teach convert_to_git a "dry run" mode

diff --git a/csum-file.c b/csum-file.c
index be49d5fcf900cb47cb14d8c85a69112b26532b93..fc97d6e04528b5c5b55fc211a462f3cb828f3d49 100644 (file)
--- a/csum-file.c
+++ b/csum-file.c
@@ -11,8 +11,20 @@
 #include "progress.h"
 #include "csum-file.h"
 
-static void flush(struct sha1file *f, void * buf, unsigned int count)
+static void flush(struct sha1file *f, void *buf, unsigned int count)
 {
+       if (0 <= f->check_fd && count)  {
+               unsigned char check_buffer[8192];
+               ssize_t ret = read_in_full(f->check_fd, check_buffer, count);
+
+               if (ret < 0)
+                       die_errno("%s: sha1 file read error", f->name);
+               if (ret < count)
+                       die("%s: sha1 file truncated", f->name);
+               if (memcmp(buf, check_buffer, count))
+                       die("sha1 file '%s' validation error", f->name);
+       }
+
        for (;;) {
                int ret = xwrite(f->fd, buf, count);
                if (ret > 0) {
@@ -59,6 +71,17 @@ int sha1close(struct sha1file *f, unsigned char *result, unsigned int flags)
                fd = 0;
        } else
                fd = f->fd;
+       if (0 <= f->check_fd) {
+               char discard;
+               int cnt = read_in_full(f->check_fd, &discard, 1);
+               if (cnt < 0)
+                       die_errno("%s: error when reading the tail of sha1 file",
+                                 f->name);
+               if (cnt)
+                       die("%s: sha1 file has trailing garbage", f->name);
+               if (close(f->check_fd))
+                       die_errno("%s: sha1 file error on close", f->name);
+       }
        free(f);
        return fd;
 }
@@ -101,10 +124,31 @@ struct sha1file *sha1fd(int fd, const char *name)
        return sha1fd_throughput(fd, name, NULL);
 }
 
+struct sha1file *sha1fd_check(const char *name)
+{
+       int sink, check;
+       struct sha1file *f;
+
+       sink = open("/dev/null", O_WRONLY);
+       if (sink < 0)
+               return NULL;
+       check = open(name, O_RDONLY);
+       if (check < 0) {
+               int saved_errno = errno;
+               close(sink);
+               errno = saved_errno;
+               return NULL;
+       }
+       f = sha1fd(sink, name);
+       f->check_fd = check;
+       return f;
+}
+
 struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp)
 {
        struct sha1file *f = xmalloc(sizeof(*f));
        f->fd = fd;
+       f->check_fd = -1;
        f->offset = 0;
        f->total = 0;
        f->tp = tp;