combine-diff: use built-in xdiff.
[git.git] / combine-diff.c
index 7693884..11f5143 100644 (file)
@@ -4,6 +4,7 @@
 #include "diff.h"
 #include "diffcore.h"
 #include "quote.h"
+#include "xdiff/xdiff.h"
 
 static int uninteresting(struct diff_filepair *p)
 {
@@ -110,28 +111,6 @@ static char *grab_blob(const unsigned char *sha1, unsigned long *size)
        return blob;
 }
 
-#define TMPPATHLEN 50
-#define MAXLINELEN 10240
-
-static void write_to_temp_file(char *tmpfile, void *blob, unsigned long size)
-{
-       int fd = git_mkstemp(tmpfile, TMPPATHLEN, ".diff_XXXXXX");
-       if (fd < 0)
-               die("unable to create temp-file");
-       if (write(fd, blob, size) != size)
-               die("unable to write temp-file");
-       close(fd);
-}
-
-static void write_temp_blob(char *tmpfile, const unsigned char *sha1)
-{
-       unsigned long size;
-       void *blob;
-       blob = grab_blob(sha1, &size);
-       write_to_temp_file(tmpfile, blob, size);
-       free(blob);
-}
-
 static int parse_num(char **cp_p, unsigned int *num_p)
 {
        char *cp = *cp_p;
@@ -178,10 +157,9 @@ static int parse_hunk_header(char *line, int len,
        return -!!memcmp(cp, " @@", 3);
 }
 
-static void append_lost(struct sline *sline, int n, const char *line)
+static void append_lost(struct sline *sline, int n, const char *line, int len)
 {
        struct lline *lline;
-       int len = strlen(line);
        unsigned long this_mask = (1UL<<n);
        if (line[len-1] == '\n')
                len--;
@@ -216,70 +194,130 @@ static void append_lost(struct sline *sline, int n, const char *line)
        sline->lost_tail = &lline->next;
 }
 
-static void combine_diff(const unsigned char *parent, const char *ourtmp,
+struct combine_diff_state {
+       char *remainder;
+       unsigned long remainder_size;
+       unsigned int lno, ob, on, nb, nn;
+       unsigned long nmask;
+       int num_parent;
+       int n;
+       struct sline *sline;
+       struct sline *lost_bucket;
+};
+
+static void consume_line(struct combine_diff_state *state,
+                        char *line,
+                        unsigned long len)
+{
+       if (5 < len && !memcmp("@@ -", line, 4)) {
+               if (parse_hunk_header(line, len,
+                                     &state->ob, &state->on,
+                                     &state->nb, &state->nn))
+                       return;
+               state->lno = state->nb;
+               if (!state->nb)
+                       /* @@ -1,2 +0,0 @@ to remove the
+                        * first two lines...
+                        */
+                       state->nb = 1;
+               if (state->nn == 0)
+                       /* @@ -X,Y +N,0 @@ removed Y lines
+                        * that would have come *after* line N
+                        * in the result.  Our lost buckets hang
+                        * to the line after the removed lines,
+                        */
+                       state->lost_bucket = &state->sline[state->nb];
+               else
+                       state->lost_bucket = &state->sline[state->nb-1];
+               if (!state->sline[state->nb-1].p_lno)
+                       state->sline[state->nb-1].p_lno =
+                               xcalloc(state->num_parent,
+                                       sizeof(unsigned long));
+               state->sline[state->nb-1].p_lno[state->n] = state->ob;
+               return;
+       }
+       if (!state->lost_bucket)
+               return; /* not in any hunk yet */
+       switch (line[0]) {
+       case '-':
+               append_lost(state->lost_bucket, state->n, line+1, len-1);
+               break;
+       case '+':
+               state->sline[state->lno-1].flag |= state->nmask;
+               state->lno++;
+               break;
+       }
+}
+
+static int combine_diff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
+{
+       struct combine_diff_state *priv = priv_;
+       int i;
+       for (i = 0; i < nbuf; i++) {
+               if (mb[i].ptr[mb[i].size-1] != '\n') {
+                       /* Incomplete line */
+                       priv->remainder = realloc(priv->remainder,
+                                                 priv->remainder_size +
+                                                 mb[i].size);
+                       memcpy(priv->remainder + priv->remainder_size,
+                              mb[i].ptr, mb[i].size);
+                       priv->remainder_size += mb[i].size;
+                       continue;
+               }
+
+               /* we have a complete line */
+               if (!priv->remainder) {
+                       consume_line(priv, mb[i].ptr, mb[i].size);
+                       continue;
+               }
+               priv->remainder = realloc(priv->remainder,
+                                         priv->remainder_size +
+                                         mb[i].size);
+               memcpy(priv->remainder + priv->remainder_size,
+                      mb[i].ptr, mb[i].size);
+               consume_line(priv, priv->remainder,
+                            priv->remainder_size + mb[i].size);
+               free(priv->remainder);
+               priv->remainder = NULL;
+               priv->remainder_size = 0;
+       }
+       return 0;
+}
+
+static void combine_diff(const unsigned char *parent, mmfile_t *result_file,
                         struct sline *sline, int cnt, int n, int num_parent)
 {
-       FILE *in;
-       char parent_tmp[TMPPATHLEN];
-       char cmd[TMPPATHLEN * 2 + 1024];
-       char line[MAXLINELEN];
-       unsigned int lno, ob, on, nb, nn, p_lno;
+       unsigned int p_lno, lno;
        unsigned long nmask = (1UL << n);
-       struct sline *lost_bucket = NULL;
+       xpparam_t xpp;
+       xdemitconf_t xecfg;
+       mmfile_t parent_file;
+       xdemitcb_t ecb;
+       struct combine_diff_state state;
+       unsigned long sz;
 
        if (!cnt)
                return; /* result deleted */
 
-       write_temp_blob(parent_tmp, parent);
-       sprintf(cmd, "diff --unified=0 -La/x -Lb/x '%s' '%s'",
-               parent_tmp, ourtmp);
-       in = popen(cmd, "r");
-       if (!in)
-               die("cannot spawn %s", cmd);
-
-       lno = 1;
-       while (fgets(line, sizeof(line), in) != NULL) {
-               int len = strlen(line);
-               if (5 < len && !memcmp("@@ -", line, 4)) {
-                       if (parse_hunk_header(line, len,
-                                             &ob, &on, &nb, &nn))
-                               break;
-                       lno = nb;
-                       if (!nb)
-                               /* @@ -1,2 +0,0 @@ to remove the
-                                * first two lines...
-                                */
-                               nb = 1;
-                       if (nn == 0)
-                               /* @@ -X,Y +N,0 @@ removed Y lines
-                                * that would have come *after* line N
-                                * in the result.  Our lost buckets hang
-                                * to the line after the removed lines,
-                                */
-                               lost_bucket = &sline[nb];
-                       else
-                               lost_bucket = &sline[nb-1];
-                       if (!sline[nb-1].p_lno)
-                               sline[nb-1].p_lno =
-                                       xcalloc(num_parent,
-                                               sizeof(unsigned long));
-                       sline[nb-1].p_lno[n] = ob;
-                       continue;
-               }
-               if (!lost_bucket)
-                       continue; /* not in any hunk yet */
-               switch (line[0]) {
-               case '-':
-                       append_lost(lost_bucket, n, line+1);
-                       break;
-               case '+':
-                       sline[lno-1].flag |= nmask;
-                       lno++;
-                       break;
-               }
-       }
-       fclose(in);
-       unlink(parent_tmp);
+       parent_file.ptr = grab_blob(parent, &sz);
+       parent_file.size = sz;
+       xpp.flags = XDF_NEED_MINIMAL;
+       xecfg.ctxlen = 0;
+       xecfg.flags = 0;
+       ecb.outf = combine_diff_outf;
+       ecb.priv = &state;
+       memset(&state, 0, sizeof(state));
+       state.nmask = nmask;
+       state.sline = sline;
+       state.lno = 1;
+       state.num_parent = num_parent;
+       state.n = n;
+
+       xdl_diff(&parent_file, result_file, &xpp, &xecfg, &ecb);
+       if (state.remainder && state.remainder_size)
+               consume_line(&state, state.remainder, state.remainder_size);
+       free(state.remainder);
+       free(parent_file.ptr);
 
        /* Assign line numbers for this parent.
         *
@@ -625,61 +663,56 @@ static int show_patch_diff(struct combine_diff_path *elem, int num_parent,
                           int dense, const char *header,
                           struct diff_options *opt)
 {
-       unsigned long size, cnt, lno;
+       unsigned long result_size, cnt, lno;
        char *result, *cp, *ep;
        struct sline *sline; /* survived lines */
        int mode_differs = 0;
        int i, show_hunks, shown_header = 0;
-       char ourtmp_buf[TMPPATHLEN];
-       char *ourtmp = ourtmp_buf;
        int working_tree_file = !memcmp(elem->sha1, null_sha1, 20);
        int abbrev = opt->full_index ? 40 : DEFAULT_ABBREV;
+       mmfile_t result_file;
 
        /* Read the result of merge first */
-       if (!working_tree_file) {
-               result = grab_blob(elem->sha1, &size);
-               write_to_temp_file(ourtmp, result, size);
-       }
+       if (!working_tree_file)
+               result = grab_blob(elem->sha1, &result_size);
        else {
                /* Used by diff-tree to read from the working tree */
                struct stat st;
                int fd;
-               ourtmp = elem->path;
-               if (0 <= (fd = open(ourtmp, O_RDONLY)) &&
+               if (0 <= (fd = open(elem->path, O_RDONLY)) &&
                    !fstat(fd, &st)) {
                        int len = st.st_size;
                        int cnt = 0;
 
                        elem->mode = canon_mode(st.st_mode);
-                       size = len;
+                       result_size = len;
                        result = xmalloc(len + 1);
                        while (cnt < len) {
                                int done = xread(fd, result+cnt, len-cnt);
                                if (done == 0)
                                        break;
                                if (done < 0)
-                                       die("read error '%s'", ourtmp);
+                                       die("read error '%s'", elem->path);
                                cnt += done;
                        }
                        result[len] = 0;
                }
                else {
                        /* deleted file */
-                       size = 0;
+                       result_size = 0;
                        elem->mode = 0;
                        result = xmalloc(1);
                        result[0] = 0;
-                       ourtmp = "/dev/null";
                }
                if (0 <= fd)
                        close(fd);
        }
 
-       for (cnt = 0, cp = result; cp - result < size; cp++) {
+       for (cnt = 0, cp = result; cp - result < result_size; cp++) {
                if (*cp == '\n')
                        cnt++;
        }
-       if (size && result[size-1] != '\n')
+       if (result_size && result[result_size-1] != '\n')
                cnt++; /* incomplete line */
 
        sline = xcalloc(cnt+1, sizeof(*sline));
@@ -689,7 +722,7 @@ static int show_patch_diff(struct combine_diff_path *elem, int num_parent,
                sline[lno].lost_tail = &sline[lno].lost_head;
                sline[lno].flag = 0;
        }
-       for (lno = 0, cp = result; cp - result < size; cp++) {
+       for (lno = 0, cp = result; cp - result < result_size; cp++) {
                if (*cp == '\n') {
                        sline[lno].len = cp - sline[lno].bol;
                        lno++;
@@ -697,8 +730,11 @@ static int show_patch_diff(struct combine_diff_path *elem, int num_parent,
                                sline[lno].bol = cp + 1;
                }
        }
-       if (size && result[size-1] != '\n')
-               sline[cnt-1].len = size - (sline[cnt-1].bol - result);
+       if (result_size && result[result_size-1] != '\n')
+               sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
+
+       result_file.ptr = result;
+       result_file.size = result_size;
 
        sline[0].p_lno = xcalloc((cnt+1) * num_parent, sizeof(unsigned long));
        for (lno = 0; lno < cnt; lno++)
@@ -714,7 +750,7 @@ static int show_patch_diff(struct combine_diff_path *elem, int num_parent,
                        }
                }
                if (i <= j)
-                       combine_diff(elem->parent[i].sha1, ourtmp, sline,
+                       combine_diff(elem->parent[i].sha1, &result_file, sline,
                                     cnt, i, num_parent);
                if (elem->parent[i].mode != elem->mode)
                        mode_differs = 1;
@@ -767,8 +803,6 @@ static int show_patch_diff(struct combine_diff_path *elem, int num_parent,
                }
                dump_sline(sline, cnt, num_parent);
        }
-       if (ourtmp == ourtmp_buf)
-               unlink(ourtmp);
        free(result);
 
        for (i = 0; i < cnt; i++) {