patch: replace it with toybox's implementation

Signed-off-by: Rob Landley <rob@landley.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 98 insertions, 66 deletions

diff --git a/editors/patch_toybox.c b/editors/patch_toybox.c
index 0e5c070e2..7f3234e66 100644
--- a/editors/patch_toybox.c
+++ b/editors/patch_toybox.c
@@ -1,4 +1,4 @@
-/* Adapted from toybox's patch. Currently unused */
+/* Adapted from toybox's patch. */
 
 /* vi: set sw=4 ts=4:
  *
@@ -23,7 +23,7 @@
  * -F fuzz (number, default 2)
  * [file] which file to patch
 
-USE_PATCH(NEWTOY(patch, "up#i:R", TOYFLAG_USR|TOYFLAG_BIN))
+USE_PATCH(NEWTOY(patch, USE_TOYBOX_DEBUG("x")"up#i:R", TOYFLAG_USR|TOYFLAG_BIN))
 
 config PATCH
 	bool "patch"
@@ -223,15 +223,16 @@ void delete_tempfile(int fdin, int fdout, char **tempname)
 
 
 struct globals {
-	struct double_list *plines;
-	long linenum;
-	int context;
-	int hunknum;
-	int filein;
-	int fileout;
-	int state;
+	char *infile;
+	long prefix;
+
+	struct double_list *current_hunk;
+	long oldline, oldlen, newline, newlen, linenum;
+	int context, state, filein, fileout, filepatch, hunknum;
 	char *tempname;
-	smallint exitval;
+
+	// was toys.foo:
+	int exitval;
 };
 #define TT (*ptr_to_globals)
 #define INIT_TT() do { \
@@ -240,12 +241,14 @@ struct globals {
 
 
 //bbox had: "p:i:RN"
-#define FLAG_STR "Rup:i:"
+#define FLAG_STR "Rup:i:x"
 /* FLAG_REVERSE must be == 1! Code uses this fact. */
 #define FLAG_REVERSE (1 << 0)
 #define FLAG_u       (1 << 1)
 #define FLAG_PATHLEN (1 << 2)
 #define FLAG_INPUT   (1 << 3)
+//non-standard:
+#define FLAG_DEBUG   (1 << 4)
 
 // Dispose of a line of input, either by writing it out or discarding it.
 
@@ -254,6 +257,8 @@ struct globals {
 // state = 3: write whole line to fileout
 // state > 3: write line+1 to fileout when *line != state
 
+#define PATCH_DEBUG (option_mask32 & FLAG_DEBUG)
+
 static void do_line(void *data)
 {
 	struct double_list *dlist = (struct double_list *)data;
@@ -262,6 +267,8 @@ static void do_line(void *data)
 		fdprintf(TT.state == 2 ? 2 : TT.fileout,
 			"%s\n", dlist->data+(TT.state>3 ? 1 : 0));
 
+	if (PATCH_DEBUG) fdprintf(2, "DO %d: %s\n", TT.state, dlist->data);
+
 	free(dlist->data);
 	free(data);
 }
@@ -274,94 +281,118 @@ static void finish_oldfile(void)
 
 static void fail_hunk(void)
 {
-	if (!TT.plines) return;
-	TT.plines->prev->next = 0;
+	if (!TT.current_hunk) return;
+	TT.current_hunk->prev->next = 0;
 
-	fdprintf(2, "Hunk %d FAILED.\n", TT.hunknum);
+	fdprintf(2, "Hunk %d FAILED %ld/%ld.\n", TT.hunknum, TT.oldline, TT.newline);
 	TT.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;
-	TOY_llist_free(TT.plines, do_line);
-	TT.plines = NULL;
+	TOY_llist_free(TT.current_hunk, do_line);
+	TT.current_hunk = NULL;
 	delete_tempfile(TT.filein, TT.fileout, &TT.tempname);
 	TT.state = 0;
 }
 
-static int apply_hunk(void)
+// Given a hunk of a unified diff, make the appropriate change to the file.
+// This does not use the location information, but instead treats a hunk
+// as a sort of regex.  Copies data from input to output until it finds
+// the change to be made, then outputs the changed data and returns.
+// (Finding EOF first is an error.)  This is a single pass operation, so
+// multiple hunks must occur in order in the file.
+
+static int apply_one_hunk(void)
 {
 	struct double_list *plist, *buf = NULL, *check;
-	int i = 0, backwards = 0, matcheof = 0,
-		reverse = option_mask32 & FLAG_REVERSE;
+	int matcheof = 0, reverse = option_mask32 & FLAG_REVERSE, backwarn = 0;
 
 	// Break doubly linked list so we can use singly linked traversal function.
-	TT.plines->prev->next = NULL;
+	TT.current_hunk->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;
+	for (plist = TT.current_hunk; plist; plist = plist->next) {
+		if (plist->data[0]==' ') matcheof++;
+		else matcheof = 0;
+		if (PATCH_DEBUG) fdprintf(2, "HUNK:%s\n", plist->data);
 	}
-	if (i < TT.context) matcheof++;
+	matcheof = matcheof < TT.context;
 
-	// Search for a place to apply this hunk.  Match all context lines and
-	// lines to be removed.
-	plist = TT.plines;
-	buf = NULL;
-	i = 0;
+	if (PATCH_DEBUG) fdprintf(2,"MATCHEOF=%c\n", matcheof ? 'Y' : 'N');
 
-	// Start of for loop
+	// Loop through input data searching for this hunk.  Match all context
+	// lines and all lines to be removed until we've found the end of a
+	// complete hunk.
+	plist = TT.current_hunk;
+	buf = NULL;
 	if (TT.context) for (;;) {
 		char *data = get_line(TT.filein);
 
 		TT.linenum++;
 
-		// Skip lines of the hunk we'd be adding.
+		// Figure out which line of hunk to compare with next.  (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)
+				if (!backwarn) {
 					fdprintf(2,"Possibly reversed hunk %d at %ld\n",
 						TT.hunknum, TT.linenum);
-			} else backwards=0;
+					backwarn++;
+				}
+			}
 			plist = plist->next;
 		}
 
 		// Is this EOF?
 		if (!data) {
+			if (PATCH_DEBUG) fdprintf(2, "INEOF\n");
+
 			// 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;
-		}
+		} else if (PATCH_DEBUG) fdprintf(2, "IN: %s\n", data);
 		check = dlist_add(&buf, data);
 
+		// Compare this line with next expected line of hunk.
 		// 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.
+		// A match can fail because the next line doesn't match, or because
+		// we hit the end of a hunk that needed EOF, and this isn't EOF.
+
+		// If match failed, flush first line of buffered data and
+		// recheck buffered data for a new match until we find one or run
+		// out of buffer.
 
+		for (;;) {
 			if (!plist || strcmp(check->data, plist->data+1)) {
-				// First line isn't a match, write it out.
+				// Match failed.  Write out first line of buffered data and
+				// recheck remaining buffered data for a new match.
+
+				if (PATCH_DEBUG)
+					fdprintf(2, "NOT: %s\n", plist->data);
+
 				TT.state = 3;
 				check = TOY_llist_pop(&buf);
 				check->prev->next = buf;
 				buf->prev = check->prev;
 				do_line(check);
-				plist = TT.plines;
+				plist = TT.current_hunk;
 
-				// Out of buffered lines?
+				// If we've reached the end of the buffer without confirming a
+				// match, read more lines.
 				if (check==buf) {
 					buf = 0;
 					break;
 				}
 				check = buf;
 			} else {
+				if (PATCH_DEBUG)
+					fdprintf(2, "MAYBE: %s\n", plist->data);
 				// This line matches.  Advance plist, detect successful match.
 				plist = plist->next;
 				if (!plist && !matcheof) goto out;
@@ -371,10 +402,10 @@ static int apply_hunk(void)
 		}
 	}
 out:
-	// Got it.  Emit changed data.
+	// We have a match.  Emit changed data.
 	TT.state = "-+"[reverse];
-	TOY_llist_free(TT.plines, do_line);
-	TT.plines = NULL;
+	TOY_llist_free(TT.current_hunk, do_line);
+	TT.current_hunk = NULL;
 	TT.state = 1;
 done:
 	if (buf) {
@@ -385,6 +416,9 @@ done:
 	return TT.state;
 }
 
+// Read a patch file and find hunks, opening/creating/deleting files.
+// Call apply_one_hunk() on each hunk.
+
 // state 0: Not in a hunk, look for +++.
 // state 1: Found +++ file indicator, look for @@
 // state 2: In hunk: counting initial context lines
@@ -397,24 +431,20 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
 	int reverse, state = 0;
 	char *oldname = NULL, *newname = NULL;
 	char *opt_p, *opt_i;
-	int prefix;
-
-	long oldline = 0, oldlen = 0, newline = 0, newlen = 0;
 
 	INIT_TT();
 
 	opts = getopt32(argv, FLAG_STR, &opt_p, &opt_i);
 	reverse = opts & FLAG_REVERSE;
-
-	if (opts & FLAG_INPUT) xmove_fd(xopen(opt_i, O_RDONLY), STDIN_FILENO);
-	prefix = (opts & FLAG_PATHLEN) ? xatoi(opt_p) : 0; // can be negative!
+	TT.prefix = (opts & FLAG_PATHLEN) ? xatoi(opt_p) : 0; // can be negative!
+	if (opts & FLAG_INPUT) TT.filepatch = xopen(opt_i, O_RDONLY);
 	TT.filein = TT.fileout = -1;
 
 	// Loop through the lines in the patch
 	for(;;) {
 		char *patchline;
 
-		patchline = get_line(STDIN_FILENO);
+		patchline = get_line(TT.filepatch);
 		if (!patchline) break;
 
 		// Other versions of patch accept damaged patches,
@@ -427,17 +457,18 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
 		// Are we assembling a hunk?
 		if (state >= 2) {
 			if (*patchline==' ' || *patchline=='+' || *patchline=='-') {
-				dlist_add(&TT.plines, patchline);
+				dlist_add(&TT.current_hunk, patchline);
 
-				if (*patchline != '+') oldlen--;
-				if (*patchline != '-') newlen--;
+				if (*patchline != '+') TT.oldlen--;
+				if (*patchline != '-') TT.newlen--;
 
 				// Context line?
 				if (*patchline==' ' && state==2) TT.context++;
 				else state=3;
 
 				// If we've consumed all expected hunk lines, apply the hunk.
-				if (!oldlen && !newlen) state = apply_hunk();
+
+				if (!TT.oldlen && !TT.newlen) state = apply_one_hunk();
 				continue;
 			}
 			fail_hunk();
@@ -447,11 +478,11 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
 
 		// Open a new file?
 		if (!strncmp("--- ", patchline, 4) || !strncmp("+++ ", patchline, 4)) {
-			char *s, **name = &oldname;
+			char *s, **name = reverse ? &newname : &oldname;
 			int i;
 
 			if (*patchline == '+') {
-				name = &newname;
+				name = reverse ? &oldname : &newname;
 				state = 1;
 			}
 
@@ -462,7 +493,7 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
 			for (s = patchline+4; *s && *s!='\t'; s++)
 				if (*s=='\\' && s[1]) s++;
 			i = atoi(s);
-			if (i && i<=1970)
+			if (i>1900 && i<=1970)
 				*name = xstrdup("/dev/null");
 			else {
 				*s = 0;
@@ -478,8 +509,8 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
 		} else if (state == 1 && !strncmp("@@ -", patchline, 4)) {
 			int i;
 
-			i = sscanf(patchline+4, "%ld,%ld +%ld,%ld",
-					&oldline, &oldlen, &newline, &newlen);
+			i = sscanf(patchline+4, "%ld,%ld +%ld,%ld", &TT.oldline,
+						&TT.oldlen, &TT.newline, &TT.newlen);
 			if (i != 4)
 				bb_error_msg_and_die("corrupt hunk %d at %ld", TT.hunknum, TT.linenum);
 
@@ -491,22 +522,22 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
 				int oldsum, newsum, del = 0;
 				char *s, *name;
 
-				oldsum = oldline + oldlen;
-				newsum = newline + newlen;
+ 				oldsum = TT.oldline + TT.oldlen;
+				newsum = TT.newline + TT.newlen;
 
 				name = reverse ? oldname : newname;
 
 				// We're deleting oldname if new file is /dev/null (before -p)
 				// or if new hunk is empty (zero context) after patching
-				if (!strcmp(name, "/dev/null") || !(reverse ? oldsum : newsum)) {
+				if (!strcmp(name, "/dev/null") || !(reverse ? oldsum : newsum))
+				{
 					name = reverse ? newname : oldname;
 					del++;
 				}
 
 				// handle -p path truncation.
 				for (i=0, s = name; *s;) {
-					if ((option_mask32 & FLAG_PATHLEN) && prefix == i)
-						break;
+					if ((option_mask32 & FLAG_PATHLEN) && TT.prefix == i) break;
 					if (*(s++)=='/') {
 						name = s;
 						i++;
@@ -518,7 +549,7 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
 					xunlink(name);
 					state = 0;
 				// If we've got a file to open, do so.
-				} else if (!(option_mask32 & FLAG_PATHLEN) || i <= prefix) {
+				} else if (!(option_mask32 & FLAG_PATHLEN) || i <= TT.prefix) {
 					// If the old file was null, we're creating a new one.
 					if (!strcmp(oldname, "/dev/null") || !oldsum) {
 						printf("creating %s\n", name);
@@ -551,6 +582,7 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
 	finish_oldfile();
 
 	if (ENABLE_FEATURE_CLEAN_UP) {
+		close(TT.filepatch);
 		free(oldname);
 		free(newname);
 	}