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-rw-r--r--convert.c704
1 files changed, 704 insertions, 0 deletions
diff --git a/convert.c b/convert.c
new file mode 100644
index 0000000000..21908b1039
--- /dev/null
+++ b/convert.c
@@ -0,0 +1,704 @@
+#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 {
+ /* CR, LF and CRLF counts */
+ unsigned 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;
+ default:
+ stats->nonprintable++;
+ }
+ }
+ else
+ stats->printable++;
+ }
+}
+
+/*
+ * The same heuristics as diff.c::mmfile_is_binary()
+ */
+static int is_binary(unsigned long size, struct text_stat *stats)
+{
+
+ 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 char *crlf_to_git(const char *path, const char *src, unsigned long *sizep, int action)
+{
+ char *buffer, *dst;
+ unsigned long size, nsize;
+ struct text_stat stats;
+
+ if ((action == CRLF_BINARY) || !auto_crlf)
+ return NULL;
+
+ size = *sizep;
+ if (!size)
+ return NULL;
+
+ gather_stats(src, size, &stats);
+
+ /* No CR? Nothing to convert, regardless. */
+ if (!stats.cr)
+ return NULL;
+
+ 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 NULL;
+
+ /*
+ * And add some heuristics for binary vs text, of course...
+ */
+ if (is_binary(size, &stats))
+ return NULL;
+ }
+
+ /*
+ * Ok, allocate a new buffer, fill it in, and return it
+ * to let the caller know that we switched buffers.
+ */
+ nsize = size - stats.crlf;
+ buffer = xmalloc(nsize);
+ *sizep = nsize;
+
+ dst = buffer;
+ 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 (--size);
+ } else {
+ do {
+ unsigned char c = *src++;
+ if (! (c == '\r' && (1 < size && *src == '\n')))
+ *dst++ = c;
+ } while (--size);
+ }
+
+ return buffer;
+}
+
+static char *crlf_to_worktree(const char *path, const char *src, unsigned long *sizep, int action)
+{
+ char *buffer, *dst;
+ unsigned long size, nsize;
+ struct text_stat stats;
+ unsigned char last;
+
+ if ((action == CRLF_BINARY) || (action == CRLF_INPUT) ||
+ auto_crlf <= 0)
+ return NULL;
+
+ size = *sizep;
+ if (!size)
+ return NULL;
+
+ gather_stats(src, size, &stats);
+
+ /* No LF? Nothing to convert, regardless. */
+ if (!stats.lf)
+ return NULL;
+
+ /* Was it already in CRLF format? */
+ if (stats.lf == stats.crlf)
+ return NULL;
+
+ if (action == CRLF_GUESS) {
+ /* If we have any bare CR characters, we're not going to touch it */
+ if (stats.cr != stats.crlf)
+ return NULL;
+
+ if (is_binary(size, &stats))
+ return NULL;
+ }
+
+ /*
+ * Ok, allocate a new buffer, fill it in, and return it
+ * to let the caller know that we switched buffers.
+ */
+ nsize = size + stats.lf - stats.crlf;
+ buffer = xmalloc(nsize);
+ *sizep = nsize;
+ last = 0;
+
+ dst = buffer;
+ do {
+ unsigned char c = *src++;
+ if (c == '\n' && last != '\r')
+ *dst++ = '\r';
+ *dst++ = c;
+ last = c;
+ } while (--size);
+
+ return buffer;
+}
+
+static int filter_buffer(const char *path, const char *src,
+ unsigned long size, const char *cmd)
+{
+ /*
+ * Spawn cmd and feed the buffer contents through its stdin.
+ */
+ struct child_process child_process;
+ int pipe_feed[2];
+ int write_err, status;
+
+ memset(&child_process, 0, sizeof(child_process));
+
+ if (pipe(pipe_feed) < 0) {
+ error("cannot create pipe to run external filter %s", cmd);
+ return 1;
+ }
+
+ child_process.pid = fork();
+ if (child_process.pid < 0) {
+ error("cannot fork to run external filter %s", cmd);
+ close(pipe_feed[0]);
+ close(pipe_feed[1]);
+ return 1;
+ }
+ if (!child_process.pid) {
+ dup2(pipe_feed[0], 0);
+ close(pipe_feed[0]);
+ close(pipe_feed[1]);
+ execlp("sh", "sh", "-c", cmd, NULL);
+ return 1;
+ }
+ close(pipe_feed[0]);
+
+ write_err = (write_in_full(pipe_feed[1], src, size) < 0);
+ if (close(pipe_feed[1]))
+ write_err = 1;
+ if (write_err)
+ error("cannot feed the input to external filter %s", cmd);
+
+ status = finish_command(&child_process);
+ if (status)
+ error("external filter %s failed %d", cmd, -status);
+ return (write_err || status);
+}
+
+static char *apply_filter(const char *path, const char *src,
+ unsigned long *sizep, const char *cmd)
+{
+ /*
+ * Create a pipeline to have the command filter the buffer's
+ * contents.
+ *
+ * (child --> cmd) --> us
+ */
+ const int SLOP = 4096;
+ int pipe_feed[2];
+ int status;
+ char *dst;
+ unsigned long dstsize, dstalloc;
+ struct child_process child_process;
+
+ if (!cmd)
+ return NULL;
+
+ memset(&child_process, 0, sizeof(child_process));
+
+ if (pipe(pipe_feed) < 0) {
+ error("cannot create pipe to run external filter %s", cmd);
+ return NULL;
+ }
+
+ fflush(NULL);
+ child_process.pid = fork();
+ if (child_process.pid < 0) {
+ error("cannot fork to run external filter %s", cmd);
+ close(pipe_feed[0]);
+ close(pipe_feed[1]);
+ return NULL;
+ }
+ if (!child_process.pid) {
+ dup2(pipe_feed[1], 1);
+ close(pipe_feed[0]);
+ close(pipe_feed[1]);
+ exit(filter_buffer(path, src, *sizep, cmd));
+ }
+ close(pipe_feed[1]);
+
+ dstalloc = *sizep;
+ dst = xmalloc(dstalloc);
+ dstsize = 0;
+
+ while (1) {
+ ssize_t numread = xread(pipe_feed[0], dst + dstsize,
+ dstalloc - dstsize);
+
+ if (numread <= 0) {
+ if (!numread)
+ break;
+ error("read from external filter %s failed", cmd);
+ free(dst);
+ dst = NULL;
+ break;
+ }
+ dstsize += numread;
+ if (dstalloc <= dstsize + SLOP) {
+ dstalloc = dstsize + SLOP;
+ dst = xrealloc(dst, dstalloc);
+ }
+ }
+ if (close(pipe_feed[0])) {
+ error("read from external filter %s failed", cmd);
+ free(dst);
+ dst = NULL;
+ }
+
+ status = finish_command(&child_process);
+ if (status) {
+ error("external filter %s failed %d", cmd, -status);
+ free(dst);
+ dst = NULL;
+ }
+
+ if (dst)
+ *sizep = dstsize;
+ return dst;
+}
+
+static struct convert_driver {
+ const char *name;
+ struct convert_driver *next;
+ char *smudge;
+ char *clean;
+} *user_convert, **user_convert_tail;
+
+static int read_convert_config(const char *var, const char *value)
+{
+ 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) {
+ char *namebuf;
+ drv = xcalloc(1, sizeof(struct convert_driver));
+ namebuf = xmalloc(namelen + 1);
+ memcpy(namebuf, name, namelen);
+ namebuf[namelen] = 0;
+ drv->name = namebuf;
+ drv->next = NULL;
+ *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)) {
+ if (!value)
+ return error("%s: lacks value", var);
+ drv->smudge = strdup(value);
+ return 0;
+ }
+
+ if (!strcmp("clean", ep)) {
+ if (!value)
+ return error("%s: lacks value", var);
+ drv->clean = strdup(value);
+ return 0;
+ }
+ 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);
+ }
+ 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 char *ident_to_git(const char *path, const char *src, unsigned long *sizep, int ident)
+{
+ int cnt;
+ unsigned long size;
+ char *dst, *buf;
+
+ if (!ident)
+ return NULL;
+ size = *sizep;
+ cnt = count_ident(src, size);
+ if (!cnt)
+ return NULL;
+ buf = xmalloc(size);
+
+ for (dst = buf; size; size--) {
+ char ch = *src++;
+ *dst++ = ch;
+ if ((ch == '$') && (3 <= size) &&
+ !memcmp("Id:", src, 3)) {
+ unsigned long rem = size - 3;
+ const char *cp = src + 3;
+ do {
+ ch = *cp++;
+ if (ch == '$')
+ break;
+ rem--;
+ } while (rem);
+ if (!rem)
+ continue;
+ memcpy(dst, "Id$", 3);
+ dst += 3;
+ size -= (cp - src);
+ src = cp;
+ }
+ }
+
+ *sizep = dst - buf;
+ return buf;
+}
+
+static char *ident_to_worktree(const char *path, const char *src, unsigned long *sizep, int ident)
+{
+ int cnt;
+ unsigned long size;
+ char *dst, *buf;
+ unsigned char sha1[20];
+
+ if (!ident)
+ return NULL;
+
+ size = *sizep;
+ cnt = count_ident(src, size);
+ if (!cnt)
+ return NULL;
+
+ hash_sha1_file(src, size, "blob", sha1);
+ buf = xmalloc(size + cnt * 43);
+
+ for (dst = buf; size; size--) {
+ const char *cp;
+ /* Fetch next source character, move the pointer on */
+ char ch = *src++;
+ /* Copy the current character to the destination */
+ *dst++ = ch;
+ /* If the current character is "$" or there are less than three
+ * remaining bytes or the two bytes following this one are not
+ * "Id", then simply read the next character */
+ if ((ch != '$') || (size < 3) || memcmp("Id", src, 2))
+ continue;
+ /*
+ * Here when
+ * - There are more than 2 bytes remaining
+ * - The current three bytes are "$Id"
+ * with
+ * - ch == "$"
+ * - src[0] == "I"
+ */
+
+ /*
+ * It's possible that an expanded Id has crept its way into the
+ * repository, we cope with that by stripping the expansion out
+ */
+ if (src[2] == ':') {
+ /* Expanded keywords have "$Id:" at the front */
+
+ /* discard up to but not including the closing $ */
+ unsigned long rem = size - 3;
+ /* Point at first byte after the ":" */
+ cp = src + 3;
+ /*
+ * Throw away characters until either
+ * - we reach a "$"
+ * - we run out of bytes (rem == 0)
+ */
+ do {
+ ch = *cp;
+ if (ch == '$')
+ break;
+ cp++;
+ rem--;
+ } while (rem);
+ /* If the above finished because it ran out of characters, then
+ * this is an incomplete keyword, so don't run the expansion */
+ if (!rem)
+ continue;
+ } else if (src[2] == '$')
+ cp = src + 2;
+ else
+ /* Anything other than "$Id:XXX$" or $Id$ and we skip the
+ * expansion */
+ continue;
+
+ /* cp is now pointing at the last $ of the keyword */
+
+ memcpy(dst, "Id: ", 4);
+ dst += 4;
+ memcpy(dst, sha1_to_hex(sha1), 40);
+ dst += 40;
+ *dst++ = ' ';
+
+ /* Adjust for the characters we've discarded */
+ size -= (cp - src);
+ src = cp;
+
+ /* Copy the final "$" */
+ *dst++ = *src++;
+ size--;
+ }
+
+ *sizep = dst - buf;
+ return buf;
+}
+
+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);
+}
+
+char *convert_to_git(const char *path, const char *src, unsigned long *sizep)
+{
+ struct git_attr_check check[3];
+ int crlf = CRLF_GUESS;
+ int ident = 0;
+ char *filter = NULL;
+ char *buf, *buf2;
+
+ 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;
+ }
+
+ buf = apply_filter(path, src, sizep, filter);
+
+ buf2 = crlf_to_git(path, buf ? buf : src, sizep, crlf);
+ if (buf2) {
+ free(buf);
+ buf = buf2;
+ }
+
+ buf2 = ident_to_git(path, buf ? buf : src, sizep, ident);
+ if (buf2) {
+ free(buf);
+ buf = buf2;
+ }
+
+ return buf;
+}
+
+char *convert_to_working_tree(const char *path, const char *src, unsigned long *sizep)
+{
+ struct git_attr_check check[3];
+ int crlf = CRLF_GUESS;
+ int ident = 0;
+ char *filter = NULL;
+ char *buf, *buf2;
+
+ 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;
+ }
+
+ buf = ident_to_worktree(path, src, sizep, ident);
+
+ buf2 = crlf_to_worktree(path, buf ? buf : src, sizep, crlf);
+ if (buf2) {
+ free(buf);
+ buf = buf2;
+ }
+
+ buf2 = apply_filter(path, buf ? buf : src, sizep, filter);
+ if (buf2) {
+ free(buf);
+ buf = buf2;
+ }
+
+ return buf;
+}
+
+void *convert_sha1_file(const char *path, const unsigned char *sha1,
+ unsigned int mode, enum object_type *type,
+ unsigned long *size)
+{
+ void *buffer = read_sha1_file(sha1, type, size);
+ if (S_ISREG(mode) && buffer) {
+ void *converted = convert_to_working_tree(path, buffer, size);
+ if (converted) {
+ free(buffer);
+ buffer = converted;
+ }
+ }
+ return buffer;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-18 11:01:04 +0000