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authorJunio C Hamano <junkio@cox.net>2005-04-26 01:22:47 (GMT)
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-26 01:22:47 (GMT)
commit86436c28289eedd2ee9b7f9c872a0ed039866a0f (patch)
tree780ecf60c2d10084ab26758c093319d0c6c86480 /diff.c
parentab7df1874d87d3f7494397442e67e900b580a346 (diff)
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[PATCH] Split external diff command interface to a separate file.
With this patch, the non-core'ish part of show-diff command that invokes an external "diff" comand to obtain patches is split into a separate file. The next patch will introduce a new command, diff-tree-helper, which uses this common diff interface to format diff-tree and diff-cache output into a patch form. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'diff.c')
-rw-r--r--diff.c106
1 files changed, 106 insertions, 0 deletions
diff --git a/diff.c b/diff.c
new file mode 100644
index 0000000..dcefe98
--- /dev/null
+++ b/diff.c
@@ -0,0 +1,106 @@
+#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' -";
+
+void prepare_diff_cmd(void)
+{
+ /*
+ * 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;
+ diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;
+}
+
+/* Help to copy the thing properly quoted for the shell safety.
+ * any single quote is replaced with '\'', and the caller is
+ * expected to enclose the result within a single quote pair.
+ *
+ * E.g.
+ * original sq_expand result
+ * name ==> name ==> 'name'
+ * a b ==> a b ==> 'a b'
+ * a'b ==> a'\''b ==> 'a'\''b'
+ */
+static char *sq_expand(const char *src)
+{
+ static char *buf = NULL;
+ int cnt, c;
+ const char *cp;
+ char *bp;
+
+ /* count bytes needed to store the quoted string. */
+ for (cnt = 1, cp = src; *cp; cnt++, cp++)
+ if (*cp == '\'')
+ cnt += 3;
+
+ if (! (buf = malloc(cnt)))
+ return buf;
+ bp = buf;
+ while ((c = *src++)) {
+ if (c != '\'')
+ *bp++ = c;
+ else {
+ bp = strcpy(bp, "'\\''");
+ bp += 4;
+ }
+ }
+ *bp = 0;
+ 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 */)
+{
+ 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);
+}
+
+void show_diff_empty(const unsigned char *sha1,
+ const char *name,
+ int reverse)
+{
+ 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));
+ return;
+ }
+ show_differences("/dev/null", name, old, size, reverse);
+}