X-Git-Url: https://git.verplant.org/?a=blobdiff_plain;f=diff.c;h=95488cdd9f026f897c688428f7090aa59d099bad;hb=fcfda02bc7e3a9dacf63fa43df8eee530a471f96;hp=dcefe983afd8a0c32fd9ba6d1c8abc6cb9bf6736;hpb=86436c28289eedd2ee9b7f9c872a0ed039866a0f;p=git.git

diff --git a/diff.c b/diff.c
index dcefe983..95488cdd 100644
--- a/diff.c
+++ b/diff.c
@@ -1,24 +1,38 @@
+/*
+ * Copyright (C) 2005 Junio C Hamano
+ */
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
 #include "cache.h"
 #include "diff.h"
 
-static char *diff_cmd = "diff -L 'k/%s' -L 'l/%s' ";
-static char *diff_opts = "-p -u";
-static char *diff_arg_forward  = " - '%s'";
-static char *diff_arg_reverse  = " '%s' -";
+static char *diff_opts = "-pu";
 
-void prepare_diff_cmd(void)
+static const char *external_diff(void)
 {
+	static char *external_diff_cmd = NULL;
+	static int done_preparing = 0;
+
+	if (done_preparing)
+		return external_diff_cmd;
+
 	/*
 	 * Default values above are meant to match the
 	 * Linux kernel development style.  Examples of
 	 * alternative styles you can specify via environment
 	 * variables are:
 	 *
-	 * GIT_DIFF_CMD="diff -L '%s' -L '%s'"
 	 * GIT_DIFF_OPTS="-c";
 	 */
-	diff_cmd = getenv("GIT_DIFF_CMD") ? : diff_cmd;
+	if (getenv("GIT_EXTERNAL_DIFF"))
+		external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
+
+	/* In case external diff fails... */
 	diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;
+
+	done_preparing = 1;
+	return external_diff_cmd;
 }
 
 /* Help to copy the thing properly quoted for the shell safety.
@@ -43,8 +57,7 @@ static char *sq_expand(const char *src)
 		if (*cp == '\'')
 			cnt += 3;
 
-	if (! (buf = malloc(cnt)))
-	    return buf;
+	buf = xmalloc(cnt);
 	bp = buf;
 	while ((c = *src++)) {
 		if (c != '\'')
@@ -58,49 +71,336 @@ static char *sq_expand(const char *src)
 	return buf;
 }
 
-void show_differences(const char *name, /* filename on the filesystem */
-		      const char *label, /* diff label to use */
-		      void *old_contents, /* contents in core */
-		      unsigned long long old_size, /* size in core */
-		      int reverse /* 0: diff core file
-				     1: diff file core */)
+static struct diff_tempfile {
+	const char *name;
+	char hex[41];
+	char mode[10];
+	char tmp_path[50];
+} diff_temp[2];
+
+static void builtin_diff(const char *name,
+			 struct diff_tempfile *temp)
+{
+	int i, next_at;
+	const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
+	const char *diff_arg  = "'%s' '%s'||:"; /* "||:" is to return 0 */
+	const char *input_name_sq[2];
+	const char *path0[2];
+	const char *path1[2];
+	const char *name_sq = sq_expand(name);
+	char *cmd;
+	
+	/* diff_cmd and diff_arg have 6 %s in total which makes
+	 * the sum of these strings 12 bytes larger than required.
+	 * we use 2 spaces around diff-opts, and we need to count
+	 * terminating NUL, so we subtract 9 here.
+	 */
+	int cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
+			strlen(diff_arg) - 9);
+	for (i = 0; i < 2; i++) {
+		input_name_sq[i] = sq_expand(temp[i].name);
+		if (!strcmp(temp[i].name, "/dev/null")) {
+			path0[i] = "/dev/null";
+			path1[i] = "";
+		} else {
+			path0[i] = i ? "b/" : "a/";
+			path1[i] = name_sq;
+		}
+		cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
+			     strlen(input_name_sq[i]));
+	}
+
+	cmd = xmalloc(cmd_size);
+
+	next_at = 0;
+	next_at += snprintf(cmd+next_at, cmd_size-next_at,
+			    diff_cmd,
+			    path0[0], path1[0], path0[1], path1[1]);
+	next_at += snprintf(cmd+next_at, cmd_size-next_at,
+			    " %s ", diff_opts);
+	next_at += snprintf(cmd+next_at, cmd_size-next_at,
+			    diff_arg, input_name_sq[0], input_name_sq[1]);
+
+	if (!path1[0][0])
+		printf("Created: %s (mode:%s)\n", name, temp[1].mode);
+	else if (!path1[1][0])
+		printf("Deleted: %s\n", name);
+	else if (strcmp(temp[0].mode, temp[1].mode)) {
+		printf("Mode changed: %s (%s->%s)\n", name,
+		       temp[0].mode, temp[1].mode);
+		/* Be careful.  We do not want to diff between
+		 * symlink and a file.
+		 */
+		if (strncmp(temp[0].mode, "120", 3) !=
+		    strncmp(temp[1].mode, "120", 3))
+			exit(0);
+	}
+	fflush(NULL);
+	execlp("/bin/sh","sh", "-c", cmd, NULL);
+}
+
+/*
+ * Given a name and sha1 pair, if the dircache tells us the file in
+ * the work tree has that object contents, return true, so that
+ * prepare_temp_file() does not have to inflate and extract.
+ */
+static int work_tree_matches(const char *name, const unsigned char *sha1)
 {
-	FILE *f;
-	char *name_sq = sq_expand(name);
-	const char *label_sq = (name != label) ? sq_expand(label) : name_sq;
-	char *diff_arg = reverse ? diff_arg_reverse : diff_arg_forward;
-	int cmd_size = strlen(name_sq) + strlen(label_sq) * 2 +
-		strlen(diff_cmd) + strlen(diff_opts) + strlen(diff_arg);
-	char *cmd = malloc(cmd_size);
-	int next_at;
-
-	fflush(stdout);
-	next_at = snprintf(cmd, cmd_size, diff_cmd, label_sq, label_sq);
-	next_at += snprintf(cmd+next_at, cmd_size-next_at, "%s", diff_opts);
-	next_at += snprintf(cmd+next_at, cmd_size-next_at, diff_arg, name_sq);
-	f = popen(cmd, "w");
-	if (old_size)
-		fwrite(old_contents, old_size, 1, f);
-	pclose(f);
-	if (label_sq != name_sq)
-		free((void*)label_sq); /* constness */
-	free(name_sq);
-	free(cmd);
+	struct cache_entry *ce;
+	struct stat st;
+	int pos, len;
+	
+	/* We do not read the cache ourselves here, because the
+	 * benchmark with my previous version that always reads cache
+	 * shows that it makes things worse for diff-tree comparing
+	 * two linux-2.6 kernel trees in an already checked out work
+	 * tree.  This is because most diff-tree comparison deals with
+	 * only a small number of files, while reading the cache is
+	 * expensive for a large project, and its cost outweighs the
+	 * savings we get by not inflating the object to a temporary
+	 * file.  Practically, this code only helps when we are used
+	 * by diff-cache --cached, which does read the cache before
+	 * calling us.
+	 */ 
+	if (!active_cache)
+		return 0;
+
+	len = strlen(name);
+	pos = cache_name_pos(name, len);
+	if (pos < 0)
+		return 0;
+	ce = active_cache[pos];
+	if ((lstat(name, &st) < 0) ||
+	    !S_ISREG(st.st_mode) ||
+	    cache_match_stat(ce, &st) ||
+	    memcmp(sha1, ce->sha1, 20))
+		return 0;
+	return 1;
 }
 
-void show_diff_empty(const unsigned char *sha1,
-		     const char *name,
-		     int reverse)
+static void prep_temp_blob(struct diff_tempfile *temp,
+			   void *blob,
+			   unsigned long size,
+			   unsigned char *sha1,
+			   int mode)
 {
-	char *old;
-	unsigned long int size;
-	unsigned char type[20];
-
-	old = read_sha1_file(sha1, type, &size);
-	if (! old) {
-		error("unable to read blob object for %s (%s)", name,
-		      sha1_to_hex(sha1));
+	int fd;
+
+	strcpy(temp->tmp_path, ".diff_XXXXXX");
+	fd = mkstemp(temp->tmp_path);
+	if (fd < 0)
+		die("unable to create temp-file");
+	if (write(fd, blob, size) != size)
+		die("unable to write temp-file");
+	close(fd);
+	temp->name = temp->tmp_path;
+	strcpy(temp->hex, sha1_to_hex(sha1));
+	temp->hex[40] = 0;
+	sprintf(temp->mode, "%06o", mode);
+}
+
+static void prepare_temp_file(const char *name,
+			      struct diff_tempfile *temp,
+			      struct diff_spec *one)
+{
+	static unsigned char null_sha1[20] = { 0, };
+	int use_work_tree = 0;
+
+	if (!one->file_valid) {
+	not_a_valid_file:
+		/* A '-' entry produces this for file-2, and
+		 * a '+' entry produces this for file-1.
+		 */
+		temp->name = "/dev/null";
+		strcpy(temp->hex, ".");
+		strcpy(temp->mode, ".");
 		return;
 	}
-	show_differences("/dev/null", name, old, size, reverse);
+
+	if (one->sha1_valid &&
+	    (!memcmp(one->blob_sha1, null_sha1, sizeof(null_sha1)) ||
+	     work_tree_matches(name, one->blob_sha1)))
+		use_work_tree = 1;
+
+	if (!one->sha1_valid || use_work_tree) {
+		struct stat st;
+		temp->name = name;
+		if (lstat(temp->name, &st) < 0) {
+			if (errno == ENOENT)
+				goto not_a_valid_file;
+			die("stat(%s): %s", temp->name, strerror(errno));
+		}
+		if (S_ISLNK(st.st_mode)) {
+			int ret;
+			char *buf, buf_[1024];
+			buf = ((sizeof(buf_) < st.st_size) ?
+			       xmalloc(st.st_size) : buf_);
+			ret = readlink(name, buf, st.st_size);
+			if (ret < 0)
+				die("readlink(%s)", name);
+			prep_temp_blob(temp, buf, st.st_size,
+				       (one->sha1_valid ?
+					one->blob_sha1 : null_sha1),
+				       (one->sha1_valid ?
+					one->mode : S_IFLNK));
+		}
+		else {
+			if (!one->sha1_valid)
+				strcpy(temp->hex, sha1_to_hex(null_sha1));
+			else
+				strcpy(temp->hex, sha1_to_hex(one->blob_sha1));
+			sprintf(temp->mode, "%06o",
+				S_IFREG |ce_permissions(st.st_mode));
+		}
+		return;
+	}
+	else {
+		void *blob;
+		char type[20];
+		unsigned long size;
+
+		blob = read_sha1_file(one->blob_sha1, type, &size);
+		if (!blob || strcmp(type, "blob"))
+			die("unable to read blob object for %s (%s)",
+			    name, sha1_to_hex(one->blob_sha1));
+		prep_temp_blob(temp, blob, size, one->blob_sha1, one->mode);
+		free(blob);
+	}
+}
+
+static void remove_tempfile(void)
+{
+	int i;
+
+	for (i = 0; i < 2; i++)
+		if (diff_temp[i].name == diff_temp[i].tmp_path) {
+			unlink(diff_temp[i].name);
+			diff_temp[i].name = NULL;
+		}
+}
+
+static void remove_tempfile_on_signal(int signo)
+{
+	remove_tempfile();
+}
+
+/* An external diff command takes:
+ *
+ * diff-cmd name infile1 infile1-sha1 infile1-mode \
+ *               infile2 infile2-sha1 infile2-mode.
+ *
+ */
+void run_external_diff(const char *name,
+		       struct diff_spec *one,
+		       struct diff_spec *two)
+{
+	struct diff_tempfile *temp = diff_temp;
+	pid_t pid;
+	int status;
+	static int atexit_asked = 0;
+
+	if (one && two) {
+		prepare_temp_file(name, &temp[0], one);
+		prepare_temp_file(name, &temp[1], two);
+		if (! atexit_asked &&
+		    (temp[0].name == temp[0].tmp_path ||
+		     temp[1].name == temp[1].tmp_path)) {
+			atexit_asked = 1;
+			atexit(remove_tempfile);
+		}
+		signal(SIGINT, remove_tempfile_on_signal);
+	}
+
+	fflush(NULL);
+	pid = fork();
+	if (pid < 0)
+		die("unable to fork");
+	if (!pid) {
+		const char *pgm = external_diff();
+		if (pgm) {
+			if (one && two)
+				execlp(pgm, pgm,
+				       name,
+				       temp[0].name, temp[0].hex, temp[0].mode,
+				       temp[1].name, temp[1].hex, temp[1].mode,
+				       NULL);
+			else
+				execlp(pgm, pgm, name, NULL);
+		}
+		/*
+		 * otherwise we use the built-in one.
+		 */
+		if (one && two)
+			builtin_diff(name, temp);
+		else
+			printf("* Unmerged path %s\n", name);
+		exit(0);
+	}
+	if (waitpid(pid, &status, 0) < 0 ||
+	    !WIFEXITED(status) || WEXITSTATUS(status)) {
+		/* Earlier we did not check the exit status because
+		 * diff exits non-zero if files are different, and
+		 * we are not interested in knowing that.  It was a
+		 * mistake which made it harder to quit a diff-*
+		 * session that uses the git-apply-patch-script as
+		 * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
+		 * should also exit non-zero only when it wants to
+		 * abort the entire diff-* session.
+		 */
+		remove_tempfile();
+		fprintf(stderr, "external diff died, stopping at %s.\n", name);
+		exit(1);
+	}
+	remove_tempfile();
+}
+
+void diff_addremove(int addremove, unsigned mode,
+		    const unsigned char *sha1,
+		    const char *base, const char *path)
+{
+	char concatpath[PATH_MAX];
+	struct diff_spec spec[2], *one, *two;
+
+	memcpy(spec[0].blob_sha1, sha1, 20);
+	spec[0].mode = mode;
+	spec[0].sha1_valid = spec[0].file_valid = 1;
+	spec[1].file_valid = 0;
+
+	if (addremove == '+') {
+		one = spec + 1; two = spec;
+	} else {
+		one = spec; two = one + 1;
+	}
+	
+	if (path) {
+		strcpy(concatpath, base);
+		strcat(concatpath, path);
+	}
+	run_external_diff(path ? concatpath : base, one, two);
+}
+
+void diff_change(unsigned old_mode, unsigned new_mode,
+		 const unsigned char *old_sha1,
+		 const unsigned char *new_sha1,
+		 const char *base, const char *path) {
+	char concatpath[PATH_MAX];
+	struct diff_spec spec[2];
+
+	memcpy(spec[0].blob_sha1, old_sha1, 20);
+	spec[0].mode = old_mode;
+	memcpy(spec[1].blob_sha1, new_sha1, 20);
+	spec[1].mode = new_mode;
+	spec[0].sha1_valid = spec[0].file_valid = 1;
+	spec[1].sha1_valid = spec[1].file_valid = 1;
+
+	if (path) {
+		strcpy(concatpath, base);
+		strcat(concatpath, path);
+	}
+	run_external_diff(path ? concatpath : base, &spec[0], &spec[1]);
+}
+
+void diff_unmerge(const char *path)
+{
+	run_external_diff(path, NULL, NULL);
 }