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code/git/c2abd83fea0c332e907f5bc23bea4eeca091a86b/./convert.c
blob: 1816e977b7b13782003fc78a9de9b47cd3554a32 [file]
#include "cache.h"
#include "attr.h"
#include "run-command.h"
/*
* convert.c - convert a file when checking it out and checking it in.
*
* This should use the pathname to decide on whether it wants to do some
* more interesting conversions (automatic gzip/unzip, general format
* conversions etc etc), but by default it just does automatic CRLF<->LF
* translation when the "auto_crlf" option is set.
*/
#define CRLF_GUESS (-1)
#define CRLF_BINARY 0
#define CRLF_TEXT 1
#define CRLF_INPUT 2
struct text_stat {
/* NUL, CR, LF and CRLF counts */
unsigned nul, cr, lf, crlf;
/* These are just approximations! */
unsigned printable, nonprintable;
};
static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
{
unsigned long i;
memset(stats, 0, sizeof(*stats));
for (i = 0; i < size; i++) {
unsigned char c = buf[i];
if (c == '\r') {
stats->cr++;
if (i+1 < size && buf[i+1] == '\n')
stats->crlf++;
continue;
}
if (c == '\n') {
stats->lf++;
continue;
}
if (c == 127)
/* DEL */
stats->nonprintable++;
else if (c < 32) {
switch (c) {
/* BS, HT, ESC and FF */
case '\b': case '\t': case '\033': case '\014':
stats->printable++;
break;
case 0:
stats->nul++;
/* fall through */
default:
stats->nonprintable++;
}
}
else
stats->printable++;
}
/* If file ends with EOF then don't count this EOF as non-printable. */
if (size >= 1 && buf[size-1] == '\032')
stats->nonprintable--;
}
/*
* The same heuristics as diff.c::mmfile_is_binary()
*/
static int is_binary(unsigned long size, struct text_stat *stats)
{
if (stats->nul)
return 1;
if ((stats->printable >> 7) < stats->nonprintable)
return 1;
/*
* Other heuristics? Average line length might be relevant,
* as might LF vs CR vs CRLF counts..
*
* NOTE! It might be normal to have a low ratio of CRLF to LF
* (somebody starts with a LF-only file and edits it with an editor
* that adds CRLF only to lines that are added..). But do we
* want to support CR-only? Probably not.
*/
return 0;
}
static void check_safe_crlf(const char *path, int action,
struct text_stat *stats, enum safe_crlf checksafe)
{
if (!checksafe)
return;
if (action == CRLF_INPUT || auto_crlf <= 0) {
/*
* CRLFs would not be restored by checkout:
* check if we'd remove CRLFs
*/
if (stats->crlf) {
if (checksafe == SAFE_CRLF_WARN)
warning("CRLF will be replaced by LF in %s.", path);
else /* i.e. SAFE_CRLF_FAIL */
die("CRLF would be replaced by LF in %s.", path);
}
} else if (auto_crlf > 0) {
/*
* CRLFs would be added by checkout:
* check if we have "naked" LFs
*/
if (stats->lf != stats->crlf) {
if (checksafe == SAFE_CRLF_WARN)
warning("LF will be replaced by CRLF in %s", path);
else /* i.e. SAFE_CRLF_FAIL */
die("LF would be replaced by CRLF in %s", path);
}
}
}
static int crlf_to_git(const char *path, const char *src, size_t len,
struct strbuf *buf, int action, enum safe_crlf checksafe)
{
struct text_stat stats;
char *dst;
if ((action == CRLF_BINARY) || !auto_crlf || !len)
return 0;
gather_stats(src, len, &stats);
if (action == CRLF_GUESS) {
/*
* We're currently not going to even try to convert stuff
* that has bare CR characters. Does anybody do that crazy
* stuff?
*/
if (stats.cr != stats.crlf)
return 0;
/*
* And add some heuristics for binary vs text, of course...
*/
if (is_binary(len, &stats))
return 0;
}
check_safe_crlf(path, action, &stats, checksafe);
/* Optimization: No CR? Nothing to convert, regardless. */
if (!stats.cr)
return 0;
/* only grow if not in place */
if (strbuf_avail(buf) + buf->len < len)
strbuf_grow(buf, len - buf->len);
dst = buf->buf;
if (action == CRLF_GUESS) {
/*
* If we guessed, we already know we rejected a file with
* lone CR, and we can strip a CR without looking at what
* follow it.
*/
do {
unsigned char c = *src++;
if (c != '\r')
*dst++ = c;
} while (--len);
} else {
do {
unsigned char c = *src++;
if (! (c == '\r' && (1 < len && *src == '\n')))
*dst++ = c;
} while (--len);
}
strbuf_setlen(buf, dst - buf->buf);
return 1;
}
static int crlf_to_worktree(const char *path, const char *src, size_t len,
struct strbuf *buf, int action)
{
char *to_free = NULL;
struct text_stat stats;
if ((action == CRLF_BINARY) || (action == CRLF_INPUT) ||
auto_crlf <= 0)
return 0;
if (!len)
return 0;
gather_stats(src, len, &stats);
/* No LF? Nothing to convert, regardless. */
if (!stats.lf)
return 0;
/* Was it already in CRLF format? */
if (stats.lf == stats.crlf)
return 0;
if (action == CRLF_GUESS) {
/* If we have any bare CR characters, we're not going to touch it */
if (stats.cr != stats.crlf)
return 0;
if (is_binary(len, &stats))
return 0;
}
/* are we "faking" in place editing ? */
if (src == buf->buf)
to_free = strbuf_detach(buf, NULL);
strbuf_grow(buf, len + stats.lf - stats.crlf);
for (;;) {
const char *nl = memchr(src, '\n', len);
if (!nl)
break;
if (nl > src && nl[-1] == '\r') {
strbuf_add(buf, src, nl + 1 - src);
} else {
strbuf_add(buf, src, nl - src);
strbuf_addstr(buf, "\r\n");
}
len -= nl + 1 - src;
src = nl + 1;
}
strbuf_add(buf, src, len);
free(to_free);
return 1;
}
struct filter_params {
const char *src;
unsigned long size;
const char *cmd;
};
static int filter_buffer(int fd, void *data)
{
/*
* Spawn cmd and feed the buffer contents through its stdin.
*/
struct child_process child_process;
struct filter_params *params = (struct filter_params *)data;
int write_err, status;
const char *argv[] = { "sh", "-c", params->cmd, NULL };
memset(&child_process, 0, sizeof(child_process));
child_process.argv = argv;
child_process.in = -1;
child_process.out = fd;
if (start_command(&child_process))
return error("cannot fork to run external filter %s", params->cmd);
write_err = (write_in_full(child_process.in, params->src, params->size) < 0);
if (close(child_process.in))
write_err = 1;
if (write_err)
error("cannot feed the input to external filter %s", params->cmd);
status = finish_command(&child_process);
if (status)
error("external filter %s failed %d", params->cmd, -status);
return (write_err || status);
}
static int apply_filter(const char *path, const char *src, size_t len,
struct strbuf *dst, const char *cmd)
{
/*
* Create a pipeline to have the command filter the buffer's
* contents.
*
* (child --> cmd) --> us
*/
int ret = 1;
struct strbuf nbuf = STRBUF_INIT;
struct async async;
struct filter_params params;
if (!cmd)
return 0;
memset(&async, 0, sizeof(async));
async.proc = filter_buffer;
async.data = &params;
params.src = src;
params.size = len;
params.cmd = cmd;
fflush(NULL);
if (start_async(&async))
return 0; /* error was already reported */
if (strbuf_read(&nbuf, async.out, len) < 0) {
error("read from external filter %s failed", cmd);
ret = 0;
}
if (close(async.out)) {
error("read from external filter %s failed", cmd);
ret = 0;
}
if (finish_async(&async)) {
error("external filter %s failed", cmd);
ret = 0;
}
if (ret) {
strbuf_swap(dst, &nbuf);
}
strbuf_release(&nbuf);
return ret;
}
static struct convert_driver {
const char *name;
struct convert_driver *next;
const char *smudge;
const char *clean;
} *user_convert, **user_convert_tail;
static int read_convert_config(const char *var, const char *value, void *cb)
{
const char *ep, *name;
int namelen;
struct convert_driver *drv;
/*
* External conversion drivers are configured using
* "filter.<name>.variable".
*/
if (prefixcmp(var, "filter.") || (ep = strrchr(var, '.')) == var + 6)
return 0;
name = var + 7;
namelen = ep - name;
for (drv = user_convert; drv; drv = drv->next)
if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
break;
if (!drv) {
drv = xcalloc(1, sizeof(struct convert_driver));
drv->name = xmemdupz(name, namelen);
*user_convert_tail = drv;
user_convert_tail = &(drv->next);
}
ep++;
/*
* filter.<name>.smudge and filter.<name>.clean specifies
* the command line:
*
* command-line
*
* The command-line will not be interpolated in any way.
*/
if (!strcmp("smudge", ep))
return git_config_string(&drv->smudge, var, value);
if (!strcmp("clean", ep))
return git_config_string(&drv->clean, var, value);
return 0;
}
static void setup_convert_check(struct git_attr_check *check)
{
static struct git_attr *attr_crlf;
static struct git_attr *attr_ident;
static struct git_attr *attr_filter;
if (!attr_crlf) {
attr_crlf = git_attr("crlf", 4);
attr_ident = git_attr("ident", 5);
attr_filter = git_attr("filter", 6);
user_convert_tail = &user_convert;
git_config(read_convert_config, NULL);
}
check[0].attr = attr_crlf;
check[1].attr = attr_ident;
check[2].attr = attr_filter;
}
static int count_ident(const char *cp, unsigned long size)
{
/*
* "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
*/
int cnt = 0;
char ch;
while (size) {
ch = *cp++;
size--;
if (ch != '$')
continue;
if (size < 3)
break;
if (memcmp("Id", cp, 2))
continue;
ch = cp[2];
cp += 3;
size -= 3;
if (ch == '$')
cnt++; /* $Id$ */
if (ch != ':')
continue;
/*
* "$Id: ... "; scan up to the closing dollar sign and discard.
*/
while (size) {
ch = *cp++;
size--;
if (ch == '$') {
cnt++;
break;
}
}
}
return cnt;
}
static int ident_to_git(const char *path, const char *src, size_t len,
struct strbuf *buf, int ident)
{
char *dst, *dollar;
if (!ident || !count_ident(src, len))
return 0;
/* only grow if not in place */
if (strbuf_avail(buf) + buf->len < len)
strbuf_grow(buf, len - buf->len);
dst = buf->buf;
for (;;) {
dollar = memchr(src, '$', len);
if (!dollar)
break;
memcpy(dst, src, dollar + 1 - src);
dst += dollar + 1 - src;
len -= dollar + 1 - src;
src = dollar + 1;
if (len > 3 && !memcmp(src, "Id:", 3)) {
dollar = memchr(src + 3, '$', len - 3);
if (!dollar)
break;
memcpy(dst, "Id$", 3);
dst += 3;
len -= dollar + 1 - src;
src = dollar + 1;
}
}
memcpy(dst, src, len);
strbuf_setlen(buf, dst + len - buf->buf);
return 1;
}
static int ident_to_worktree(const char *path, const char *src, size_t len,
struct strbuf *buf, int ident)
{
unsigned char sha1[20];
char *to_free = NULL, *dollar;
int cnt;
if (!ident)
return 0;
cnt = count_ident(src, len);
if (!cnt)
return 0;
/* are we "faking" in place editing ? */
if (src == buf->buf)
to_free = strbuf_detach(buf, NULL);
hash_sha1_file(src, len, "blob", sha1);
strbuf_grow(buf, len + cnt * 43);
for (;;) {
/* step 1: run to the next '$' */
dollar = memchr(src, '$', len);
if (!dollar)
break;
strbuf_add(buf, src, dollar + 1 - src);
len -= dollar + 1 - src;
src = dollar + 1;
/* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
if (len < 3 || memcmp("Id", src, 2))
continue;
/* step 3: skip over Id$ or Id:xxxxx$ */
if (src[2] == '$') {
src += 3;
len -= 3;
} else if (src[2] == ':') {
/*
* It's possible that an expanded Id has crept its way into the
* repository, we cope with that by stripping the expansion out
*/
dollar = memchr(src + 3, '$', len - 3);
if (!dollar) {
/* incomplete keyword, no more '$', so just quit the loop */
break;
}
len -= dollar + 1 - src;
src = dollar + 1;
} else {
/* it wasn't a "Id$" or "Id:xxxx$" */
continue;
}
/* step 4: substitute */
strbuf_addstr(buf, "Id: ");
strbuf_add(buf, sha1_to_hex(sha1), 40);
strbuf_addstr(buf, " $");
}
strbuf_add(buf, src, len);
free(to_free);
return 1;
}
static int git_path_check_crlf(const char *path, struct git_attr_check *check)
{
const char *value = check->value;
if (ATTR_TRUE(value))
return CRLF_TEXT;
else if (ATTR_FALSE(value))
return CRLF_BINARY;
else if (ATTR_UNSET(value))
;
else if (!strcmp(value, "input"))
return CRLF_INPUT;
return CRLF_GUESS;
}
static struct convert_driver *git_path_check_convert(const char *path,
struct git_attr_check *check)
{
const char *value = check->value;
struct convert_driver *drv;
if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
return NULL;
for (drv = user_convert; drv; drv = drv->next)
if (!strcmp(value, drv->name))
return drv;
return NULL;
}
static int git_path_check_ident(const char *path, struct git_attr_check *check)
{
const char *value = check->value;
return !!ATTR_TRUE(value);
}
int convert_to_git(const char *path, const char *src, size_t len,
struct strbuf *dst, enum safe_crlf checksafe)
{
struct git_attr_check check[3];
int crlf = CRLF_GUESS;
int ident = 0, ret = 0;
const char *filter = NULL;
setup_convert_check(check);
if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
struct convert_driver *drv;
crlf = git_path_check_crlf(path, check + 0);
ident = git_path_check_ident(path, check + 1);
drv = git_path_check_convert(path, check + 2);
if (drv && drv->clean)
filter = drv->clean;
}
ret |= apply_filter(path, src, len, dst, filter);
if (ret) {
src = dst->buf;
len = dst->len;
}
ret |= crlf_to_git(path, src, len, dst, crlf, checksafe);
if (ret) {
src = dst->buf;
len = dst->len;
}
return ret | ident_to_git(path, src, len, dst, ident);
}
int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
{
struct git_attr_check check[3];
int crlf = CRLF_GUESS;
int ident = 0, ret = 0;
const char *filter = NULL;
setup_convert_check(check);
if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
struct convert_driver *drv;
crlf = git_path_check_crlf(path, check + 0);
ident = git_path_check_ident(path, check + 1);
drv = git_path_check_convert(path, check + 2);
if (drv && drv->smudge)
filter = drv->smudge;
}
ret |= ident_to_worktree(path, src, len, dst, ident);
if (ret) {
src = dst->buf;
len = dst->len;
}
ret |= crlf_to_worktree(path, src, len, dst, crlf);
if (ret) {
src = dst->buf;
len = dst->len;
}
return ret | apply_filter(path, src, len, dst, filter);
}