95f5c52e6
Roman Borisov
2011-03-27
Subject
diff: optimize diffing of files with the same metadata
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editors/diff.c+25 -0
| @@ -952,6 +952,31 @@ int diff_main(int argc UNUSED_PARAM, char **argv) | |
| if (gotstdin && (S_ISDIR(stb[0].st_mode) || S_ISDIR(stb[1].st_mode))) | |
| bb_error_msg_and_die("can't compare stdin to a directory"); | |
| + | /* Compare metadata to check if the files are the same physical file. |
| + | * |
| + | * Comment from diffutils source says: |
| + | * POSIX says that two files are identical if st_ino and st_dev are |
| + | * the same, but many file systems incorrectly assign the same (device, |
| + | * inode) pair to two distinct files, including: |
| + | * GNU/Linux NFS servers that export all local file systems as a |
| + | * single NFS file system, if a local device number (st_dev) exceeds |
| + | * 255, or if a local inode number (st_ino) exceeds 16777215. |
| + | */ |
| + | if (ENABLE_DESKTOP |
| + | && stb[0].st_ino == stb[1].st_ino |
| + | && stb[0].st_dev == stb[1].st_dev |
| + | && stb[0].st_size == stb[1].st_size |
| + | && stb[0].st_mtime == stb[1].st_mtime |
| + | && stb[0].st_ctime == stb[1].st_ctime |
| + | && stb[0].st_mode == stb[1].st_mode |
| + | && stb[0].st_nlink == stb[1].st_nlink |
| + | && stb[0].st_uid == stb[1].st_uid |
| + | && stb[0].st_gid == stb[1].st_gid |
| + | ) { |
| + | /* files are physically the same; no need to compare them */ |
| + | return STATUS_SAME; |
| + | } |
| + | |
| if (S_ISDIR(stb[0].st_mode) && S_ISDIR(stb[1].st_mode)) { | |
| #if ENABLE_FEATURE_DIFF_DIR | |
| diffdir(file, s_start); | |