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fast-import: use skip_prefix for parsing input

Browse source 
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 <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff King 2014-06-18 15:49:12 -04:00 committed by Junio C Hamano
parent 95b567c7c3
commit 97313bef2a
1 changed files with 51 additions and 72 deletions
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123
fast-import.c
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@ -371,8 +371,8 @@ static volatile sig_atomic_t checkpoint_requested;
static int cat_blob_fd = STDOUT_FILENO; static int cat_blob_fd = STDOUT_FILENO;
static void parse_argv(void); static void parse_argv(void);
static void parse_cat_blob(void); static void parse_cat_blob(const char *p);
static void parse_ls(struct branch *b); static void parse_ls(const char *p, struct branch *b);
static void write_branch_report(FILE *rpt, struct branch *b) static void write_branch_report(FILE *rpt, struct branch *b)
{ {
@ -1861,6 +1861,8 @@ static int read_next_command(void)
} }
for (;;) { for (;;) {
const char *p;
if (unread_command_buf) { if (unread_command_buf) {
unread_command_buf = 0; unread_command_buf = 0;
} else { } else {
@ -1893,8 +1895,8 @@ static int read_next_command(void)
rc->prev->next = rc; rc->prev->next = rc;
cmd_tail = rc; cmd_tail = rc;
} }
if (starts_with(command_buf.buf, "cat-blob ")) { if (skip_prefix(command_buf.buf, "cat-blob ", &p)) {
parse_cat_blob(); parse_cat_blob(p);
continue; continue;
} }
if (command_buf.buf[0] == '#') if (command_buf.buf[0] == '#')
@ -2273,9 +2275,8 @@ static uintmax_t parse_mark_ref_space(const char **p)
return mark; 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; static struct strbuf uq = STRBUF_INIT;
const char *endp; const char *endp;
struct object_entry *oe; 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); 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; static struct strbuf uq = STRBUF_INIT;
const char *endp; const char *endp;
@ -2391,15 +2391,14 @@ static void file_change_d(struct branch *b)
tree_content_remove(&b->branch_tree, p, NULL, 1); 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 s_uq = STRBUF_INIT;
static struct strbuf d_uq = STRBUF_INIT; static struct strbuf d_uq = STRBUF_INIT;
const char *endp; const char *endp;
struct tree_entry leaf; struct tree_entry leaf;
s = command_buf.buf + 2;
strbuf_reset(&s_uq); strbuf_reset(&s_uq);
if (!unquote_c_style(&s_uq, s, &endp)) { if (!unquote_c_style(&s_uq, s, &endp)) {
if (*endp != ' ') if (*endp != ' ')
@ -2444,9 +2443,8 @@ static void file_change_cr(struct branch *b, int rename)
leaf.tree); 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; static struct strbuf uq = STRBUF_INIT;
struct object_entry *oe; struct object_entry *oe;
struct branch *s; struct branch *s;
@ -2587,7 +2585,7 @@ static int parse_from(struct branch *b)
const char *from; const char *from;
struct branch *s; struct branch *s;
if (!starts_with(command_buf.buf, "from ")) if (!skip_prefix(command_buf.buf, "from ", &from))
return 0; return 0;
if (b->branch_tree.tree) { if (b->branch_tree.tree) {
@ -2595,7 +2593,6 @@ static int parse_from(struct branch *b)
b->branch_tree.tree = NULL; b->branch_tree.tree = NULL;
} }
from = strchr(command_buf.buf, ' ') + 1;
s = lookup_branch(from); s = lookup_branch(from);
if (b == s) if (b == s)
die("Can't create a branch from itself: %s", b->name); 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; struct branch *s;
*count = 0; *count = 0;
while (starts_with(command_buf.buf, "merge ")) { while (skip_prefix(command_buf.buf, "merge ", &from)) {
from = strchr(command_buf.buf, ' ') + 1;
n = xmalloc(sizeof(*n)); n = xmalloc(sizeof(*n));
s = lookup_branch(from); s = lookup_branch(from);
if (s) if (s)
@ -2668,11 +2664,10 @@ static struct hash_list *parse_merge(unsigned int *count)
return list; return list;
} }
static void parse_new_commit(void) static void parse_new_commit(const char *arg)
{ {
static struct strbuf msg = STRBUF_INIT; static struct strbuf msg = STRBUF_INIT;
struct branch *b; struct branch *b;
char *sp;
char *author = NULL; char *author = NULL;
char *committer = NULL; char *committer = NULL;
struct hash_list *merge_list = NULL; struct hash_list *merge_list = NULL;
@ -2680,11 +2675,9 @@ static void parse_new_commit(void)
unsigned char prev_fanout, new_fanout; unsigned char prev_fanout, new_fanout;
const char *v; const char *v;
/* Obtain the branch name from the rest of our command */ b = lookup_branch(arg);
sp = strchr(command_buf.buf, ' ') + 1;
b = lookup_branch(sp);
if (!b) if (!b)
b = new_branch(sp); b = new_branch(arg);
read_next_command(); read_next_command();
parse_mark(); parse_mark();
@ -2713,20 +2706,20 @@ static void parse_new_commit(void)
/* file_change* */ /* file_change* */
while (command_buf.len > 0) { while (command_buf.len > 0) {
if (starts_with(command_buf.buf, "M ")) if (skip_prefix(command_buf.buf, "M ", &v))
file_change_m(b); file_change_m(v, b);
else if (starts_with(command_buf.buf, "D ")) else if (skip_prefix(command_buf.buf, "D ", &v))
file_change_d(b); file_change_d(v, b);
else if (starts_with(command_buf.buf, "R ")) else if (skip_prefix(command_buf.buf, "R ", &v))
file_change_cr(b, 1); file_change_cr(v, b, 1);
else if (starts_with(command_buf.buf, "C ")) else if (skip_prefix(command_buf.buf, "C ", &v))
file_change_cr(b, 0); file_change_cr(v, b, 0);
else if (starts_with(command_buf.buf, "N ")) else if (skip_prefix(command_buf.buf, "N ", &v))
note_change_n(b, &prev_fanout); note_change_n(v, b, &prev_fanout);
else if (!strcmp("deleteall", command_buf.buf)) else if (!strcmp("deleteall", command_buf.buf))
file_change_deleteall(b); file_change_deleteall(b);
else if (starts_with(command_buf.buf, "ls ")) else if (skip_prefix(command_buf.buf, "ls ", &v))
parse_ls(b); parse_ls(v, b);
else { else {
unread_command_buf = 1; unread_command_buf = 1;
break; break;
@ -2769,10 +2762,9 @@ static void parse_new_commit(void)
b->last_commit = object_count_by_type[OBJ_COMMIT]; 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; static struct strbuf msg = STRBUF_INIT;
char *sp;
const char *from; const char *from;
char *tagger; char *tagger;
struct branch *s; struct branch *s;
@ -2782,11 +2774,9 @@ static void parse_new_tag(void)
enum object_type type; enum object_type type;
const char *v; 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)); t = pool_alloc(sizeof(struct tag));
memset(t, 0, sizeof(struct tag)); memset(t, 0, sizeof(struct tag));
t->name = pool_strdup(sp); t->name = pool_strdup(arg);
if (last_tag) if (last_tag)
last_tag->next_tag = t; last_tag->next_tag = t;
else else
@ -2795,9 +2785,8 @@ static void parse_new_tag(void)
read_next_command(); read_next_command();
/* from ... */ /* 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); die("Expected from command, got %s", command_buf.buf);
from = strchr(command_buf.buf, ' ') + 1;
s = lookup_branch(from); s = lookup_branch(from);
if (s) { if (s) {
if (is_null_sha1(s->sha1)) if (is_null_sha1(s->sha1))
@ -2853,14 +2842,11 @@ static void parse_new_tag(void)
t->pack_id = pack_id; t->pack_id = pack_id;
} }
static void parse_reset_branch(void) static void parse_reset_branch(const char *arg)
{ {
struct branch *b; struct branch *b;
char *sp;
/* Obtain the branch name from the rest of our command */ b = lookup_branch(arg);
sp = strchr(command_buf.buf, ' ') + 1;
b = lookup_branch(sp);
if (b) { if (b) {
hashclr(b->sha1); hashclr(b->sha1);
hashclr(b->branch_tree.versions[0].sha1); hashclr(b->branch_tree.versions[0].sha1);
@ -2871,7 +2857,7 @@ static void parse_reset_branch(void)
} }
} }
else else
b = new_branch(sp); b = new_branch(arg);
read_next_command(); read_next_command();
parse_from(b); parse_from(b);
if (command_buf.len > 0) if (command_buf.len > 0)
@ -2929,14 +2915,12 @@ static void cat_blob(struct object_entry *oe, unsigned char sha1[20])
free(buf); free(buf);
} }
static void parse_cat_blob(void) static void parse_cat_blob(const char *p)
{ {
const char *p;
struct object_entry *oe = oe; struct object_entry *oe = oe;
unsigned char sha1[20]; unsigned char sha1[20];
/* cat-blob SP <object> LF */ /* cat-blob SP <object> LF */
p = command_buf.buf + strlen("cat-blob ");
if (*p == ':') { if (*p == ':') {
oe = find_mark(parse_mark_ref_eol(p)); oe = find_mark(parse_mark_ref_eol(p));
if (!oe) 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); 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 *root = NULL;
struct tree_entry leaf = {NULL}; struct tree_entry leaf = {NULL};
/* ls SP (<tree-ish> SP)? <path> */ /* ls SP (<tree-ish> SP)? <path> */
p = command_buf.buf + strlen("ls ");
if (*p == '"') { if (*p == '"') {
if (!b) if (!b)
die("Not in a commit: %s", command_buf.buf); 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; return 1;
} }
static void parse_feature(void) static void parse_feature(const char *feature)
{ {
char *feature = command_buf.buf + 8;
if (seen_data_command) if (seen_data_command)
die("Got feature command '%s' after data command", feature); 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); 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) if (seen_data_command)
die("Got option command '%s' after data command", option); 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_die_routine(die_nicely);
set_checkpoint_signal(); set_checkpoint_signal();
while (read_next_command() != EOF) { while (read_next_command() != EOF) {
const char *v;
if (!strcmp("blob", command_buf.buf)) if (!strcmp("blob", command_buf.buf))
parse_new_blob(); parse_new_blob();
else if (starts_with(command_buf.buf, "ls ")) else if (skip_prefix(command_buf.buf, "ls ", &v))
parse_ls(NULL); parse_ls(v, NULL);
else if (starts_with(command_buf.buf, "commit ")) else if (skip_prefix(command_buf.buf, "commit ", &v))
parse_new_commit(); parse_new_commit(v);
else if (starts_with(command_buf.buf, "tag ")) else if (skip_prefix(command_buf.buf, "tag ", &v))
parse_new_tag(); parse_new_tag(v);
else if (starts_with(command_buf.buf, "reset ")) else if (skip_prefix(command_buf.buf, "reset ", &v))
parse_reset_branch(); parse_reset_branch(v);
else if (!strcmp("checkpoint", command_buf.buf)) else if (!strcmp("checkpoint", command_buf.buf))
parse_checkpoint(); parse_checkpoint();
else if (!strcmp("done", command_buf.buf)) else if (!strcmp("done", command_buf.buf))
break; break;
else if (starts_with(command_buf.buf, "progress ")) else if (starts_with(command_buf.buf, "progress "))
parse_progress(); parse_progress();
else if (starts_with(command_buf.buf, "feature ")) else if (skip_prefix(command_buf.buf, "feature ", &v))
parse_feature(); parse_feature(v);
else if (starts_with(command_buf.buf, "option git ")) else if (skip_prefix(command_buf.buf, "option git ", &v))
parse_option(); parse_option(v);
else if (starts_with(command_buf.buf, "option ")) else if (starts_with(command_buf.buf, "option "))
/* ignore non-git options*/; /* ignore non-git options*/;
else else