toys/patch.c - third_party/toybox - Git at Google

 /* vi: set sw=4 ts=4:
  *
  * patch.c - Apply a "universal" diff.
  *
  * Copyright 2007 Rob Landley <rob@landley.net>
  *
  * see http://www.opengroup.org/onlinepubs/009695399/utilities/patch.html
  * (But only does -u, because who still cares about "ed"?)
  *
  * TODO:
  * -b backup
  * -l treat all whitespace as a single space
  * -N ignore already applied
  * -d chdir first
  * -D define wrap #ifdef and #ifndef around changes
  * -o outfile output here instead of in place
  * -r rejectfile write rejected hunks to this file
  *
  * -E remove empty files --remove-empty-files
  * -f force (no questions asked)
  * -F fuzz (number, default 2)
  * [file] which file to patch

 USE_PATCH(NEWTOY(patch, "up#i:R", TOYFLAG_USR|TOYFLAG_BIN))

 config PATCH
 	bool "patch"
 	default y
 	help
 	  usage: patch [-i file] [-p depth] [-Ru]

 	  Apply a unified diff to one or more files.

 	  -i	Input file (defaults=stdin)
 	  -p	number of '/' to strip from start of file paths (default=all)
 	  -R	Reverse patch.
 	  -u	Ignored (only handles "unified" diffs)

 	  This version of patch only handles unified diffs, and only modifies
 	  a file when all all hunks to that file apply.  Patch prints failed
 	  hunks to stderr, and exits with nonzero status if any hunks fail.

 	  A file compared against /dev/null (or with a date in 1969) is
 	  created/deleted as appropriate.
 */

 #include "toys.h"

 DEFINE_GLOBALS(
 	char *infile;
 	long prefix;

 	struct double_list *plines, *flines;
 	long oldline, oldlen, newline, newlen, linenum;
 	int context, state, filein, fileout, filepatch, hunknum;
 	char *tempname, *oldname;
 )

 #define TT this.patch

 #define FLAG_REVERSE 1
 #define FLAG_PATHLEN 4

 static void do_line(void *data)
 {
 	struct double_list *dlist = (struct double_list *)data;

 	if (TT.state && *dlist->data != TT.state)
 		fdprintf(TT.state == 2 ? 2 : TT.fileout,
 			"%s\n", dlist->data+(TT.state>2 ? 1 : 0));

 	free(dlist->data);
 	free(data);
 }

 static void finish_oldfile(void)
 {
 	if (TT.tempname) replace_tempfile(TT.filein, TT.fileout, &TT.tempname);
 }

 static void fail_hunk(void)
 {
 	if (!TT.plines) return;
 	TT.plines->prev->next = 0;

 	fdprintf(2, "Hunk %d FAILED.\n", TT.hunknum);
 	toys.exitval = 1;

 	// If we got to this point, we've seeked to the end.  Discard changes to
 	// this file and advance to next file.

 	TT.state = 2;
 	llist_free(TT.plines, do_line);
 	TT.plines = NULL;
 	delete_tempfile(TT.filein, TT.fileout, &TT.tempname);
 	TT.filein = -1;
 }

 static void apply_hunk(void)
 {
 	struct double_list *plist, *buf = NULL, *check;
 	int i = 0, backwards = 0, matcheof = 0,
 		reverse = toys.optflags & FLAG_REVERSE;

 	// Break doubly linked list so we can use singly linked traversal function.
 	TT.plines->prev->next = NULL;

 	// Match EOF if there aren't as many ending context lines as beginning
 	for (plist = TT.plines; plist; plist = plist->next) {
 		if (plist->data[0]==' ') i++;
 		else i = 0;
 	}
 	if (i < TT.context) matcheof++;

 	// Search for a place to apply this hunk.  Match all context lines and
 	// lines to be removed.
 	plist = TT.plines;
 	buf = NULL;
 	i = 0;

 	// Start of for loop
 	if (TT.context) for (;;) {
 		char *data = get_line(TT.filein);

 		TT.linenum++;

 		// Skip lines of the hunk we'd be adding.
 		while (plist && *plist->data == "+-"[reverse]) {
 			if (data && !strcmp(data, plist->data+1)) {
 				if (++backwards == TT.context)
 					fdprintf(2,"Possibly reversed hunk %d at %ld\n",
 						TT.hunknum, TT.linenum);
 			} else backwards=0;
 			plist = plist->next;
 		}

 		// Is this EOF?
 		if (!data) {
 			// Does this hunk need to match EOF?
 			if (!plist && matcheof) break;

 			// File ended before we found a place for this hunk.
 			fail_hunk();
 			goto done;
 		}
 		check = dlist_add(&buf, data);

 		// todo: teach the strcmp() to ignore whitespace.

 		for (;;) {
 			// If we hit the end of a hunk that needed EOF and this isn't EOF,
 			// or next line doesn't match, flush first line of buffered data and
 			// recheck match until we find a new match or run out of buffer.

 			if (!plist || strcmp(check->data, plist->data+1)) {
 				// First line isn't a match, write it out.
 				TT.state = 1;
 				check = llist_pop(&buf);
 				check->prev->next = buf;
 				buf->prev = check->prev;
 				do_line(check);
 				plist = TT.plines;

 				// Out of buffered lines?
 				if (check==buf) {
 					buf = 0;
 					break;
 				}
 				check = buf;
 			} else {
 				// This line matches.  Advance plist, detect successful match.
 				plist = plist->next;
 				if (!plist && !matcheof) goto out;
 				check = check->next;
 				if (check == buf) break;
 			}
 		}
 	}
 out:
 	// Got it.  Emit changed data.
 	TT.state = "-+"[reverse];
 	llist_free(TT.plines, do_line);
 	TT.plines = NULL;
 done:
 	TT.state = 0;
 	if (buf) {
 		buf->prev->next = NULL;
 		llist_free(buf, do_line);
 	}
 }

 // state 0: Not in a hunk, look for +++.
 // state 1: Found +++ file indicator, look for @@
 // state 2: In hunk: counting initial context lines
 // state 3: In hunk: getting body

 void patch_main(void)
 {
 	if (TT.infile) TT.filepatch = xopen(TT.infile, O_RDONLY);
 	TT.filein = TT.fileout = -1;

 	// Loop through the lines in the patch
 	for(;;) {
 		char *patchline;

 		patchline = get_line(TT.filepatch);
 		if (!patchline) break;

 		// Are we processing a hunk?
 		if (TT.state >= 2) {
 			if (*patchline==' ' || *patchline=='+' || *patchline=='-') {
 				dlist_add(&TT.plines, patchline);

 				if (*patchline != '+') TT.oldlen--;
 				if (*patchline != '-') TT.newlen--;

 				// Context line?
 				if (*patchline==' ' && TT.state==2) TT.context++;
 				else TT.state=3;

 				if (!TT.oldlen && !TT.newlen) apply_hunk();
 				continue;
 			}
 			fail_hunk();
 			TT.state = 0;
 			continue;
 		}

 		// Open a new file?
 		if (!strncmp("--- ", patchline, 4)) {
 			char *s;
 			free(TT.oldname);

 			// Trim date from end of filename (if any).  We don't care.
 			for (s = patchline+4; *s && *s!='\t'; s++)
 				if (*s=='\\' && s[1]) s++;
 			if (!strncmp(s, "\t1969-12-31", 10))
 				TT.oldname = xstrdup("/dev/null");
 			else {
 				*s = 0;
 				TT.oldname = xstrdup(patchline+4);
 			}
 		} else if (!strncmp("+++ ", patchline, 4)) {
 			int i = 0, del = 0;
 			char *s, *start;

 			finish_oldfile();

 			// Trim date from end of filename (if any).  We don't care.
 			for (s = start = patchline+4; *s && *s!='\t'; s++)
 				if (*s=='\\' && s[1]) s++;
 			if (!strncmp(s, "\t1969-12-31", 10)) start = "/dev/null";
 			*s = 0;

 			// If new file is /dev/null (before -p), we're deleting oldname
 			if (!strcmp(start, "/dev/null")) {
 				start = TT.oldname;
 				del++;
 			} else start = patchline+4;

 			// handle -p path truncation.
 			for (s = start; *s;) {
 				if ((toys.optflags & FLAG_PATHLEN) && TT.prefix == i) break;
 				if (*(s++)=='/') {
 					start = s;
 					i++;
 				}
 			}

 			if (del) xunlink(TT.oldname);
 			// If we've got a file to open, do so.
 			else if (!(toys.optflags & FLAG_PATHLEN) || i <= TT.prefix) {
 				// If the old file was null, we're creating a new one.
 				if (!strcmp(TT.oldname, "/dev/null")) {
 					printf("creating %s\n", start);
 					s = strrchr(start, '/');
 					if (s) {
 						*s = 0;
 						xmkpath(start, -1);
 						*s = '/';
 					}
 					TT.filein = xcreate(start, O_CREAT|O_EXCL|O_RDWR, 0666);
 				} else {
 					printf("patching %s\n", start);
 					TT.filein = xopen(start, O_RDWR);
 				}
 				TT.fileout = copy_tempfile(TT.filein, start, &TT.tempname);
 				TT.state = 1;
 				TT.context = 0;
 				TT.linenum = 0;
 				TT.hunknum = 0;
 			}

 		// Start a new hunk?
 		// Test filein rather than state to report only the first failed hunk.
 		} else if (TT.filein!=-1 && !strncmp("@@ -", patchline, 4) &&
 			4 == sscanf(patchline+4, "%ld,%ld +%ld,%ld", &TT.oldline,
 				&TT.oldlen, &TT.newline, &TT.newlen))
 		{
 			TT.context = 0;
 			TT.hunknum++;
 			TT.state = 2;
 			continue;
 		}

 		// If we didn't continue above, discard this line.
 		free(patchline);
 	}

 	finish_oldfile();

 	if (CFG_TOYBOX_FREE) {
 		close(TT.filepatch);
 		free(TT.oldname);
 	}
 }
	/* vi: set sw=4 ts=4:
	*
	* patch.c - Apply a "universal" diff.
	*
	* Copyright 2007 Rob Landley <rob@landley.net>
	*
	* see http://www.opengroup.org/onlinepubs/009695399/utilities/patch.html
	* (But only does -u, because who still cares about "ed"?)
	*
	* TODO:
	* -b backup
	* -l treat all whitespace as a single space
	* -N ignore already applied
	* -d chdir first
	* -D define wrap #ifdef and #ifndef around changes
	* -o outfile output here instead of in place
	* -r rejectfile write rejected hunks to this file
	*
	* -E remove empty files --remove-empty-files
	* -f force (no questions asked)
	* -F fuzz (number, default 2)
	* [file] which file to patch

	USE_PATCH(NEWTOY(patch, "up#i:R", TOYFLAG_USR\|TOYFLAG_BIN))

	config PATCH
	bool "patch"
	default y
	help
	usage: patch [-i file] [-p depth] [-Ru]

	Apply a unified diff to one or more files.

	-i Input file (defaults=stdin)
	-p number of '/' to strip from start of file paths (default=all)
	-R Reverse patch.
	-u Ignored (only handles "unified" diffs)

	This version of patch only handles unified diffs, and only modifies
	a file when all all hunks to that file apply. Patch prints failed
	hunks to stderr, and exits with nonzero status if any hunks fail.

	A file compared against /dev/null (or with a date in 1969) is
	created/deleted as appropriate.
	*/

	#include "toys.h"

	DEFINE_GLOBALS(
	char *infile;
	long prefix;

	struct double_list plines, flines;
	long oldline, oldlen, newline, newlen, linenum;
	int context, state, filein, fileout, filepatch, hunknum;
	char tempname, oldname;
	)

	#define TT this.patch

	#define FLAG_REVERSE 1
	#define FLAG_PATHLEN 4

	static void do_line(void *data)
	{
	struct double_list dlist = (struct double_list )data;

	if (TT.state && *dlist->data != TT.state)
	fdprintf(TT.state == 2 ? 2 : TT.fileout,
	"%s\n", dlist->data+(TT.state>2 ? 1 : 0));

	free(dlist->data);
	free(data);
	}

	static void finish_oldfile(void)
	{
	if (TT.tempname) replace_tempfile(TT.filein, TT.fileout, &TT.tempname);
	}

	static void fail_hunk(void)
	{
	if (!TT.plines) return;
	TT.plines->prev->next = 0;

	fdprintf(2, "Hunk %d FAILED.\n", TT.hunknum);
	toys.exitval = 1;

	// If we got to this point, we've seeked to the end. Discard changes to
	// this file and advance to next file.

	TT.state = 2;
	llist_free(TT.plines, do_line);
	TT.plines = NULL;
	delete_tempfile(TT.filein, TT.fileout, &TT.tempname);
	TT.filein = -1;
	}

	static void apply_hunk(void)
	{
	struct double_list plist, buf = NULL, *check;
	int i = 0, backwards = 0, matcheof = 0,
	reverse = toys.optflags & FLAG_REVERSE;

	// Break doubly linked list so we can use singly linked traversal function.
	TT.plines->prev->next = NULL;

	// Match EOF if there aren't as many ending context lines as beginning
	for (plist = TT.plines; plist; plist = plist->next) {
	if (plist->data[0]==' ') i++;
	else i = 0;
	}
	if (i < TT.context) matcheof++;

	// Search for a place to apply this hunk. Match all context lines and
	// lines to be removed.
	plist = TT.plines;
	buf = NULL;
	i = 0;

	// Start of for loop
	if (TT.context) for (;;) {
	char *data = get_line(TT.filein);

	TT.linenum++;

	// Skip lines of the hunk we'd be adding.
	while (plist && *plist->data == "+-"[reverse]) {
	if (data && !strcmp(data, plist->data+1)) {
	if (++backwards == TT.context)
	fdprintf(2,"Possibly reversed hunk %d at %ld\n",
	TT.hunknum, TT.linenum);
	} else backwards=0;
	plist = plist->next;
	}

	// Is this EOF?
	if (!data) {
	// Does this hunk need to match EOF?
	if (!plist && matcheof) break;

	// File ended before we found a place for this hunk.
	fail_hunk();
	goto done;
	}
	check = dlist_add(&buf, data);

	// todo: teach the strcmp() to ignore whitespace.

	for (;;) {
	// If we hit the end of a hunk that needed EOF and this isn't EOF,
	// or next line doesn't match, flush first line of buffered data and
	// recheck match until we find a new match or run out of buffer.

	if (!plist \|\| strcmp(check->data, plist->data+1)) {
	// First line isn't a match, write it out.
	TT.state = 1;
	check = llist_pop(&buf);
	check->prev->next = buf;
	buf->prev = check->prev;
	do_line(check);
	plist = TT.plines;

	// Out of buffered lines?
	if (check==buf) {
	buf = 0;
	break;
	}
	check = buf;
	} else {
	// This line matches. Advance plist, detect successful match.
	plist = plist->next;
	if (!plist && !matcheof) goto out;
	check = check->next;
	if (check == buf) break;
	}
	}
	}
	out:
	// Got it. Emit changed data.
	TT.state = "-+"[reverse];
	llist_free(TT.plines, do_line);
	TT.plines = NULL;
	done:
	TT.state = 0;
	if (buf) {
	buf->prev->next = NULL;
	llist_free(buf, do_line);
	}
	}

	// state 0: Not in a hunk, look for +++.
	// state 1: Found +++ file indicator, look for @@
	// state 2: In hunk: counting initial context lines
	// state 3: In hunk: getting body

	void patch_main(void)
	{
	if (TT.infile) TT.filepatch = xopen(TT.infile, O_RDONLY);
	TT.filein = TT.fileout = -1;

	// Loop through the lines in the patch
	for(;;) {
	char *patchline;

	patchline = get_line(TT.filepatch);
	if (!patchline) break;

	// Are we processing a hunk?
	if (TT.state >= 2) {
	if (patchline==' ' \|\| patchline=='+' \|\| *patchline=='-') {
	dlist_add(&TT.plines, patchline);

	if (*patchline != '+') TT.oldlen--;
	if (*patchline != '-') TT.newlen--;

	// Context line?
	if (*patchline==' ' && TT.state==2) TT.context++;
	else TT.state=3;

	if (!TT.oldlen && !TT.newlen) apply_hunk();
	continue;
	}
	fail_hunk();
	TT.state = 0;
	continue;
	}

	// Open a new file?
	if (!strncmp("--- ", patchline, 4)) {
	char *s;
	free(TT.oldname);

	// Trim date from end of filename (if any). We don't care.
	for (s = patchline+4; s && s!='\t'; s++)
	if (*s=='\\' && s[1]) s++;
	if (!strncmp(s, "\t1969-12-31", 10))
	TT.oldname = xstrdup("/dev/null");
	else {
	*s = 0;
	TT.oldname = xstrdup(patchline+4);
	}
	} else if (!strncmp("+++ ", patchline, 4)) {
	int i = 0, del = 0;
	char s, start;

	finish_oldfile();

	// Trim date from end of filename (if any). We don't care.
	for (s = start = patchline+4; s && s!='\t'; s++)
	if (*s=='\\' && s[1]) s++;
	if (!strncmp(s, "\t1969-12-31", 10)) start = "/dev/null";
	*s = 0;

	// If new file is /dev/null (before -p), we're deleting oldname
	if (!strcmp(start, "/dev/null")) {
	start = TT.oldname;
	del++;
	} else start = patchline+4;

	// handle -p path truncation.
	for (s = start; *s;) {
	if ((toys.optflags & FLAG_PATHLEN) && TT.prefix == i) break;
	if (*(s++)=='/') {
	start = s;
	i++;
	}
	}

	if (del) xunlink(TT.oldname);
	// If we've got a file to open, do so.
	else if (!(toys.optflags & FLAG_PATHLEN) \|\| i <= TT.prefix) {
	// If the old file was null, we're creating a new one.
	if (!strcmp(TT.oldname, "/dev/null")) {
	printf("creating %s\n", start);
	s = strrchr(start, '/');
	if (s) {
	*s = 0;
	xmkpath(start, -1);
	*s = '/';
	}
	TT.filein = xcreate(start, O_CREAT\|O_EXCL\|O_RDWR, 0666);
	} else {
	printf("patching %s\n", start);
	TT.filein = xopen(start, O_RDWR);
	}
	TT.fileout = copy_tempfile(TT.filein, start, &TT.tempname);
	TT.state = 1;
	TT.context = 0;
	TT.linenum = 0;
	TT.hunknum = 0;
	}

	// Start a new hunk?
	// Test filein rather than state to report only the first failed hunk.
	} else if (TT.filein!=-1 && !strncmp("@@ -", patchline, 4) &&
	4 == sscanf(patchline+4, "%ld,%ld +%ld,%ld", &TT.oldline,
	&TT.oldlen, &TT.newline, &TT.newlen))
	{
	TT.context = 0;
	TT.hunknum++;
	TT.state = 2;
	continue;
	}

	// If we didn't continue above, discard this line.
	free(patchline);
	}

	finish_oldfile();

	if (CFG_TOYBOX_FREE) {
	close(TT.filepatch);
	free(TT.oldname);
	}
	}