.
	 * In addition
	 *
	 * ${Original}
	 *	absolute path of original file copied from the baseline
	 *	usually, but not always
	 *
	 * ${Input}
	 *	absolute path of current file in the development directory
	 *	usually, but not always
	 *
	 * ${Output}
	 *	absolute path of file in which to write the
	 *	patch difference listing usually in the development
	 *	diretcory
	 *
	 * ${INDex}
	 *	The project-relative path of file being differenced.
	 *	This is the name to be used to index the file within the
	 *	patch, to ensure that patch(1) applies the patch to the
	 *	correct file.  (You don't want it applying the patch to
	 *	any of the absolute paths mentioned above, especially
	 *	as they could well be temporary files created for the
	 *	purpose of generating the patch.)
	 */
	trace
	((
		"change_run_patch_diff_command(cp = %8.8lX, up = %8.8lX, \
original = \"%s\", input = \"%s\", output = \"%s\")\n{\n"/*}*/,
		(long)cp,
		(long)up,
		original->str_text,
		input->str_text,
		output->str_text
	));
	assert(cp->reference_count >= 1);
	pconf_data = change_pconf_get(cp, 1);
	switch (change_cstate_get(cp)->state)
	{
	case cstate_state_being_developed:
		dd = change_development_directory_get(cp, 0);
		break;

	case cstate_state_completed:
		dd = project_baseline_path_get(cp->pp, 0);
		break;

	default:
		dd = change_integration_directory_get(cp, 0);
		break;
	}
	assert(dd);
	scp = sub_context_new();
	sub_var_set_string(scp, "ORiginal", original);
	sub_var_set_string(scp, "Input", input);
	sub_var_set_string(scp, "Output", output);
	sub_var_set_string(scp, "INDex", index_name);
	sub_var_optional(scp, "INDex");
	the_command = pconf_data->patch_diff_command;
	if (!the_command)
	{
		/*
		 * This one defaults, without user attention.
		 * It's aimed at GNU Patch, not at a human.
		 */
		the_command =
			str_from_c
			(
"set +e; \
diff -c -L ${quote $index} -L ${quote $index} \
${quote $original} ${quote $input} > ${quote $output}; \
test $? -le 1"
			);
	}
	the_command = substitute(scp, cp, the_command);
	sub_context_delete(scp);
	trace_string(the_command->str_text);
	change_env_set(cp, 0);
	user_become(up);
	if (os_exists(output))
		os_unlink(output);
	os_execute(the_command, OS_EXEC_FLAG_NO_INPUT, dd);
	user_become_undo();
	str_free(the_command);
	trace((/*{*/"}\n"));
}