Implement git remote rename
[gitweb.git] / diff.c
diff --git a/diff.c b/diff.c
index 5b9b074856f3b3a4d47d9e8f7ed6cd059a005d64..e368fef14fdccf63fc3525349841ae93aea93046 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -11,6 +11,7 @@
 #include "attr.h"
 #include "run-command.h"
 #include "utf8.h"
+#include "userdiff.h"
 
 #ifdef NO_FAST_WORKING_DIRECTORY
 #define FAST_WORKING_DIRECTORY 0
@@ -24,6 +25,7 @@ static int diff_suppress_blank_empty;
 int diff_use_color_default = -1;
 static const char *external_diff_cmd_cfg;
 int diff_auto_refresh_index = 1;
+static int diff_mnemonic_prefix;
 
 static char diff_colors[][COLOR_MAXLEN] = {
        "\033[m",       /* reset */
@@ -36,6 +38,9 @@ static char diff_colors[][COLOR_MAXLEN] = {
        "\033[41m",     /* WHITESPACE (red background) */
 };
 
+static void diff_filespec_load_driver(struct diff_filespec *one);
+static char *run_textconv(const char *, struct diff_filespec *, size_t *);
+
 static int parse_diff_color_slot(const char *var, int ofs)
 {
        if (!strcasecmp(var+ofs, "plain"))
@@ -55,80 +60,6 @@ static int parse_diff_color_slot(const char *var, int ofs)
        die("bad config variable '%s'", var);
 }
 
-static struct ll_diff_driver {
-       const char *name;
-       struct ll_diff_driver *next;
-       const char *cmd;
-} *user_diff, **user_diff_tail;
-
-/*
- * Currently there is only "diff.<drivername>.command" variable;
- * because there are "diff.color.<slot>" variables, we are parsing
- * this in a bit convoluted way to allow low level diff driver
- * called "color".
- */
-static int parse_lldiff_command(const char *var, const char *ep, const char *value)
-{
-       const char *name;
-       int namelen;
-       struct ll_diff_driver *drv;
-
-       name = var + 5;
-       namelen = ep - name;
-       for (drv = user_diff; drv; drv = drv->next)
-               if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
-                       break;
-       if (!drv) {
-               drv = xcalloc(1, sizeof(struct ll_diff_driver));
-               drv->name = xmemdupz(name, namelen);
-               if (!user_diff_tail)
-                       user_diff_tail = &user_diff;
-               *user_diff_tail = drv;
-               user_diff_tail = &(drv->next);
-       }
-
-       return git_config_string(&(drv->cmd), var, value);
-}
-
-/*
- * '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.
- */
-struct funcname_pattern_entry {
-       char *name;
-       char *pattern;
-       int cflags;
-};
-static struct funcname_pattern_list {
-       struct funcname_pattern_list *next;
-       struct funcname_pattern_entry e;
-} *funcname_pattern_list;
-
-static int parse_funcname_pattern(const char *var, const char *ep, const char *value, int cflags)
-{
-       const char *name;
-       int namelen;
-       struct funcname_pattern_list *pp;
-
-       name = var + 5; /* "diff." */
-       namelen = ep - name;
-
-       for (pp = funcname_pattern_list; pp; pp = pp->next)
-               if (!strncmp(pp->e.name, name, namelen) && !pp->e.name[namelen])
-                       break;
-       if (!pp) {
-               pp = xcalloc(1, sizeof(*pp));
-               pp->e.name = xmemdupz(name, namelen);
-               pp->next = funcname_pattern_list;
-               funcname_pattern_list = pp;
-       }
-       free(pp->e.pattern);
-       pp->e.pattern = xstrdup(value);
-       pp->e.cflags = cflags;
-       return 0;
-}
-
 /*
  * These are to give UI layer defaults.
  * The core-level commands such as git-diff-files should
@@ -155,13 +86,17 @@ int git_diff_ui_config(const char *var, const char *value, void *cb)
                diff_auto_refresh_index = git_config_bool(var, value);
                return 0;
        }
+       if (!strcmp(var, "diff.mnemonicprefix")) {
+               diff_mnemonic_prefix = git_config_bool(var, value);
+               return 0;
+       }
        if (!strcmp(var, "diff.external"))
                return git_config_string(&external_diff_cmd_cfg, var, value);
-       if (!prefixcmp(var, "diff.")) {
-               const char *ep = strrchr(var, '.');
 
-               if (ep != var + 4 && !strcmp(ep, ".command"))
-                       return parse_lldiff_command(var, ep, value);
+       switch (userdiff_config_porcelain(var, value)) {
+               case 0: break;
+               case -1: return -1;
+               default: return 0;
        }
 
        return git_diff_basic_config(var, value, cb);
@@ -188,21 +123,10 @@ int git_diff_basic_config(const char *var, const char *value, void *cb)
                return 0;
        }
 
-       if (!prefixcmp(var, "diff.")) {
-               const char *ep = strrchr(var, '.');
-               if (ep != var + 4) {
-                       if (!strcmp(ep, ".funcname")) {
-                               if (!value)
-                                       return config_error_nonbool(var);
-                               return parse_funcname_pattern(var, ep, value,
-                                       0);
-                       } else if (!strcmp(ep, ".xfuncname")) {
-                               if (!value)
-                                       return config_error_nonbool(var);
-                               return parse_funcname_pattern(var, ep, value,
-                                       REG_EXTENDED);
-                       }
-               }
+       switch (userdiff_config_basic(var, value)) {
+               case 0: break;
+               case -1: return -1;
+               default: return 0;
        }
 
        return git_color_default_config(var, value, cb);
@@ -212,9 +136,8 @@ static char *quote_two(const char *one, const char *two)
 {
        int need_one = quote_c_style(one, NULL, NULL, 1);
        int need_two = quote_c_style(two, NULL, NULL, 1);
-       struct strbuf res;
+       struct strbuf res = STRBUF_INIT;
 
-       strbuf_init(&res, 0);
        if (need_one + need_two) {
                strbuf_addch(&res, '"');
                quote_c_style(one, &res, NULL, 1);
@@ -323,6 +246,15 @@ static void emit_rewrite_diff(const char *name_a,
        const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
        const char *reset = diff_get_color(color_diff, DIFF_RESET);
        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
+       const char *a_prefix, *b_prefix;
+
+       if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
+               a_prefix = o->b_prefix;
+               b_prefix = o->a_prefix;
+       } else {
+               a_prefix = o->a_prefix;
+               b_prefix = o->b_prefix;
+       }
 
        name_a += (*name_a == '/');
        name_b += (*name_b == '/');
@@ -331,8 +263,8 @@ static void emit_rewrite_diff(const char *name_a,
 
        strbuf_reset(&a_name);
        strbuf_reset(&b_name);
-       quote_two_c_style(&a_name, o->a_prefix, name_a, 0);
-       quote_two_c_style(&b_name, o->b_prefix, name_b, 0);
+       quote_two_c_style(&a_name, a_prefix, name_a, 0);
+       quote_two_c_style(&b_name, b_prefix, name_b, 0);
 
        diff_populate_filespec(one, 0);
        diff_populate_filespec(two, 0);
@@ -361,8 +293,19 @@ static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
        }
        else if (diff_populate_filespec(one, 0))
                return -1;
-       mf->ptr = one->data;
-       mf->size = one->size;
+
+       diff_filespec_load_driver(one);
+       if (one->driver->textconv) {
+               size_t size;
+               mf->ptr = run_textconv(one->driver->textconv, one, &size);
+               if (!mf->ptr)
+                       return -1;
+               mf->size = size;
+       }
+       else {
+               mf->ptr = one->data;
+               mf->size = one->size;
+       }
        return 0;
 }
 
@@ -669,7 +612,7 @@ static char *pprint_rename(const char *a, const char *b)
 {
        const char *old = a;
        const char *new = b;
-       struct strbuf name;
+       struct strbuf name = STRBUF_INIT;
        int pfx_length, sfx_length;
        int len_a = strlen(a);
        int len_b = strlen(b);
@@ -677,7 +620,6 @@ static char *pprint_rename(const char *a, const char *b)
        int qlen_a = quote_c_style(a, NULL, NULL, 0);
        int qlen_b = quote_c_style(b, NULL, NULL, 0);
 
-       strbuf_init(&name, 0);
        if (qlen_a || qlen_b) {
                quote_c_style(a, &name, NULL, 0);
                strbuf_addstr(&name, " => ");
@@ -820,8 +762,7 @@ static void fill_print_name(struct diffstat_file *file)
                return;
 
        if (!file->is_renamed) {
-               struct strbuf buf;
-               strbuf_init(&buf, 0);
+               struct strbuf buf = STRBUF_INIT;
                if (quote_c_style(file->name, &buf, NULL, 0)) {
                        pname = strbuf_detach(&buf, NULL);
                } else {
@@ -1128,9 +1069,13 @@ static void show_dirstat(struct diff_options *options)
                /*
                 * Original minus copied is the removed material,
                 * added is the new material.  They are both damages
-                * made to the preimage.
+                * made to the preimage. In --dirstat-by-file mode, count
+                * damaged files, not damaged lines. This is done by
+                * counting only a single damaged line per file.
                 */
                damage = (p->one->size - copied) + added;
+               if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE) && damage > 0)
+                       damage = 1;
 
                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
                dir.files[dir.nr].name = name;
@@ -1337,126 +1282,45 @@ static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two)
        emit_binary_diff_body(file, two, one);
 }
 
-static void setup_diff_attr_check(struct git_attr_check *check)
+void diff_filespec_load_driver(struct diff_filespec *one)
 {
-       static struct git_attr *attr_diff;
-
-       if (!attr_diff) {
-               attr_diff = git_attr("diff", 4);
-       }
-       check[0].attr = attr_diff;
+       if (!one->driver)
+               one->driver = userdiff_find_by_path(one->path);
+       if (!one->driver)
+               one->driver = userdiff_find_by_name("default");
 }
 
-static void diff_filespec_check_attr(struct diff_filespec *one)
+int diff_filespec_is_binary(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;
-
-               /* binaryness */
-               value = attr_diff_check.value;
-               if (ATTR_TRUE(value))
-                       ;
-               else if (ATTR_FALSE(value))
-                       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 (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);
+       if (one->is_binary == -1) {
+               diff_filespec_load_driver(one);
+               if (one->driver->binary != -1)
+                       one->is_binary = one->driver->binary;
+               else {
+                       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);
+                       if (one->is_binary == -1)
+                               one->is_binary = 0;
+               }
        }
+       return one->is_binary;
 }
 
-int diff_filespec_is_binary(struct diff_filespec *one)
+static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
 {
-       diff_filespec_check_attr(one);
-       return one->is_binary;
+       diff_filespec_load_driver(one);
+       return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
 }
 
-static const struct funcname_pattern_entry *funcname_pattern(const char *ident)
-{
-       struct funcname_pattern_list *pp;
-
-       for (pp = funcname_pattern_list; pp; pp = pp->next)
-               if (!strcmp(ident, pp->e.name))
-                       return &pp->e;
-       return NULL;
-}
-
-static const struct funcname_pattern_entry builtin_funcname_pattern[] = {
-       { "bibtex", "(@[a-zA-Z]{1,}[ \t]*\{{0,1}[ \t]*[^ \t\"@',\\#}{~%]*).*$",
-         REG_EXTENDED },
-       { "html", "^\\s*\\(<[Hh][1-6]\\s.*>.*\\)$", 0 },
-       { "java",
-         "!^[ \t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)\n"
-         "^[ \t]*(([ \t]*[A-Za-z_][A-Za-z_0-9]*){2,}[ \t]*\\([^;]*)$",
-         REG_EXTENDED },
-       { "pascal",
-         "^((procedure|function|constructor|destructor|interface|"
-               "implementation|initialization|finalization)[ \t]*.*)$"
-         "|"
-         "^(.*=[ \t]*(class|record).*)$",
-         REG_EXTENDED },
-       { "php", "^[\t ]*\\(\\(function\\|class\\).*\\)", 0 },
-       { "python", "^\\s*\\(\\(class\\|def\\)\\s.*\\)$", 0 },
-       { "ruby", "^[ \t]*((class|module|def)[ \t].*)$",
-         REG_EXTENDED },
-       { "tex",
-         "^(\\\\((sub)*section|chapter|part)\\*{0,1}\{.*)$",
-         REG_EXTENDED },
-};
-
-static const struct funcname_pattern_entry *diff_funcname_pattern(struct diff_filespec *one)
+void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
 {
-       const char *ident;
-       const struct funcname_pattern_entry *pe;
-       int i;
-
-       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. */
-       pe = funcname_pattern(ident);
-       if (pe)
-               return pe;
-
-       /*
-        * And define built-in fallback patterns here.  Note that
-        * these can be overridden by the user's config settings.
-        */
-       for (i = 0; i < ARRAY_SIZE(builtin_funcname_pattern); i++)
-               if (!strcmp(ident, builtin_funcname_pattern[i].name))
-                       return &builtin_funcname_pattern[i];
-
-       return NULL;
+       if (!options->a_prefix)
+               options->a_prefix = a;
+       if (!options->b_prefix)
+               options->b_prefix = b;
 }
 
 static void builtin_diff(const char *name_a,
@@ -1472,9 +1336,23 @@ static void builtin_diff(const char *name_a,
        char *a_one, *b_two;
        const char *set = diff_get_color_opt(o, DIFF_METAINFO);
        const char *reset = diff_get_color_opt(o, DIFF_RESET);
+       const char *a_prefix, *b_prefix;
+
+       diff_set_mnemonic_prefix(o, "a/", "b/");
+       if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
+               a_prefix = o->b_prefix;
+               b_prefix = o->a_prefix;
+       } else {
+               a_prefix = o->a_prefix;
+               b_prefix = o->b_prefix;
+       }
+
+       /* Never use a non-valid filename anywhere if at all possible */
+       name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
+       name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
 
-       a_one = quote_two(o->a_prefix, name_a + (*name_a == '/'));
-       b_two = quote_two(o->b_prefix, name_b + (*name_b == '/'));
+       a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
+       b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
        fprintf(o->file, "%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
@@ -1532,7 +1410,7 @@ static void builtin_diff(const char *name_a,
                xdemitconf_t xecfg;
                xdemitcb_t ecb;
                struct emit_callback ecbdata;
-               const struct funcname_pattern_entry *pe;
+               const struct userdiff_funcname *pe;
 
                pe = diff_funcname_pattern(one);
                if (!pe)
@@ -1686,6 +1564,7 @@ struct diff_filespec *alloc_filespec(const char *path)
        spec->path = (char *)(spec + 1);
        memcpy(spec->path, path, namelen+1);
        spec->count = 1;
+       spec->is_binary = -1;
        return spec;
 }
 
@@ -1770,10 +1649,9 @@ static int reuse_worktree_file(const char *name, const unsigned char *sha1, int
 
 static int populate_from_stdin(struct diff_filespec *s)
 {
-       struct strbuf buf;
+       struct strbuf buf = STRBUF_INIT;
        size_t size = 0;
 
-       strbuf_init(&buf, 0);
        if (strbuf_read(&buf, 0, 0) < 0)
                return error("error while reading from stdin %s",
                                     strerror(errno));
@@ -1825,7 +1703,7 @@ int diff_populate_filespec(struct diff_filespec *s, int size_only)
 
        if (!s->sha1_valid ||
            reuse_worktree_file(s->path, s->sha1, 0)) {
-               struct strbuf buf;
+               struct strbuf buf = STRBUF_INIT;
                struct stat st;
                int fd;
 
@@ -1868,7 +1746,6 @@ int diff_populate_filespec(struct diff_filespec *s, int size_only)
                /*
                 * Convert from working tree format to canonical git format
                 */
-               strbuf_init(&buf, 0);
                if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
                        size_t size = 0;
                        munmap(s->data, s->size);
@@ -2072,29 +1949,6 @@ static void run_external_diff(const char *pgm,
        }
 }
 
-static const char *external_diff_attr(const char *name)
-{
-       struct git_attr_check attr_diff_check;
-
-       if (!name)
-               return NULL;
-
-       setup_diff_attr_check(&attr_diff_check);
-       if (!git_checkattr(name, 1, &attr_diff_check)) {
-               const char *value = attr_diff_check.value;
-               if (!ATTR_TRUE(value) &&
-                   !ATTR_FALSE(value) &&
-                   !ATTR_UNSET(value)) {
-                       struct ll_diff_driver *drv;
-
-                       for (drv = user_diff; drv; drv = drv->next)
-                               if (!strcmp(drv->name, value))
-                                       return drv->cmd;
-               }
-       }
-       return NULL;
-}
-
 static void run_diff_cmd(const char *pgm,
                         const char *name,
                         const char *other,
@@ -2108,9 +1962,9 @@ static void run_diff_cmd(const char *pgm,
        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
                pgm = NULL;
        else {
-               const char *cmd = external_diff_attr(attr_path);
-               if (cmd)
-                       pgm = cmd;
+               struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
+               if (drv && drv->external)
+                       pgm = drv->external;
        }
 
        if (pgm) {
@@ -2331,8 +2185,10 @@ void diff_setup(struct diff_options *options)
                DIFF_OPT_CLR(options, COLOR_DIFF);
        options->detect_rename = diff_detect_rename_default;
 
-       options->a_prefix = "a/";
-       options->b_prefix = "b/";
+       if (!diff_mnemonic_prefix) {
+               options->a_prefix = "a/";
+               options->b_prefix = "b/";
+       }
 }
 
 int diff_setup_done(struct diff_options *options)
@@ -2415,13 +2271,6 @@ int diff_setup_done(struct diff_options *options)
                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
        }
 
-       /*
-        * If we postprocess in diffcore, we cannot simply return
-        * upon the first hit.  We need to run diff as usual.
-        */
-       if (options->pickaxe || options->filter)
-               DIFF_OPT_CLR(options, QUIET);
-
        return 0;
 }
 
@@ -2496,6 +2345,10 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
        else if (!strcmp(arg, "--cumulative")) {
                options->output_format |= DIFF_FORMAT_DIRSTAT;
                DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
+       } else if (opt_arg(arg, 0, "dirstat-by-file",
+                          &options->dirstat_percent)) {
+               options->output_format |= DIFF_FORMAT_DIRSTAT;
+               DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
        }
        else if (!strcmp(arg, "--check"))
                options->output_format |= DIFF_FORMAT_CHECKDIFF;
@@ -3052,7 +2905,7 @@ static void diff_summary(FILE *file, struct diff_filepair *p)
 }
 
 struct patch_id_t {
-       SHA_CTX *ctx;
+       git_SHA_CTX *ctx;
        int patchlen;
 };
 
@@ -3080,7 +2933,7 @@ static void patch_id_consume(void *priv, char *line, unsigned long len)
 
        new_len = remove_space(line, len);
 
-       SHA1_Update(data->ctx, line, new_len);
+       git_SHA1_Update(data->ctx, line, new_len);
        data->patchlen += new_len;
 }
 
@@ -3089,11 +2942,11 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
 {
        struct diff_queue_struct *q = &diff_queued_diff;
        int i;
-       SHA_CTX ctx;
+       git_SHA_CTX ctx;
        struct patch_id_t data;
        char buffer[PATH_MAX * 4 + 20];
 
-       SHA1_Init(&ctx);
+       git_SHA1_Init(&ctx);
        memset(&data, 0, sizeof(struct patch_id_t));
        data.ctx = &ctx;
 
@@ -3155,7 +3008,7 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
                                        len2, p->two->path,
                                        len1, p->one->path,
                                        len2, p->two->path);
-               SHA1_Update(&ctx, buffer, len1);
+               git_SHA1_Update(&ctx, buffer, len1);
 
                xpp.flags = XDF_NEED_MINIMAL;
                xecfg.ctxlen = 3;
@@ -3164,7 +3017,7 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
                              &xpp, &xecfg, &ecb);
        }
 
-       SHA1_Final(sha1, &ctx);
+       git_SHA1_Final(sha1, &ctx);
        return 0;
 }
 
@@ -3409,10 +3262,7 @@ static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
 
 void diffcore_std(struct diff_options *options)
 {
-       if (DIFF_OPT_TST(options, QUIET))
-               return;
-
-       if (options->skip_stat_unmatch && !DIFF_OPT_TST(options, FIND_COPIES_HARDER))
+       if (options->skip_stat_unmatch)
                diffcore_skip_stat_unmatch(options);
        if (options->break_opt != -1)
                diffcore_break(options->break_opt);
@@ -3537,3 +3387,34 @@ void diff_unmerge(struct diff_options *options,
        fill_filespec(one, sha1, mode);
        diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
 }
+
+static char *run_textconv(const char *pgm, struct diff_filespec *spec,
+               size_t *outsize)
+{
+       struct diff_tempfile temp;
+       const char *argv[3];
+       const char **arg = argv;
+       struct child_process child;
+       struct strbuf buf = STRBUF_INIT;
+
+       prepare_temp_file(spec->path, &temp, spec);
+       *arg++ = pgm;
+       *arg++ = temp.name;
+       *arg = NULL;
+
+       memset(&child, 0, sizeof(child));
+       child.argv = argv;
+       child.out = -1;
+       if (start_command(&child) != 0 ||
+           strbuf_read(&buf, child.out, 0) < 0 ||
+           finish_command(&child) != 0) {
+               if (temp.name == temp.tmp_path)
+                       unlink(temp.name);
+               error("error running textconv command '%s'", pgm);
+               return NULL;
+       }
+       if (temp.name == temp.tmp_path)
+               unlink(temp.name);
+
+       return strbuf_detach(&buf, outsize);
+}