[PATCH] Fix broken diff-cache output on added files

[git.git] / sha1_file.c

diff --git a/sha1_file.c b/sha1_file.c
index 40c00b7..66308ed 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -11,6 +11,16 @@
 
 const char *sha1_file_directory = NULL;
 
+#ifndef O_NOATIME
+#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
+#define O_NOATIME 01000000
+#else
+#define O_NOATIME 0
+#endif
+#endif
+
+static unsigned int sha1_file_open_flag = O_NOATIME;
+
 static unsigned hexval(char c)
 {
        if (c >= '0' && c <= '9')
@@ -96,13 +106,26 @@ int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, con
 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 {
        char *filename = sha1_file_name(sha1);
-       int fd = open(filename, O_RDONLY);
        struct stat st;
        void *map;
+       int fd;
 
+       fd = open(filename, O_RDONLY | sha1_file_open_flag);
        if (fd < 0) {
-               perror(filename);
-               return NULL;
+               /* See if it works without O_NOATIME */
+               switch (sha1_file_open_flag) {
+               default:
+                       fd = open(filename, O_RDONLY);
+                       if (fd >= 0)
+                               break;
+               /* Fallthrough */
+               case 0:
+                       perror(filename);
+                       return NULL;
+               }
+
+               /* If it failed once, it will probably fail again. Stop using O_NOATIME */
+               sha1_file_open_flag = 0;
        }
        if (fstat(fd, &st) < 0) {
                close(fd);
@@ -166,6 +189,46 @@ void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size
        return NULL;
 }
 
+void *read_tree_with_tree_or_commit_sha1(const unsigned char *sha1,
+                                        unsigned long *size,
+                                        unsigned char *tree_sha1_return)
+{
+       char type[20];
+       void *buffer;
+       unsigned long isize;
+       int was_commit = 0;
+       unsigned char tree_sha1[20];
+
+       buffer = read_sha1_file(sha1, type, &isize);
+
+       /* 
+        * We might have read a commit instead of a tree, in which case
+        * we parse out the tree_sha1 and attempt to read from there.
+        * (buffer + 5) is because the tree sha1 is always at offset 5
+        * in a commit record ("tree ").
+        */
+       if (buffer &&
+           !strcmp(type, "commit") &&
+           !get_sha1_hex(buffer + 5, tree_sha1)) {
+               free(buffer);
+               buffer = read_sha1_file(tree_sha1, type, &isize);
+               was_commit = 1;
+       }
+
+       /*
+        * Now do we have something and if so is it a tree?
+        */
+       if (!buffer || strcmp(type, "tree")) {
+               free(buffer);
+               return NULL;
+       }
+
+       *size = isize;
+       if (tree_sha1_return)
+               memcpy(tree_sha1_return, was_commit ? tree_sha1 : sha1, 20);
+       return buffer;
+}
+
 int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
 {
        int size;
@@ -173,12 +236,30 @@ int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
        z_stream stream;
        unsigned char sha1[20];
        SHA_CTX c;
+       char *filename;
+       int fd;
 
        /* Sha1.. */
        SHA1_Init(&c);
        SHA1_Update(&c, buf, len);
        SHA1_Final(sha1, &c);
 
+       if (returnsha1)
+               memcpy(returnsha1, sha1, 20);
+
+       filename = sha1_file_name(sha1);
+       fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
+       if (fd < 0) {
+               if (errno != EEXIST)
+                       return -1;
+
+               /*
+                * We might do collision checking here, but we'd need to
+                * uncompress the old file and check it. Later.
+                */
+               return 0;
+       }
+
        /* Set it up */
        memset(&stream, 0, sizeof(stream));
        deflateInit(&stream, Z_BEST_COMPRESSION);
@@ -195,10 +276,10 @@ int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
        deflateEnd(&stream);
        size = stream.total_out;
 
-       if (write_sha1_buffer(sha1, compressed, size) < 0)
-               return -1;
-       if (returnsha1)
-               memcpy(returnsha1, sha1, 20);
+       if (write(fd, compressed, size) != size)
+               die("unable to write file");
+       close(fd);
+               
        return 0;
 }