Merge branch 'jc/diff-mark'
authorJunio C Hamano <gitster@pobox.com>
Sat, 7 Jul 2007 20:37:32 +0000 (13:37 -0700)
committerJunio C Hamano <gitster@pobox.com>
Sat, 7 Jul 2007 20:37:32 +0000 (13:37 -0700)
* jc/diff-mark:
  diff: honor binariness specified in attributes
  Fix configuration syntax to specify customized hunk header patterns.
  Per-path attribute based hunk header selection.
  Future-proof source for changes in xdemitconf_t
  Introduce diff_filespec_is_binary()

14 files changed:
builtin-blame.c
builtin-rerere.c
combine-diff.c
diff.c
diffcore-delta.c
diffcore.h
merge-file.c
merge-tree.c
t/t4018-diff-funcname.sh [new file with mode: 0644]
t/t4020-diff-external.sh
xdiff-interface.c
xdiff-interface.h
xdiff/xdiff.h
xdiff/xemit.c

index da23a6f..0519339 100644 (file)
@@ -518,8 +518,8 @@ static struct patch *compare_buffer(mmfile_t *file_p, mmfile_t *file_o,
        xdemitcb_t ecb;
 
        xpp.flags = xdl_opts;
+       memset(&xecfg, 0, sizeof(xecfg));
        xecfg.ctxlen = context;
-       xecfg.flags = 0;
        ecb.outf = xdiff_outf;
        ecb.priv = &state;
        memset(&state, 0, sizeof(state));
index 3196151..c25b3d5 100644 (file)
@@ -285,8 +285,8 @@ static int diff_two(const char *file1, const char *label1,
        printf("--- a/%s\n+++ b/%s\n", label1, label2);
        fflush(stdout);
        xpp.flags = XDF_NEED_MINIMAL;
+       memset(&xecfg, 0, sizeof(xecfg));
        xecfg.ctxlen = 3;
-       xecfg.flags = 0;
        ecb.outf = outf;
        xdl_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 
index ea3ca5f..ef62234 100644 (file)
@@ -215,8 +215,7 @@ static void combine_diff(const unsigned char *parent, mmfile_t *result_file,
        parent_file.ptr = grab_blob(parent, &sz);
        parent_file.size = sz;
        xpp.flags = XDF_NEED_MINIMAL;
-       xecfg.ctxlen = 0;
-       xecfg.flags = 0;
+       memset(&xecfg, 0, sizeof(xecfg));
        ecb.outf = xdiff_outf;
        ecb.priv = &state;
        memset(&state, 0, sizeof(state));
diff --git a/diff.c b/diff.c
index 1958970..b8473f5 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -56,6 +56,14 @@ static struct ll_diff_driver {
        char *cmd;
 } *user_diff, **user_diff_tail;
 
+static void read_config_if_needed(void)
+{
+       if (!user_diff_tail) {
+               user_diff_tail = &user_diff;
+               git_config(git_diff_ui_config);
+       }
+}
+
 /*
  * Currently there is only "diff.<drivername>.command" variable;
  * because there are "diff.color.<slot>" variables, we are parsing
@@ -93,6 +101,45 @@ static int parse_lldiff_command(const char *var, const char *ep, const char *val
        return 0;
 }
 
+/*
+ * 'diff.<what>.funcname' attribute can be specified in the configuration
+ * to define a customized regexp to find the beginning of a function to
+ * be used for hunk header lines of "diff -p" style output.
+ */
+static struct funcname_pattern {
+       char *name;
+       char *pattern;
+       struct funcname_pattern *next;
+} *funcname_pattern_list;
+
+static int parse_funcname_pattern(const char *var, const char *ep, const char *value)
+{
+       const char *name;
+       int namelen;
+       struct funcname_pattern *pp;
+
+       name = var + 5; /* "diff." */
+       namelen = ep - name;
+
+       for (pp = funcname_pattern_list; pp; pp = pp->next)
+               if (!strncmp(pp->name, name, namelen) && !pp->name[namelen])
+                       break;
+       if (!pp) {
+               char *namebuf;
+               pp = xcalloc(1, sizeof(*pp));
+               namebuf = xmalloc(namelen + 1);
+               memcpy(namebuf, name, namelen);
+               namebuf[namelen] = 0;
+               pp->name = namebuf;
+               pp->next = funcname_pattern_list;
+               funcname_pattern_list = pp;
+       }
+       if (pp->pattern)
+               free(pp->pattern);
+       pp->pattern = xstrdup(value);
+       return 0;
+}
+
 /*
  * These are to give UI layer defaults.
  * The core-level commands such as git-diff-files should
@@ -122,8 +169,12 @@ int git_diff_ui_config(const char *var, const char *value)
        if (!prefixcmp(var, "diff.")) {
                const char *ep = strrchr(var, '.');
 
-               if (ep != var + 4 && !strcmp(ep, ".command"))
-                       return parse_lldiff_command(var, ep, value);
+               if (ep != var + 4) {
+                       if (!strcmp(ep, ".command"))
+                               return parse_lldiff_command(var, ep, value);
+                       if (!strcmp(ep, ".funcname"))
+                               return parse_funcname_pattern(var, ep, value);
+               }
        }
        if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
                int slot = parse_diff_color_slot(var, 11);
@@ -390,6 +441,7 @@ static void diff_words_show(struct diff_words_data *diff_words)
        mmfile_t minus, plus;
        int i;
 
+       memset(&xecfg, 0, sizeof(xecfg));
        minus.size = diff_words->minus.text.size;
        minus.ptr = xmalloc(minus.size);
        memcpy(minus.ptr, diff_words->minus.text.ptr, minus.size);
@@ -408,7 +460,6 @@ static void diff_words_show(struct diff_words_data *diff_words)
 
        xpp.flags = XDF_NEED_MINIMAL;
        xecfg.ctxlen = diff_words->minus.alloc + diff_words->plus.alloc;
-       xecfg.flags = 0;
        ecb.outf = xdiff_outf;
        ecb.priv = diff_words;
        diff_words->xm.consume = fn_out_diff_words_aux;
@@ -1102,30 +1153,101 @@ static void setup_diff_attr_check(struct git_attr_check *check)
 {
        static struct git_attr *attr_diff;
 
-       if (!attr_diff)
+       if (!attr_diff) {
                attr_diff = git_attr("diff", 4);
-       check->attr = attr_diff;
+       }
+       check[0].attr = attr_diff;
 }
 
-static int file_is_binary(struct diff_filespec *one)
+static void diff_filespec_check_attr(struct diff_filespec *one)
 {
        struct git_attr_check attr_diff_check;
+       int check_from_data = 0;
+
+       if (one->checked_attr)
+               return;
 
        setup_diff_attr_check(&attr_diff_check);
+       one->is_binary = 0;
+       one->funcname_pattern_ident = NULL;
+
        if (!git_checkattr(one->path, 1, &attr_diff_check)) {
-               const char *value = attr_diff_check.value;
+               const char *value;
+
+               /* binaryness */
+               value = attr_diff_check.value;
                if (ATTR_TRUE(value))
-                       return 0;
+                       ;
                else if (ATTR_FALSE(value))
-                       return 1;
+                       one->is_binary = 1;
+               else
+                       check_from_data = 1;
+
+               /* funcname pattern ident */
+               if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
+                       ;
+               else
+                       one->funcname_pattern_ident = value;
        }
 
-       if (!one->data) {
-               if (!DIFF_FILE_VALID(one))
-                       return 0;
-               diff_populate_filespec(one, 0);
+       if (check_from_data) {
+               if (!one->data && DIFF_FILE_VALID(one))
+                       diff_populate_filespec(one, 0);
+
+               if (one->data)
+                       one->is_binary = buffer_is_binary(one->data, one->size);
        }
-       return buffer_is_binary(one->data, one->size);
+}
+
+int diff_filespec_is_binary(struct diff_filespec *one)
+{
+       diff_filespec_check_attr(one);
+       return one->is_binary;
+}
+
+static const char *funcname_pattern(const char *ident)
+{
+       struct funcname_pattern *pp;
+
+       read_config_if_needed();
+       for (pp = funcname_pattern_list; pp; pp = pp->next)
+               if (!strcmp(ident, pp->name))
+                       return pp->pattern;
+       return NULL;
+}
+
+static const char *diff_funcname_pattern(struct diff_filespec *one)
+{
+       const char *ident, *pattern;
+
+       diff_filespec_check_attr(one);
+       ident = one->funcname_pattern_ident;
+
+       if (!ident)
+               /*
+                * If the config file has "funcname.default" defined, that
+                * regexp is used; otherwise NULL is returned and xemit uses
+                * the built-in default.
+                */
+               return funcname_pattern("default");
+
+       /* Look up custom "funcname.$ident" regexp from config. */
+       pattern = funcname_pattern(ident);
+       if (pattern)
+               return pattern;
+
+       /*
+        * And define built-in fallback patterns here.  Note that
+        * these can be overriden by the user's config settings.
+        */
+       if (!strcmp(ident, "java"))
+               return "!^[     ]*\\(catch\\|do\\|for\\|if\\|instanceof\\|"
+                       "new\\|return\\|switch\\|throw\\|while\\)\n"
+                       "^[     ]*\\(\\([       ]*"
+                       "[A-Za-z_][A-Za-z_0-9]*\\)\\{2,\\}"
+                       "[      ]*([^;]*$\\)";
+
+       return NULL;
 }
 
 static void builtin_diff(const char *name_a,
@@ -1182,7 +1304,8 @@ static void builtin_diff(const char *name_a,
        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
                die("unable to read files to diff");
 
-       if (!o->text && (file_is_binary(one) || file_is_binary(two))) {
+       if (!o->text &&
+           (diff_filespec_is_binary(one) || diff_filespec_is_binary(two))) {
                /* Quite common confusing case */
                if (mf1.size == mf2.size &&
                    !memcmp(mf1.ptr, mf2.ptr, mf1.size))
@@ -1201,7 +1324,13 @@ static void builtin_diff(const char *name_a,
                xdemitconf_t xecfg;
                xdemitcb_t ecb;
                struct emit_callback ecbdata;
+               const char *funcname_pattern;
 
+               funcname_pattern = diff_funcname_pattern(one);
+               if (!funcname_pattern)
+                       funcname_pattern = diff_funcname_pattern(two);
+
+               memset(&xecfg, 0, sizeof(xecfg));
                memset(&ecbdata, 0, sizeof(ecbdata));
                ecbdata.label_path = lbl;
                ecbdata.color_diff = o->color_diff;
@@ -1209,6 +1338,8 @@ static void builtin_diff(const char *name_a,
                xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
                xecfg.ctxlen = o->context;
                xecfg.flags = XDL_EMIT_FUNCNAMES;
+               if (funcname_pattern)
+                       xdiff_set_find_func(&xecfg, funcname_pattern);
                if (!diffopts)
                        ;
                else if (!prefixcmp(diffopts, "--unified="))
@@ -1260,7 +1391,7 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
                die("unable to read files to diff");
 
-       if (file_is_binary(one) || file_is_binary(two)) {
+       if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
                data->is_binary = 1;
                data->added = mf2.size;
                data->deleted = mf1.size;
@@ -1270,9 +1401,8 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
                xdemitconf_t xecfg;
                xdemitcb_t ecb;
 
+               memset(&xecfg, 0, sizeof(xecfg));
                xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
-               xecfg.ctxlen = 0;
-               xecfg.flags = 0;
                ecb.outf = xdiff_outf;
                ecb.priv = diffstat;
                xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
@@ -1302,7 +1432,7 @@ static void builtin_checkdiff(const char *name_a, const char *name_b,
        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
                die("unable to read files to diff");
 
-       if (file_is_binary(two))
+       if (diff_filespec_is_binary(two))
                goto free_and_return;
        else {
                /* Crazy xdl interfaces.. */
@@ -1310,9 +1440,8 @@ static void builtin_checkdiff(const char *name_a, const char *name_b,
                xdemitconf_t xecfg;
                xdemitcb_t ecb;
 
+               memset(&xecfg, 0, sizeof(xecfg));
                xpp.flags = XDF_NEED_MINIMAL;
-               xecfg.ctxlen = 0;
-               xecfg.flags = 0;
                ecb.outf = xdiff_outf;
                ecb.priv = &data;
                xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
@@ -1753,10 +1882,7 @@ static const char *external_diff_attr(const char *name)
                    !ATTR_UNSET(value)) {
                        struct ll_diff_driver *drv;
 
-                       if (!user_diff_tail) {
-                               user_diff_tail = &user_diff;
-                               git_config(git_diff_ui_config);
-                       }
+                       read_config_if_needed();
                        for (drv = user_diff; drv; drv = drv->next)
                                if (!strcmp(drv->name, value))
                                        return drv->cmd;
@@ -1880,8 +2006,8 @@ static void run_diff(struct diff_filepair *p, struct diff_options *o)
 
                if (o->binary) {
                        mmfile_t mf;
-                       if ((!fill_mmfile(&mf, one) && file_is_binary(one)) ||
-                           (!fill_mmfile(&mf, two) && file_is_binary(two)))
+                       if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
+                           (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
                                abbrev = 40;
                }
                len += snprintf(msg + len, sizeof(msg) - len,
@@ -2764,6 +2890,7 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
                struct diff_filepair *p = q->queue[i];
                int len1, len2;
 
+               memset(&xecfg, 0, sizeof(xecfg));
                if (p->status == 0)
                        return error("internal diff status error");
                if (p->status == DIFF_STATUS_UNKNOWN)
@@ -2783,7 +2910,7 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
                        return error("unable to read files to diff");
 
                /* Maybe hash p->two? into the patch id? */
-               if (file_is_binary(p->two))
+               if (diff_filespec_is_binary(p->two))
                        continue;
 
                len1 = remove_space(p->one->path, strlen(p->one->path));
@@ -3011,21 +3138,6 @@ void diffcore_std(struct diff_options *options)
        if (options->quiet)
                return;
 
-       /*
-        * break/rename count similarity differently depending on
-        * the binary-ness.
-        */
-       if ((options->break_opt != -1) || (options->detect_rename)) {
-               struct diff_queue_struct *q = &diff_queued_diff;
-               int i;
-
-               for (i = 0; i < q->nr; i++) {
-                       struct diff_filepair *p = q->queue[i];
-                       p->one->is_binary = file_is_binary(p->one);
-                       p->two->is_binary = file_is_binary(p->two);
-               }
-       }
-
        if (options->break_opt != -1)
                diffcore_break(options->break_opt);
        if (options->detect_rename)
index a038b16..d9729e5 100644 (file)
@@ -129,7 +129,7 @@ static struct spanhash_top *hash_chars(struct diff_filespec *one)
        struct spanhash_top *hash;
        unsigned char *buf = one->data;
        unsigned int sz = one->size;
-       int is_text = !one->is_binary;
+       int is_text = !diff_filespec_is_binary(one);
 
        i = INITIAL_HASH_SIZE;
        hash = xmalloc(sizeof(*hash) + sizeof(struct spanhash) * (1<<i));
index 0c8abb5..eef17c4 100644 (file)
@@ -27,6 +27,7 @@ struct diff_filespec {
        char *path;
        void *data;
        void *cnt_data;
+       const char *funcname_pattern_ident;
        unsigned long size;
        int xfrm_flags;          /* for use by the xfrm */
        unsigned short mode;     /* file mode */
@@ -37,6 +38,7 @@ struct diff_filespec {
 #define DIFF_FILE_VALID(spec) (((spec)->mode) != 0)
        unsigned should_free : 1; /* data should be free()'ed */
        unsigned should_munmap : 1; /* data should be munmap()'ed */
+       unsigned checked_attr : 1;
        unsigned is_binary : 1; /* data should be considered "binary" */
 };
 
@@ -46,6 +48,7 @@ extern void fill_filespec(struct diff_filespec *, const unsigned char *,
 
 extern int diff_populate_filespec(struct diff_filespec *, int);
 extern void diff_free_filespec_data(struct diff_filespec *);
+extern int diff_filespec_is_binary(struct diff_filespec *);
 
 struct diff_filepair {
        struct diff_filespec *one;
index 748d15c..1e031ea 100644 (file)
@@ -62,6 +62,7 @@ static int generate_common_file(mmfile_t *res, mmfile_t *f1, mmfile_t *f2)
        xdemitcb_t ecb;
 
        xpp.flags = XDF_NEED_MINIMAL;
+       memset(&xecfg, 0, sizeof(xecfg));
        xecfg.ctxlen = 3;
        xecfg.flags = XDL_EMIT_COMMON;
        ecb.outf = common_outf;
index 3b8d9e6..7d4f628 100644 (file)
@@ -106,8 +106,8 @@ static void show_diff(struct merge_list *entry)
        xdemitcb_t ecb;
 
        xpp.flags = XDF_NEED_MINIMAL;
+       memset(&xecfg, 0, sizeof(xecfg));
        xecfg.ctxlen = 3;
-       xecfg.flags = 0;
        ecb.outf = show_outf;
        ecb.priv = NULL;
 
diff --git a/t/t4018-diff-funcname.sh b/t/t4018-diff-funcname.sh
new file mode 100644 (file)
index 0000000..f9db81d
--- /dev/null
@@ -0,0 +1,60 @@
+#!/bin/sh
+#
+# Copyright (c) 2007 Johannes E. Schindelin
+#
+
+test_description='Test custom diff function name patterns'
+
+. ./test-lib.sh
+
+LF='
+'
+
+cat > Beer.java << EOF
+public class Beer
+{
+       int special;
+       public static void main(String args[])
+       {
+               String s=" ";
+               for(int x = 99; x > 0; x--)
+               {
+                       System.out.print(x + " bottles of beer on the wall "
+                               + x + " bottles of beer\n"
+                               + "Take one down, pass it around, " + (x - 1)
+                               + " bottles of beer on the wall.\n");
+               }
+               System.out.print("Go to the store, buy some more,\n"
+                       + "99 bottles of beer on the wall.\n");
+       }
+}
+EOF
+
+sed 's/beer\\/beer,\\/' < Beer.java > Beer-correct.java
+
+test_expect_success 'default behaviour' '
+       git diff Beer.java Beer-correct.java |
+       grep "^@@.*@@ public class Beer"
+'
+
+test_expect_success 'preset java pattern' '
+       echo "*.java diff=java" >.gitattributes &&
+       git diff Beer.java Beer-correct.java |
+       grep "^@@.*@@ public static void main("
+'
+
+git config diff.java.funcname '!static
+!String
+[^     ].*s.*'
+
+test_expect_success 'custom pattern' '
+       git diff Beer.java Beer-correct.java |
+       grep "^@@.*@@ int special;$"
+'
+
+test_expect_success 'last regexp must not be negated' '
+       git config diff.java.funcname "!static" &&
+       ! git diff Beer.java Beer-correct.java
+'
+
+test_done
index f0045cd..ed3bd5b 100755 (executable)
@@ -94,4 +94,16 @@ test_expect_success 'diff attribute should apply only to diff' '
 
 '
 
+test_expect_success 'no diff with -diff' '
+       echo >.gitattributes "file -diff" &&
+       git diff | grep Binary
+'
+
+echo NULZbetweenZwords | tr Z '\0' > file
+
+test_expect_success 'force diff with "diff"' '
+       echo >.gitattributes "file diff" &&
+       git diff | grep -a second
+'
+
 test_done
index e407cf1..be866d1 100644 (file)
@@ -129,3 +129,74 @@ int buffer_is_binary(const char *ptr, unsigned long size)
                size = FIRST_FEW_BYTES;
        return !!memchr(ptr, 0, size);
 }
+
+struct ff_regs {
+       int nr;
+       struct ff_reg {
+               regex_t re;
+               int negate;
+       } *array;
+};
+
+static long ff_regexp(const char *line, long len,
+               char *buffer, long buffer_size, void *priv)
+{
+       char *line_buffer = xstrndup(line, len); /* make NUL terminated */
+       struct ff_regs *regs = priv;
+       regmatch_t pmatch[2];
+       int result = 0, i;
+
+       for (i = 0; i < regs->nr; i++) {
+               struct ff_reg *reg = regs->array + i;
+               if (reg->negate ^ !!regexec(&reg->re,
+                                       line_buffer, 2, pmatch, 0)) {
+                       free(line_buffer);
+                       return -1;
+               }
+       }
+       i = pmatch[1].rm_so >= 0 ? 1 : 0;
+       line += pmatch[i].rm_so;
+       result = pmatch[i].rm_eo - pmatch[i].rm_so;
+       if (result > buffer_size)
+               result = buffer_size;
+       else
+               while (result > 0 && (isspace(line[result - 1]) ||
+                                       line[result - 1] == '\n'))
+                       result--;
+       memcpy(buffer, line, result);
+       free(line_buffer);
+       return result;
+}
+
+void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value)
+{
+       int i;
+       struct ff_regs *regs;
+
+       xecfg->find_func = ff_regexp;
+       regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
+       for (i = 0, regs->nr = 1; value[i]; i++)
+               if (value[i] == '\n')
+                       regs->nr++;
+       regs->array = xmalloc(regs->nr * sizeof(struct ff_reg));
+       for (i = 0; i < regs->nr; i++) {
+               struct ff_reg *reg = regs->array + i;
+               const char *ep = strchr(value, '\n'), *expression;
+               char *buffer = NULL;
+
+               reg->negate = (*value == '!');
+               if (reg->negate && i == regs->nr - 1)
+                       die("Last expression must not be negated: %s", value);
+               if (*value == '!')
+                       value++;
+               if (ep)
+                       expression = buffer = xstrndup(value, ep - value);
+               else
+                       expression = value;
+               if (regcomp(&reg->re, expression, 0))
+                       die("Invalid regexp to look for hunk header: %s", expression);
+               if (buffer)
+                       free(buffer);
+               value = ep + 1;
+       }
+}
index 536f4e4..fb742db 100644 (file)
@@ -20,4 +20,6 @@ int parse_hunk_header(char *line, int len,
 int read_mmfile(mmfile_t *ptr, const char *filename);
 int buffer_is_binary(const char *ptr, unsigned long size);
 
+extern void xdiff_set_find_func(xdemitconf_t *xecfg, const char *line);
+
 #endif
index 9402bb0..c00ddaa 100644 (file)
@@ -73,9 +73,13 @@ typedef struct s_xdemitcb {
        int (*outf)(void *, mmbuffer_t *, int);
 } xdemitcb_t;
 
+typedef long (*find_func_t)(const char *line, long line_len, char *buffer, long buffer_size, void *priv);
+
 typedef struct s_xdemitconf {
        long ctxlen;
        unsigned long flags;
+       find_func_t find_func;
+       void *find_func_priv;
 } xdemitconf_t;
 
 typedef struct s_bdiffparam {
index 4b6e639..d3d9c84 100644 (file)
@@ -69,7 +69,24 @@ static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg) {
 }
 
 
-static void xdl_find_func(xdfile_t *xf, long i, char *buf, long sz, long *ll) {
+static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
+{
+       if (len > 0 &&
+                       (isalpha((unsigned char)*rec) || /* identifier? */
+                        *rec == '_' || /* also identifier? */
+                        *rec == '$')) { /* identifiers from VMS and other esoterico */
+               if (len > sz)
+                       len = sz;
+               while (0 < len && isspace((unsigned char)rec[len - 1]))
+                       len--;
+               memcpy(buf, rec, len);
+               return len;
+       }
+       return -1;
+}
+
+static void xdl_find_func(xdfile_t *xf, long i, char *buf, long sz, long *ll,
+               find_func_t ff, void *ff_priv) {
 
        /*
         * Be quite stupid about this for now.  Find a line in the old file
@@ -80,22 +97,12 @@ static void xdl_find_func(xdfile_t *xf, long i, char *buf, long sz, long *ll) {
        const char *rec;
        long len;
 
-       *ll = 0;
        while (i-- > 0) {
                len = xdl_get_rec(xf, i, &rec);
-               if (len > 0 &&
-                   (isalpha((unsigned char)*rec) || /* identifier? */
-                    *rec == '_' ||     /* also identifier? */
-                    *rec == '$')) {    /* mysterious GNU diff's invention */
-                       if (len > sz)
-                               len = sz;
-                       while (0 < len && isspace((unsigned char)rec[len - 1]))
-                               len--;
-                       memcpy(buf, rec, len);
-                       *ll = len;
+               if ((*ll = ff(rec, len, buf, sz, ff_priv)) >= 0)
                        return;
-               }
        }
+       *ll = 0;
 }
 
 
@@ -120,6 +127,7 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
        xdchange_t *xch, *xche;
        char funcbuf[80];
        long funclen = 0;
+       find_func_t ff = xecfg->find_func ?  xecfg->find_func : def_ff;
 
        if (xecfg->flags & XDL_EMIT_COMMON)
                return xdl_emit_common(xe, xscr, ecb, xecfg);
@@ -143,7 +151,8 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 
                if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
                        xdl_find_func(&xe->xdf1, s1, funcbuf,
-                                     sizeof(funcbuf), &funclen);
+                                     sizeof(funcbuf), &funclen,
+                                     ff, xecfg->find_func_priv);
                }
                if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
                                      funcbuf, funclen, ecb) < 0)