contrib: add 'git difftool' for launching common merge tools

[git.git] / strbuf.c

diff --git a/strbuf.c b/strbuf.c
index 13be67e4d3e38472adbff019a34e3f5ce9621dd7..6ed06840b856a91f6d215c9a862e064f521384f0 100644 (file)
--- a/strbuf.c
+++ b/strbuf.c
@@ -256,18 +256,21 @@ size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder,
 size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f)
 {
        size_t res;
+       size_t oldalloc = sb->alloc;
 
        strbuf_grow(sb, size);
        res = fread(sb->buf + sb->len, 1, size, f);
-       if (res > 0) {
+       if (res > 0)
                strbuf_setlen(sb, sb->len + res);
-       }
+       else if (res < 0 && oldalloc == 0)
+               strbuf_release(sb);
        return res;
 }
 
 ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint)
 {
        size_t oldlen = sb->len;
+       size_t oldalloc = sb->alloc;
 
        strbuf_grow(sb, hint ? hint : 8192);
        for (;;) {
@@ -275,7 +278,10 @@ ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint)
 
                cnt = xread(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
                if (cnt < 0) {
-                       strbuf_setlen(sb, oldlen);
+                       if (oldalloc == 0)
+                               strbuf_release(sb);
+                       else
+                               strbuf_setlen(sb, oldlen);
                        return -1;
                }
                if (!cnt)
@@ -288,6 +294,36 @@ ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint)
        return sb->len - oldlen;
 }
 
+#define STRBUF_MAXLINK (2*PATH_MAX)
+
+int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
+{
+       size_t oldalloc = sb->alloc;
+
+       if (hint < 32)
+               hint = 32;
+
+       while (hint < STRBUF_MAXLINK) {
+               int len;
+
+               strbuf_grow(sb, hint);
+               len = readlink(path, sb->buf, hint);
+               if (len < 0) {
+                       if (errno != ERANGE)
+                               break;
+               } else if (len < hint) {
+                       strbuf_setlen(sb, len);
+                       return 0;
+               }
+
+               /* .. the buffer was too small - try again */
+               hint *= 2;
+       }
+       if (oldalloc == 0)
+               strbuf_release(sb);
+       return -1;
+}
+
 int strbuf_getline(struct strbuf *sb, FILE *fp, int term)
 {
        int ch;