Support index writing.

[jelmer/dulwich-libgit2.git] / dulwich / index.py

diff --git a/dulwich/index.py b/dulwich/index.py
index c06f9d33342fb0114faba088fed8baa6368f6259..3349cd66092ca61079cd2f7df3110e0d6aa47847 100644 (file)
--- a/dulwich/index.py
+++ b/dulwich/index.py
@@ -23,6 +23,8 @@ import struct
 def read_cache_time(f):
     return struct.unpack(">LL", f.read(8))
 
+def write_cache_time(f, t):
+    f.write(struct.pack(">LL", *t))
 
 def read_cache_entry(f):
     beginoffset = f.tell()
@@ -40,25 +42,55 @@ def read_cache_entry(f):
     f.seek(beginoffset + real_size)
     return (name, ctime, mtime, ino, dev, mode, uid, gid, size, sha, flags)
 
+
+def write_cache_entry(f, entry):
+    beginoffset = f.tell()
+    (name, ctime, mtime, ino, dev, mode, uid, gid, size, sha, flags) = entry
+    write_cache_time(f, ctime)
+    write_cache_time(f, mtime)
+    f.write(struct.pack(">LLLLLL20sH", ino, dev, mode, uid, gid, size, sha, flags))
+    f.write(name)
+    f.write(chr(0))
+    real_size = ((f.tell() - beginoffset + 8) & ~7)
+    f.write(chr(0) * (f.tell() - (beginoffset + real_size)))
+    return 
+
+def read_index(f):
+    assert f.read(4) == "DIRC"
+    (version, num_entries) = struct.unpack(">LL", f.read(4 * 2))
+    assert version in (1, 2)
+    for i in range(num_entries):
+        yield read_cache_entry(f)
+
+
+def write_index(f, entries):
+    f.write("DIRC")
+    f.write(struct.pack(">LL", 2, len(entries)))
+    for x in entries:
+        write_cache_entry(f, x)
+
+
 class Index(object):
 
     def __init__(self, filename):
+        self._entries = []
         f = open(filename, 'r')
+        self._byname = {}
         try:
-            assert f.read(4) == "DIRC"
-            (version, self._num_entries) = struct.unpack(">LL", f.read(4 * 2))
-            assert version in (1, 2)
-            self._entries = []
-            for i in range(len(self)):
-                self._entries.append(read_cache_entry(f))
+            for x in read_index(f):
+                self._entries.append(x)
+                self._byname[x[0]] = x
         finally:
             f.close()
 
     def __len__(self):
-        return self._num_entries
+        return len(self._entries)
 
     def items(self):
         return list(self._entries)
 
     def __iter__(self):
         return iter(self._entries)
+
+    def __getitem__(self, name):
+        return self._byname[name]