From 97313bef2a16eb8b3d40830204c20c34ba9d6554 Mon Sep 17 00:00:00 2001 From: Jeff King Date: Wed, 18 Jun 2014 15:49:12 -0400 Subject: [PATCH] fast-import: use skip_prefix for parsing input Fast-import does a lot of parsing of commands and dispatching to sub-functions. For example, given "option foo", we might recognize "option " using starts_with, and then hand it off to parse_option() to do the rest. However, we do not let parse_option know that we have parsed the first part already. It gets the full buffer, and has to skip past the uninteresting bits. Some functions simply add a magic constant: char *option = command_buf.buf + 7; Others use strlen: char *option = command_buf.buf + strlen("option "); And others use strchr: char *option = strchr(command_buf.buf, ' ') + 1; All of these are brittle and easy to get wrong (especially given that the starts_with call and the code that assumes the presence of the prefix are far apart). Instead, we can use skip_prefix, and just pass each handler a pointer to its arguments. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- fast-import.c | 123 ++++++++++++++++++++++++---------------------------------- 1 file changed, 51 insertions(+), 72 deletions(-) diff --git a/fast-import.c b/fast-import.c index a3ffe3063c..c608fc68a0 100644 --- a/fast-import.c +++ b/fast-import.c @@ -371,8 +371,8 @@ static volatile sig_atomic_t checkpoint_requested; static int cat_blob_fd = STDOUT_FILENO; static void parse_argv(void); -static void parse_cat_blob(void); -static void parse_ls(struct branch *b); +static void parse_cat_blob(const char *p); +static void parse_ls(const char *p, struct branch *b); static void write_branch_report(FILE *rpt, struct branch *b) { @@ -1861,6 +1861,8 @@ static int read_next_command(void) } for (;;) { + const char *p; + if (unread_command_buf) { unread_command_buf = 0; } else { @@ -1893,8 +1895,8 @@ static int read_next_command(void) rc->prev->next = rc; cmd_tail = rc; } - if (starts_with(command_buf.buf, "cat-blob ")) { - parse_cat_blob(); + if (skip_prefix(command_buf.buf, "cat-blob ", &p)) { + parse_cat_blob(p); continue; } if (command_buf.buf[0] == '#') @@ -2273,9 +2275,8 @@ static uintmax_t parse_mark_ref_space(const char **p) return mark; } -static void file_change_m(struct branch *b) +static void file_change_m(const char *p, struct branch *b) { - const char *p = command_buf.buf + 2; static struct strbuf uq = STRBUF_INIT; const char *endp; struct object_entry *oe; @@ -2376,9 +2377,8 @@ static void file_change_m(struct branch *b) tree_content_set(&b->branch_tree, p, sha1, mode, NULL); } -static void file_change_d(struct branch *b) +static void file_change_d(const char *p, struct branch *b) { - const char *p = command_buf.buf + 2; static struct strbuf uq = STRBUF_INIT; const char *endp; @@ -2391,15 +2391,14 @@ static void file_change_d(struct branch *b) tree_content_remove(&b->branch_tree, p, NULL, 1); } -static void file_change_cr(struct branch *b, int rename) +static void file_change_cr(const char *s, struct branch *b, int rename) { - const char *s, *d; + const char *d; static struct strbuf s_uq = STRBUF_INIT; static struct strbuf d_uq = STRBUF_INIT; const char *endp; struct tree_entry leaf; - s = command_buf.buf + 2; strbuf_reset(&s_uq); if (!unquote_c_style(&s_uq, s, &endp)) { if (*endp != ' ') @@ -2444,9 +2443,8 @@ static void file_change_cr(struct branch *b, int rename) leaf.tree); } -static void note_change_n(struct branch *b, unsigned char *old_fanout) +static void note_change_n(const char *p, struct branch *b, unsigned char *old_fanout) { - const char *p = command_buf.buf + 2; static struct strbuf uq = STRBUF_INIT; struct object_entry *oe; struct branch *s; @@ -2587,7 +2585,7 @@ static int parse_from(struct branch *b) const char *from; struct branch *s; - if (!starts_with(command_buf.buf, "from ")) + if (!skip_prefix(command_buf.buf, "from ", &from)) return 0; if (b->branch_tree.tree) { @@ -2595,7 +2593,6 @@ static int parse_from(struct branch *b) b->branch_tree.tree = NULL; } - from = strchr(command_buf.buf, ' ') + 1; s = lookup_branch(from); if (b == s) die("Can't create a branch from itself: %s", b->name); @@ -2636,8 +2633,7 @@ static struct hash_list *parse_merge(unsigned int *count) struct branch *s; *count = 0; - while (starts_with(command_buf.buf, "merge ")) { - from = strchr(command_buf.buf, ' ') + 1; + while (skip_prefix(command_buf.buf, "merge ", &from)) { n = xmalloc(sizeof(*n)); s = lookup_branch(from); if (s) @@ -2668,11 +2664,10 @@ static struct hash_list *parse_merge(unsigned int *count) return list; } -static void parse_new_commit(void) +static void parse_new_commit(const char *arg) { static struct strbuf msg = STRBUF_INIT; struct branch *b; - char *sp; char *author = NULL; char *committer = NULL; struct hash_list *merge_list = NULL; @@ -2680,11 +2675,9 @@ static void parse_new_commit(void) unsigned char prev_fanout, new_fanout; const char *v; - /* Obtain the branch name from the rest of our command */ - sp = strchr(command_buf.buf, ' ') + 1; - b = lookup_branch(sp); + b = lookup_branch(arg); if (!b) - b = new_branch(sp); + b = new_branch(arg); read_next_command(); parse_mark(); @@ -2713,20 +2706,20 @@ static void parse_new_commit(void) /* file_change* */ while (command_buf.len > 0) { - if (starts_with(command_buf.buf, "M ")) - file_change_m(b); - else if (starts_with(command_buf.buf, "D ")) - file_change_d(b); - else if (starts_with(command_buf.buf, "R ")) - file_change_cr(b, 1); - else if (starts_with(command_buf.buf, "C ")) - file_change_cr(b, 0); - else if (starts_with(command_buf.buf, "N ")) - note_change_n(b, &prev_fanout); + if (skip_prefix(command_buf.buf, "M ", &v)) + file_change_m(v, b); + else if (skip_prefix(command_buf.buf, "D ", &v)) + file_change_d(v, b); + else if (skip_prefix(command_buf.buf, "R ", &v)) + file_change_cr(v, b, 1); + else if (skip_prefix(command_buf.buf, "C ", &v)) + file_change_cr(v, b, 0); + else if (skip_prefix(command_buf.buf, "N ", &v)) + note_change_n(v, b, &prev_fanout); else if (!strcmp("deleteall", command_buf.buf)) file_change_deleteall(b); - else if (starts_with(command_buf.buf, "ls ")) - parse_ls(b); + else if (skip_prefix(command_buf.buf, "ls ", &v)) + parse_ls(v, b); else { unread_command_buf = 1; break; @@ -2769,10 +2762,9 @@ static void parse_new_commit(void) b->last_commit = object_count_by_type[OBJ_COMMIT]; } -static void parse_new_tag(void) +static void parse_new_tag(const char *arg) { static struct strbuf msg = STRBUF_INIT; - char *sp; const char *from; char *tagger; struct branch *s; @@ -2782,11 +2774,9 @@ static void parse_new_tag(void) enum object_type type; const char *v; - /* Obtain the new tag name from the rest of our command */ - sp = strchr(command_buf.buf, ' ') + 1; t = pool_alloc(sizeof(struct tag)); memset(t, 0, sizeof(struct tag)); - t->name = pool_strdup(sp); + t->name = pool_strdup(arg); if (last_tag) last_tag->next_tag = t; else @@ -2795,9 +2785,8 @@ static void parse_new_tag(void) read_next_command(); /* from ... */ - if (!starts_with(command_buf.buf, "from ")) + if (!skip_prefix(command_buf.buf, "from ", &from)) die("Expected from command, got %s", command_buf.buf); - from = strchr(command_buf.buf, ' ') + 1; s = lookup_branch(from); if (s) { if (is_null_sha1(s->sha1)) @@ -2853,14 +2842,11 @@ static void parse_new_tag(void) t->pack_id = pack_id; } -static void parse_reset_branch(void) +static void parse_reset_branch(const char *arg) { struct branch *b; - char *sp; - /* Obtain the branch name from the rest of our command */ - sp = strchr(command_buf.buf, ' ') + 1; - b = lookup_branch(sp); + b = lookup_branch(arg); if (b) { hashclr(b->sha1); hashclr(b->branch_tree.versions[0].sha1); @@ -2871,7 +2857,7 @@ static void parse_reset_branch(void) } } else - b = new_branch(sp); + b = new_branch(arg); read_next_command(); parse_from(b); if (command_buf.len > 0) @@ -2929,14 +2915,12 @@ static void cat_blob(struct object_entry *oe, unsigned char sha1[20]) free(buf); } -static void parse_cat_blob(void) +static void parse_cat_blob(const char *p) { - const char *p; struct object_entry *oe = oe; unsigned char sha1[20]; /* cat-blob SP LF */ - p = command_buf.buf + strlen("cat-blob "); if (*p == ':') { oe = find_mark(parse_mark_ref_eol(p)); if (!oe) @@ -3053,14 +3037,12 @@ static void print_ls(int mode, const unsigned char *sha1, const char *path) cat_blob_write(line.buf, line.len); } -static void parse_ls(struct branch *b) +static void parse_ls(const char *p, struct branch *b) { - const char *p; struct tree_entry *root = NULL; struct tree_entry leaf = {NULL}; /* ls SP ( SP)? */ - p = command_buf.buf + strlen("ls "); if (*p == '"') { if (!b) die("Not in a commit: %s", command_buf.buf); @@ -3276,10 +3258,8 @@ static int parse_one_feature(const char *feature, int from_stream) return 1; } -static void parse_feature(void) +static void parse_feature(const char *feature) { - char *feature = command_buf.buf + 8; - if (seen_data_command) die("Got feature command '%s' after data command", feature); @@ -3289,10 +3269,8 @@ static void parse_feature(void) die("This version of fast-import does not support feature %s.", feature); } -static void parse_option(void) +static void parse_option(const char *option) { - char *option = command_buf.buf + 11; - if (seen_data_command) die("Got option command '%s' after data command", option); @@ -3408,26 +3386,27 @@ int main(int argc, char **argv) set_die_routine(die_nicely); set_checkpoint_signal(); while (read_next_command() != EOF) { + const char *v; if (!strcmp("blob", command_buf.buf)) parse_new_blob(); - else if (starts_with(command_buf.buf, "ls ")) - parse_ls(NULL); - else if (starts_with(command_buf.buf, "commit ")) - parse_new_commit(); - else if (starts_with(command_buf.buf, "tag ")) - parse_new_tag(); - else if (starts_with(command_buf.buf, "reset ")) - parse_reset_branch(); + else if (skip_prefix(command_buf.buf, "ls ", &v)) + parse_ls(v, NULL); + else if (skip_prefix(command_buf.buf, "commit ", &v)) + parse_new_commit(v); + else if (skip_prefix(command_buf.buf, "tag ", &v)) + parse_new_tag(v); + else if (skip_prefix(command_buf.buf, "reset ", &v)) + parse_reset_branch(v); else if (!strcmp("checkpoint", command_buf.buf)) parse_checkpoint(); else if (!strcmp("done", command_buf.buf)) break; else if (starts_with(command_buf.buf, "progress ")) parse_progress(); - else if (starts_with(command_buf.buf, "feature ")) - parse_feature(); - else if (starts_with(command_buf.buf, "option git ")) - parse_option(); + else if (skip_prefix(command_buf.buf, "feature ", &v)) + parse_feature(v); + else if (skip_prefix(command_buf.buf, "option git ", &v)) + parse_option(v); else if (starts_with(command_buf.buf, "option ")) /* ignore non-git options*/; else -- 2.11.4.GIT