[PATCH] Rework strbuf API and semantics.
A strbuf can be used to store byte arrays, or as an extended string
library. The `buf' member can be passed to any C legacy string function,
because strbuf operations always ensure there is a terminating \0 at the end
of the buffer, not accounted in the `len' field of the structure.
A strbuf can be used to generate a string/buffer whose final size is not
really known, and then "strbuf_detach" can be used to get the built buffer,
and keep the wrapping "strbuf" structure usable for further work again.
Other interesting feature: buffer_ensure(sb, size) ensure that there is
enough allocated space in `sb' to put `size' new octets of data in the
buffer. It helps avoiding reallocating data for nothing when the problem the
strbuf helps to solve has a known typical size.
Signed-off-by: Pierre Habouzit <madcoder@debian.org>
---
archive-tar.c | 65 +++++++++++++---------------------------------------
fast-import.c | 24 +++++++++---------
mktree.c | 4 +--
strbuf.c | 71 +++++++++++++++++++++++++++++++++++++++++++++-----------
strbuf.h | 34 +++++++++++++++++++++++++++
5 files changed, 120 insertions(+), 78 deletions(-)
diff --git a/archive-tar.c b/archive-tar.c
index 66fe3e3..ccdd7d5 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -78,19 +78,6 @@ static void write_trailer(void)
}
}
-static void strbuf_append_string(struct strbuf *sb, const char *s)
-{
- int slen = strlen(s);
- int total = sb->len + slen;
- if (total + 1 > sb->alloc) {
- sb->buf = xrealloc(sb->buf, total + 1);
- sb->alloc = total + 1;
- }
- memcpy(sb->buf + sb->len, s, slen);
- sb->len = total;
- sb->buf[total] = '\0';
-}
-
/*
* pax extended header records have the format "%u %s=%s\n". %u contains
* the size of the whole string (including the %u), the first %s is the
@@ -100,26 +87,17 @@ static void strbuf_append_string(struct strbuf *sb, const char *s)
static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
const char *value, unsigned int valuelen)
{
- char *p;
- int len, total, tmp;
+ int len, tmp;
/* "%u %s=%s\n" */
len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
for (tmp = len; tmp > 9; tmp /= 10)
len++;
- total = sb->len + len;
- if (total > sb->alloc) {
- sb->buf = xrealloc(sb->buf, total);
- sb->alloc = total;
- }
-
- p = sb->buf;
- p += sprintf(p, "%u %s=", len, keyword);
- memcpy(p, value, valuelen);
- p += valuelen;
- *p = '\n';
- sb->len = total;
+ strbuf_ensure(sb, len);
+ strbuf_addf(sb, "%u %s=", len, keyword);
+ strbuf_add(sb, value, valuelen);
+ strbuf_addch(sb, '\n');
}
static unsigned int ustar_header_chksum(const struct ustar_header *header)
@@ -153,8 +131,7 @@ static void write_entry(const unsigned char *sha1, struct strbuf *path,
struct strbuf ext_header;
memset(&header, 0, sizeof(header));
- ext_header.buf = NULL;
- ext_header.len = ext_header.alloc = 0;
+ strbuf_init(&ext_header);
if (!sha1) {
*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
@@ -225,8 +202,8 @@ static void write_entry(const unsigned char *sha1, struct strbuf *path,
if (ext_header.len > 0) {
write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
- free(ext_header.buf);
}
+ strbuf_wipe(&ext_header);
write_blocked(&header, sizeof(header));
if (S_ISREG(mode) && buffer && size > 0)
write_blocked(buffer, size);
@@ -235,11 +212,11 @@ static void write_entry(const unsigned char *sha1, struct strbuf *path,
static void write_global_extended_header(const unsigned char *sha1)
{
struct strbuf ext_header;
- ext_header.buf = NULL;
- ext_header.len = ext_header.alloc = 0;
+
+ strbuf_init(&ext_header);
strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
- free(ext_header.buf);
+ strbuf_wipe(&ext_header);
}
static int git_tar_config(const char *var, const char *value)
@@ -260,28 +237,18 @@ static int write_tar_entry(const unsigned char *sha1,
const char *base, int baselen,
const char *filename, unsigned mode, int stage)
{
- static struct strbuf path;
+ static struct strbuf path = STRBUF_INIT;
int filenamelen = strlen(filename);
void *buffer;
enum object_type type;
unsigned long size;
- if (!path.alloc) {
- path.buf = xmalloc(PATH_MAX);
- path.alloc = PATH_MAX;
- path.len = path.eof = 0;
- }
- if (path.alloc < baselen + filenamelen + 1) {
- free(path.buf);
- path.buf = xmalloc(baselen + filenamelen + 1);
- path.alloc = baselen + filenamelen + 1;
- }
- memcpy(path.buf, base, baselen);
- memcpy(path.buf + baselen, filename, filenamelen);
- path.len = baselen + filenamelen;
- path.buf[path.len] = '\0';
+ strbuf_ensure(&path, MAX(PATH_MAX, baselen + filenamelen + 1));
+ strbuf_reset(&path);
+ strbuf_add(&path, base, baselen);
+ strbuf_add(&path, filename, filenamelen);
if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
- strbuf_append_string(&path, "/");
+ strbuf_addch(&path, '/');
buffer = NULL;
size = 0;
} else {
diff --git a/fast-import.c b/fast-import.c
index 078079d..ab3927b 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -340,7 +340,7 @@ static struct tag *last_tag;
/* Input stream parsing */
static whenspec_type whenspec = WHENSPEC_RAW;
-static struct strbuf command_buf;
+static struct strbuf command_buf = STRBUF_INIT;
static int unread_command_buf;
static struct recent_command cmd_hist = {&cmd_hist, &cmd_hist, NULL};
static struct recent_command *cmd_tail = &cmd_hist;
@@ -1595,7 +1595,7 @@ static void read_next_command(void)
} else {
struct recent_command *rc;
- command_buf.buf = NULL;
+ strbuf_detach(&command_buf);
read_line(&command_buf, stdin, '\n');
if (command_buf.eof)
return;
@@ -1610,7 +1610,7 @@ static void read_next_command(void)
free(rc->buf);
}
- rc->buf = command_buf.buf;
+ rc->buf = command_buf.buf;
rc->prev = cmd_tail;
rc->next = cmd_hist.prev;
rc->prev->next = rc;
@@ -1649,7 +1649,9 @@ static void *cmd_data (size_t *size)
size_t sz = 8192, term_len = command_buf.len - 5 - 2;
length = 0;
buffer = xmalloc(sz);
- command_buf.buf = NULL;
+
+ /* XXX possible memory leak ? */
+ strbuf_detach(&command_buf);
for (;;) {
read_line(&command_buf, stdin, '\n');
if (command_buf.eof)
@@ -1657,11 +1659,9 @@ static void *cmd_data (size_t *size)
if (term_len == command_buf.len
&& !strcmp(term, command_buf.buf))
break;
- ALLOC_GROW(buffer, length + command_buf.len, sz);
- memcpy(buffer + length,
- command_buf.buf,
- command_buf.len - 1);
- length += command_buf.len - 1;
+ ALLOC_GROW(buffer, length + command_buf.len + 1, sz);
+ memcpy(buffer + length, command_buf.buf, command_buf.len);
+ length += command_buf.len;
buffer[length++] = '\n';
}
free(term);
@@ -2101,7 +2101,7 @@ static void cmd_new_commit(void)
}
/* file_change* */
- while (!command_buf.eof && command_buf.len > 1) {
+ while (!command_buf.eof && command_buf.len > 0) {
if (!prefixcmp(command_buf.buf, "M "))
file_change_m(b);
else if (!prefixcmp(command_buf.buf, "D "))
@@ -2256,7 +2256,7 @@ static void cmd_reset_branch(void)
else
b = new_branch(sp);
read_next_command();
- if (!cmd_from(b) && command_buf.len > 1)
+ if (!cmd_from(b) && command_buf.len > 0)
unread_command_buf = 1;
}
@@ -2273,7 +2273,7 @@ static void cmd_checkpoint(void)
static void cmd_progress(void)
{
- fwrite(command_buf.buf, 1, command_buf.len - 1, stdout);
+ fwrite(command_buf.buf, 1, command_buf.len, stdout);
fputc('\n', stdout);
fflush(stdout);
skip_optional_lf();
diff --git a/mktree.c b/mktree.c
index d86dde8..86de5eb 100644
--- a/mktree.c
+++ b/mktree.c
@@ -92,7 +92,6 @@ int main(int ac, char **av)
strbuf_init(&sb);
while (1) {
- int len;
char *ptr, *ntr;
unsigned mode;
enum object_type type;
@@ -101,7 +100,6 @@ int main(int ac, char **av)
read_line(&sb, stdin, line_termination);
if (sb.eof)
break;
- len = sb.len;
ptr = sb.buf;
/* Input is non-recursive ls-tree output format
* mode SP type SP sha1 TAB name
@@ -111,7 +109,7 @@ int main(int ac, char **av)
die("input format error: %s", sb.buf);
ptr = ntr + 1; /* type */
ntr = strchr(ptr, ' ');
- if (!ntr || sb.buf + len <= ntr + 41 ||
+ if (!ntr || sb.buf + sb.len <= ntr + 40 ||
ntr[41] != '\t' ||
get_sha1_hex(ntr + 1, sha1))
die("input format error: %s", sb.buf);
diff --git a/strbuf.c b/strbuf.c
index e33d06b..86d5965 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -2,40 +2,83 @@
#include "strbuf.h"
void strbuf_init(struct strbuf *sb) {
- sb->buf = NULL;
- sb->eof = sb->alloc = sb->len = 0;
+ memset(sb, 0, sizeof(*sb));
}
-static void strbuf_begin(struct strbuf *sb) {
+void strbuf_wipe(struct strbuf *sb) {
free(sb->buf);
- strbuf_init(sb);
+ memset(sb, 0, sizeof(*sb));
}
-static void inline strbuf_add(struct strbuf *sb, int ch) {
- if (sb->alloc <= sb->len) {
- sb->alloc = sb->alloc * 3 / 2 + 16;
+void strbuf_reset(struct strbuf *sb) {
+ if (sb->len)
+ sb->buf[sb->len = 0] = '\0';
+}
+
+char *strbuf_detach(struct strbuf *sb) {
+ char *res = sb->buf;
+ strbuf_init(sb);
+ return res;
+}
+
+void strbuf_ensure(struct strbuf *sb, int extra) {
+ if (sb->len + extra >= sb->alloc) {
+ while (sb->len + extra >= sb->alloc)
+ sb->alloc = sb->alloc * 3 / 2 + 16;
sb->buf = xrealloc(sb->buf, sb->alloc);
}
- sb->buf[sb->len++] = ch;
}
-static void strbuf_end(struct strbuf *sb) {
- strbuf_add(sb, 0);
+void strbuf_add(struct strbuf *sb, const void *data, int len) {
+ strbuf_ensure(sb, len);
+ memcpy(sb->buf + sb->len, data, len);
+ sb->len += len;
+ sb->buf[sb->len] = '\0';
+}
+
+void strbuf_addvf(struct strbuf *sb, const char *fmt, va_list ap)
+{
+ int len;
+ va_list ap2;
+
+ va_copy(ap2, ap);
+
+ len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
+ if (len < 0) {
+ len = 0;
+ }
+ if (len >= sb->alloc - sb->len) {
+ strbuf_ensure(sb, len);
+ len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap2);
+ if (len >= sb->alloc - sb->len) {
+ len = sb->alloc - sb->len - 1;
+ }
+ }
+ sb->len = sb->len + len;
+ sb->buf[sb->len] = '\0';
}
void read_line(struct strbuf *sb, FILE *fp, int term) {
int ch;
- strbuf_begin(sb);
if (feof(fp)) {
+ strbuf_wipe(sb);
sb->eof = 1;
return;
}
+
+ strbuf_reset(sb);
while ((ch = fgetc(fp)) != EOF) {
if (ch == term)
break;
- strbuf_add(sb, ch);
+ strbuf_ensure(sb, 1);
+ sb->buf[sb->len++] = ch;
}
- if (ch == EOF && sb->len == 0)
+ if (ch == EOF && sb->len == 0) {
+ strbuf_wipe(sb);
sb->eof = 1;
- strbuf_end(sb);
+ }
+
+ strbuf_ensure(sb, 1);
+ sb->buf[sb->len] = '\0';
}
+
diff --git a/strbuf.h b/strbuf.h
index 74cc012..ee72419 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -7,7 +7,41 @@ struct strbuf {
char *buf;
};
+#define STRBUF_INIT { 0, 0, 0, NULL }
+
+/* strbuf life cycle */
extern void strbuf_init(struct strbuf *);
+extern void strbuf_wipe(struct strbuf *);
+extern void strbuf_reset(struct strbuf *);
+extern char *strbuf_detach(struct strbuf *);
+
+
+extern void strbuf_ensure(struct strbuf *, int);
+extern void strbuf_add(struct strbuf *, const void *data, int len);
+
+static inline void strbuf_addstr(struct strbuf *sb, const char *s) {
+ strbuf_add(sb, s, strlen(s));
+}
+static inline void strbuf_addbuf(struct strbuf *sb, struct strbuf *sb2) {
+ strbuf_add(sb, sb2->buf, sb2->len);
+}
+static inline void strbuf_addch(struct strbuf *sb, int c) {
+ strbuf_ensure(sb, 1);
+ sb->buf[sb->len++] = c;
+ sb->buf[sb->len] = '\0';
+}
+
+__attribute__((format(printf,2,0)))
+extern void strbuf_addvf(struct strbuf *, const char *, va_list);
+
+static inline __attribute__((format(printf,2,3)))
+void strbuf_addf(struct strbuf *sb, const char *fmt, ...) {
+ va_list ap;
+ va_start(ap, fmt);
+ strbuf_addvf(sb, fmt, ap);
+ va_end(ap);
+}
+
extern void read_line(struct strbuf *, FILE *, int);
#endif /* STRBUF_H */
--
1.5.3
Pierre Habouzit <madcoder@debian.org>