Rewrite convert_to_{git,working_tree} to use strbuf's.
[git/git.git] / convert.c
index d77c8eb..00a341c 100644 (file)
--- a/convert.c
+++ b/convert.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "attr.h"
 #include "run-command.h"
+#include "strbuf.h"
 
 /*
  * convert.c - convert a file when checking it out and checking it in.
@@ -80,24 +81,19 @@ static int is_binary(unsigned long size, struct text_stat *stats)
        return 0;
 }
 
-static char *crlf_to_git(const char *path, const char *src, unsigned long *sizep, int action)
+static int crlf_to_git(const char *path, const char *src, size_t len,
+                       struct strbuf *buf, int action)
 {
-       char *buffer, *dst;
-       unsigned long size, nsize;
        struct text_stat stats;
+       char *dst;
 
-       if ((action == CRLF_BINARY) || !auto_crlf)
-               return NULL;
-
-       size = *sizep;
-       if (!size)
-               return NULL;
-
-       gather_stats(src, size, &stats);
+       if ((action == CRLF_BINARY) || !auto_crlf || !len)
+               return 0;
 
+       gather_stats(src, len, &stats);
        /* No CR? Nothing to convert, regardless. */
        if (!stats.cr)
-               return NULL;
+               return 0;
 
        if (action == CRLF_GUESS) {
                /*
@@ -106,24 +102,17 @@ static char *crlf_to_git(const char *path, const char *src, unsigned long *sizep
                 * stuff?
                 */
                if (stats.cr != stats.crlf)
-                       return NULL;
+                       return 0;
 
                /*
                 * And add some heuristics for binary vs text, of course...
                 */
-               if (is_binary(size, &stats))
-                       return NULL;
+               if (is_binary(len, &stats))
+                       return 0;
        }
 
-       /*
-        * 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;
+       strbuf_grow(buf, len);
+       dst = buf->buf;
        if (action == CRLF_GUESS) {
                /*
                 * If we guessed, we already know we rejected a file with
@@ -134,71 +123,72 @@ static char *crlf_to_git(const char *path, const char *src, unsigned long *sizep
                        unsigned char c = *src++;
                        if (c != '\r')
                                *dst++ = c;
-               } while (--size);
+               } while (--len);
        } else {
                do {
                        unsigned char c = *src++;
-                       if (! (c == '\r' && (1 < size && *src == '\n')))
+                       if (! (c == '\r' && (1 < len && *src == '\n')))
                                *dst++ = c;
-               } while (--size);
+               } while (--len);
        }
-
-       return buffer;
+       strbuf_setlen(buf, dst - buf->buf);
+       return 1;
 }
 
-static char *crlf_to_worktree(const char *path, const char *src, unsigned long *sizep, int action)
+static int crlf_to_worktree(const char *path, const char *src, size_t len,
+                            struct strbuf *buf, int action)
 {
-       char *buffer, *dst;
-       unsigned long size, nsize;
+       char *to_free = NULL;
        struct text_stat stats;
-       unsigned char last;
 
        if ((action == CRLF_BINARY) || (action == CRLF_INPUT) ||
            auto_crlf <= 0)
-               return NULL;
+               return 0;
 
-       size = *sizep;
-       if (!size)
-               return NULL;
+       if (!len)
+               return 0;
 
-       gather_stats(src, size, &stats);
+       gather_stats(src, len, &stats);
 
        /* No LF? Nothing to convert, regardless. */
        if (!stats.lf)
-               return NULL;
+               return 0;
 
        /* Was it already in CRLF format? */
        if (stats.lf == stats.crlf)
-               return NULL;
+               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 NULL;
+                       return 0;
 
-               if (is_binary(size, &stats))
-                       return NULL;
+               if (is_binary(len, &stats))
+                       return 0;
        }
 
-       /*
-        * 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;
+       /* are we "faking" in place editing ? */
+       if (src == buf->buf)
+               to_free = strbuf_detach(buf);
+
+       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;
 }
 
 static int filter_buffer(const char *path, const char *src,
@@ -246,8 +236,8 @@ static int filter_buffer(const char *path, const char *src,
        return (write_err || status);
 }
 
-static char *apply_filter(const char *path, const char *src,
-                         unsigned long *sizep, const char *cmd)
+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
@@ -255,21 +245,19 @@ static char *apply_filter(const char *path, const char *src,
         *
         * (child --> cmd) --> us
         */
-       const int SLOP = 4096;
        int pipe_feed[2];
-       int status;
-       char *dst;
-       unsigned long dstsize, dstalloc;
+       int status, ret = 1;
        struct child_process child_process;
+       struct strbuf nbuf;
 
        if (!cmd)
-               return NULL;
+               return 0;
 
        memset(&child_process, 0, sizeof(child_process));
 
        if (pipe(pipe_feed) < 0) {
                error("cannot create pipe to run external filter %s", cmd);
-               return NULL;
+               return 0;
        }
 
        fflush(NULL);
@@ -278,54 +266,37 @@ static char *apply_filter(const char *path, const char *src,
                error("cannot fork to run external filter %s", cmd);
                close(pipe_feed[0]);
                close(pipe_feed[1]);
-               return NULL;
+               return 0;
        }
        if (!child_process.pid) {
                dup2(pipe_feed[1], 1);
                close(pipe_feed[0]);
                close(pipe_feed[1]);
-               exit(filter_buffer(path, src, *sizep, cmd));
+               exit(filter_buffer(path, src, len, 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);
-               }
+       strbuf_init(&nbuf, 0);
+       if (strbuf_read(&nbuf, pipe_feed[0], len) < 0) {
+               error("read from external filter %s failed", cmd);
+               ret = 0;
        }
        if (close(pipe_feed[0])) {
-               error("read from external filter %s failed", cmd);
-               free(dst);
-               dst = NULL;
+               ret = error("read from external filter %s failed", cmd);
+               ret = 0;
        }
-
        status = finish_command(&child_process);
        if (status) {
-               error("external filter %s failed %d", cmd, -status);
-               free(dst);
-               dst = NULL;
+               ret = error("external filter %s failed %d", cmd, -status);
+               ret = 0;
        }
 
-       if (dst)
-               *sizep = dstsize;
-       return dst;
+       if (ret) {
+               *dst = nbuf;
+       } else {
+               strbuf_release(&nbuf);
+       }
+       return ret;
 }
 
 static struct convert_driver {
@@ -449,137 +420,104 @@ static int count_ident(const char *cp, unsigned long size)
        return cnt;
 }
 
-static char *ident_to_git(const char *path, const char *src, unsigned long *sizep, int ident)
+static int ident_to_git(const char *path, const char *src, size_t len,
+                        struct strbuf *buf, int ident)
 {
-       int cnt;
-       unsigned long size;
-       char *dst, *buf;
+       char *dst, *dollar;
 
-       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;
+       if (!ident || !count_ident(src, len))
+               return 0;
+
+       strbuf_grow(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;
-                       size -= (cp - src);
-                       src = cp;
+                       len -= dollar + 1 - src;
+                       src  = dollar + 1;
                }
        }
-
-       *sizep = dst - buf;
-       return buf;
+       memcpy(dst, src, len);
+       strbuf_setlen(buf, dst + len - buf->buf);
+       return 1;
 }
 
-static char *ident_to_worktree(const char *path, const char *src, unsigned long *sizep, int ident)
+static int ident_to_worktree(const char *path, const char *src, size_t len,
+                             struct strbuf *buf, int ident)
 {
-       int cnt;
-       unsigned long size;
-       char *dst, *buf;
        unsigned char sha1[20];
+       char *to_free = NULL, *dollar;
+       int cnt;
 
        if (!ident)
-               return NULL;
+               return 0;
 
-       size = *sizep;
-       cnt = count_ident(src, size);
+       cnt = count_ident(src, len);
        if (!cnt)
-               return NULL;
+               return 0;
 
-       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"
-                */
+       /* are we "faking" in place editing ? */
+       if (src == buf->buf)
+               to_free = strbuf_detach(buf);
+       hash_sha1_file(src, len, "blob", sha1);
 
-               /*
-                * 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 "$Id:" at the front */
+       strbuf_grow(buf, len + cnt * 43);
+       for (;;) {
+               /* step 1: run to the next '$' */
+               dollar = memchr(src, '$', len);
+               if (!dollar)
+                       break;
+               strbuf_add(buf, src, dollar + 1 - src);
+               len -= dollar + 1 - src;
+               src  = dollar + 1;
 
-                       /* 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 */
+               /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
+               if (len < 3 || memcmp("Id", src, 2))
                        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++ = ' ';
+               /* 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;
+                       }
 
-               /* Adjust for the characters we've discarded */
-               size -= (cp - src);
-               src = cp;
+                       len -= dollar + 1 - src;
+                       src  = dollar + 1;
+               } else {
+                       /* it wasn't a "Id$" or "Id:xxxx$" */
+                       continue;
+               }
 
-               /* Copy the final "$" */
-               *dst++ = *src++;
-               size--;
+               /* step 4: substitute */
+               strbuf_addstr(buf, "Id: ");
+               strbuf_add(buf, sha1_to_hex(sha1), 40);
+               strbuf_addstr(buf, " $");
        }
+       strbuf_add(buf, src, len);
 
-       *sizep = dst - buf;
-       return buf;
+       free(to_free);
+       return 1;
 }
 
 static int git_path_check_crlf(const char *path, struct git_attr_check *check)
@@ -618,13 +556,12 @@ static int git_path_check_ident(const char *path, struct git_attr_check *check)
        return !!ATTR_TRUE(value);
 }
 
-char *convert_to_git(const char *path, const char *src, unsigned long *sizep)
+int convert_to_git(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;
+       int ident = 0, ret = 0;
        char *filter = NULL;
-       char *buf, *buf2;
 
        setup_convert_check(check);
        if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
@@ -636,30 +573,25 @@ char *convert_to_git(const char *path, const char *src, unsigned long *sizep)
                        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;
+       ret |= apply_filter(path, src, len, dst, filter);
+       if (ret) {
+               src = dst->buf;
+               len = dst->len;
        }
-
-       buf2 = ident_to_git(path, buf ? buf : src, sizep, ident);
-       if (buf2) {
-               free(buf);
-               buf = buf2;
+       ret |= crlf_to_git(path, src, len, dst, crlf);
+       if (ret) {
+               src = dst->buf;
+               len = dst->len;
        }
-
-       return buf;
+       return ret | ident_to_git(path, src, len, dst, ident);
 }
 
-char *convert_to_working_tree(const char *path, const char *src, unsigned long *sizep)
+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;
+       int ident = 0, ret = 0;
        char *filter = NULL;
-       char *buf, *buf2;
 
        setup_convert_check(check);
        if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
@@ -671,19 +603,15 @@ char *convert_to_working_tree(const char *path, const char *src, unsigned long *
                        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;
+       ret |= ident_to_worktree(path, src, len, dst, ident);
+       if (ret) {
+               src = dst->buf;
+               len = dst->len;
        }
-
-       buf2 = apply_filter(path, buf ? buf : src, sizep, filter);
-       if (buf2) {
-               free(buf);
-               buf = buf2;
+       ret |= crlf_to_worktree(path, src, len, dst, crlf);
+       if (ret) {
+               src = dst->buf;
+               len = dst->len;
        }
-
-       return buf;
+       return ret | apply_filter(path, src, len, dst, filter);
 }