git log/diff: add -G<regexp> that greps in the patch text

Teach "-G<regexp>" that is similar to "-S<regexp> --pickaxe-regexp" to the
"git diff" family of commands.  This limits the diff queue to filepairs
whose patch text actually has an added or a deleted line that matches the
given regexp.  Unlike "-S<regexp>", changing other parts of the line that
has a substring that matches the given regexp IS counted as a change, as
such a change would appear as one deletion followed by one addition in a
patch text.

Unlike -S (pickaxe) that is intended to be used to quickly detect a commit
that changes the number of occurrences of hits between the preimage and
the postimage to serve as a part of larger toolchain, this is meant to be
used as the top-level Porcelain feature.

The implementation unfortunately has to run "diff" twice if you are
running "log" family of commands to produce patches in the final output
(e.g. "git log -p" or "git format-patch").  I think we _could_ cache the
result in-core if we wanted to, but that would require larger surgery to
the diffcore machinery (i.e. adding an extra pointer in the filepair
structure to keep a pointer to a strbuf around, stuff the textual diff to
the strbuf inside diffgrep_consume(), and make use of it in later stages
when it is available) and it may not be worth it.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 4656a97e6012796f182a725e14c13dc03f71bba2..f77a0f874937eb8e530d685fce2ee38e5e5f14a9 100644 (file)
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -284,8 +284,12 @@ ifndef::git-format-patch[]
        appearing in diff output; see the 'pickaxe' entry in
        linkgit:gitdiffcore[7] for more details.
 
+-G<regex>::
+       Look for differences whose added or removed line matches
+       the given <regex>.
+
 --pickaxe-all::
-       When `-S` finds a change, show all the changes in that
+       When `-S` or `-G` finds a change, show all the changes in that
        changeset, not just the files that contain the change
        in <string>.
 

diff --git a/diff.c b/diff.c
index 6631fa387cb716dc44834b04a2cf5bfd87226222..9095be16f6b556f587a610f07ca3cbe6b03a23a6 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -3268,12 +3268,17 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
        }
        else if ((argcount = short_opt('S', av, &optarg))) {
                options->pickaxe = optarg;
+               options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
+               return argcount;
+       } else if ((argcount = short_opt('G', av, &optarg))) {
+               options->pickaxe = optarg;
+               options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
                return argcount;
        }
        else if (!strcmp(arg, "--pickaxe-all"))
-               options->pickaxe_opts = DIFF_PICKAXE_ALL;
+               options->pickaxe_opts |= DIFF_PICKAXE_ALL;
        else if (!strcmp(arg, "--pickaxe-regex"))
-               options->pickaxe_opts = DIFF_PICKAXE_REGEX;
+               options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
        else if ((argcount = short_opt('O', av, &optarg))) {
                options->orderfile = optarg;
                return argcount;

diff --git a/diff.h b/diff.h
index bf2f44d840735684c89f654ee6f3b3a935af2c55..1fd44f5e47604b94c28a673e6cadc6ec870da9df 100644 (file)
--- a/diff.h
+++ b/diff.h
@@ -238,6 +238,9 @@ extern int diff_setup_done(struct diff_options *);
 #define DIFF_PICKAXE_ALL       1
 #define DIFF_PICKAXE_REGEX     2
 
+#define DIFF_PICKAXE_KIND_S    4 /* traditional plumbing counter */
+#define DIFF_PICKAXE_KIND_G    8 /* grep in the patch */
+
 extern void diffcore_std(struct diff_options *);
 extern void diffcore_fix_diff_index(struct diff_options *);
 

diff --git a/diffcore-pickaxe.c b/diffcore-pickaxe.c
index 13f61fbb083747adf41be8e01951c55055ee20c2..84195e47aa0a0e2fbeeb8a56d255ff5c6f42efe7 100644 (file)
--- a/diffcore-pickaxe.c
+++ b/diffcore-pickaxe.c
@@ -1,9 +1,148 @@
 /*
  * Copyright (C) 2005 Junio C Hamano
+ * Copyright (C) 2010 Google Inc.
  */
 #include "cache.h"
 #include "diff.h"
 #include "diffcore.h"
+#include "xdiff-interface.h"
+
+struct diffgrep_cb {
+       regex_t *regexp;
+       int hit;
+};
+
+static void diffgrep_consume(void *priv, char *line, unsigned long len)
+{
+       struct diffgrep_cb *data = priv;
+       regmatch_t regmatch;
+       int hold;
+
+       if (line[0] != '+' && line[0] != '-')
+               return;
+       if (data->hit)
+               /*
+                * NEEDSWORK: we should have a way to terminate the
+                * caller early.
+                */
+               return;
+       /* Yuck -- line ought to be "const char *"! */
+       hold = line[len];
+       line[len] = '\0';
+       data->hit = !regexec(data->regexp, line + 1, 1, &regmatch, 0);
+       line[len] = hold;
+}
+
+static void fill_one(struct diff_filespec *one,
+                    mmfile_t *mf, struct userdiff_driver **textconv)
+{
+       if (DIFF_FILE_VALID(one)) {
+               *textconv = get_textconv(one);
+               mf->size = fill_textconv(*textconv, one, &mf->ptr);
+       } else {
+               memset(mf, 0, sizeof(*mf));
+       }
+}
+
+static int diff_grep(struct diff_filepair *p, regex_t *regexp, struct diff_options *o)
+{
+       regmatch_t regmatch;
+       struct userdiff_driver *textconv_one = NULL;
+       struct userdiff_driver *textconv_two = NULL;
+       mmfile_t mf1, mf2;
+       int hit;
+
+       if (diff_unmodified_pair(p))
+               return 0;
+
+       fill_one(p->one, &mf1, &textconv_one);
+       fill_one(p->two, &mf2, &textconv_two);
+
+       if (!mf1.ptr) {
+               if (!mf2.ptr)
+                       return 0; /* ignore unmerged */
+               /* created "two" -- does it have what we are looking for? */
+               hit = !regexec(regexp, p->two->data, 1, &regmatch, 0);
+       } else if (!mf2.ptr) {
+               /* removed "one" -- did it have what we are looking for? */
+               hit = !regexec(regexp, p->one->data, 1, &regmatch, 0);
+       } else {
+               /*
+                * We have both sides; need to run textual diff and see if
+                * the pattern appears on added/deleted lines.
+                */
+               struct diffgrep_cb ecbdata;
+               xpparam_t xpp;
+               xdemitconf_t xecfg;
+
+               memset(&xpp, 0, sizeof(xpp));
+               memset(&xecfg, 0, sizeof(xecfg));
+               ecbdata.regexp = regexp;
+               ecbdata.hit = 0;
+               xecfg.ctxlen = o->context;
+               xecfg.interhunkctxlen = o->interhunkcontext;
+               xdi_diff_outf(&mf1, &mf2, diffgrep_consume, &ecbdata,
+                             &xpp, &xecfg);
+               hit = ecbdata.hit;
+       }
+       if (textconv_one)
+               free(mf1.ptr);
+       if (textconv_two)
+               free(mf2.ptr);
+       return hit;
+}
+
+static void diffcore_pickaxe_grep(struct diff_options *o)
+{
+       struct diff_queue_struct *q = &diff_queued_diff;
+       int i, has_changes, err;
+       regex_t regex;
+       struct diff_queue_struct outq;
+       outq.queue = NULL;
+       outq.nr = outq.alloc = 0;
+
+       err = regcomp(&regex, o->pickaxe, REG_EXTENDED | REG_NEWLINE);
+       if (err) {
+               char errbuf[1024];
+               regerror(err, &regex, errbuf, 1024);
+               regfree(&regex);
+               die("invalid log-grep regex: %s", errbuf);
+       }
+
+       if (o->pickaxe_opts & DIFF_PICKAXE_ALL) {
+               /* Showing the whole changeset if needle exists */
+               for (i = has_changes = 0; !has_changes && i < q->nr; i++) {
+                       struct diff_filepair *p = q->queue[i];
+                       if (diff_grep(p, &regex, o))
+                               has_changes++;
+               }
+               if (has_changes)
+                       return; /* do not munge the queue */
+
+               /*
+                * Otherwise we will clear the whole queue by copying
+                * the empty outq at the end of this function, but
+                * first clear the current entries in the queue.
+                */
+               for (i = 0; i < q->nr; i++)
+                       diff_free_filepair(q->queue[i]);
+       } else {
+               /* Showing only the filepairs that has the needle */
+               for (i = 0; i < q->nr; i++) {
+                       struct diff_filepair *p = q->queue[i];
+                       if (diff_grep(p, &regex, o))
+                               diff_q(&outq, p);
+                       else
+                               diff_free_filepair(p);
+               }
+       }
+
+       regfree(&regex);
+
+       free(q->queue);
+       *q = outq;
+       return;
+}
 
 static unsigned int contains(struct diff_filespec *one,
                             const char *needle, unsigned long len,
@@ -48,7 +187,7 @@ static unsigned int contains(struct diff_filespec *one,
        return cnt;
 }
 
-void diffcore_pickaxe(struct diff_options *o)
+static void diffcore_pickaxe_count(struct diff_options *o)
 {
        const char *needle = o->pickaxe;
        int opts = o->pickaxe_opts;
@@ -138,3 +277,12 @@ void diffcore_pickaxe(struct diff_options *o)
        *q = outq;
        return;
 }
+
+void diffcore_pickaxe(struct diff_options *o)
+{
+       /* Might want to warn when both S and G are on; I don't care... */
+       if (o->pickaxe_opts & DIFF_PICKAXE_KIND_G)
+               return diffcore_pickaxe_grep(o);
+       else
+               return diffcore_pickaxe_count(o);
+}