Change parse_tree to return a list rather than a dict.
[jelmer/dulwich-libgit2.git] / dulwich / objects.py
index bbaba9e94ca37f024965642ebec4625006662cc8..b05f932df3aba50e415f5a7939e5616c4f73cce5 100644 (file)
@@ -36,26 +36,33 @@ from dulwich.errors import (
     NotCommitError,
     NotTreeError,
     )
+from dulwich.file import GitFile
 from dulwich.misc import (
     make_sha,
     )
 
-BLOB_ID = "blob"
-TAG_ID = "tag"
-TREE_ID = "tree"
-COMMIT_ID = "commit"
-PARENT_ID = "parent"
-AUTHOR_ID = "author"
-COMMITTER_ID = "committer"
-OBJECT_ID = "object"
-TYPE_ID = "type"
-TAGGER_ID = "tagger"
-ENCODING_ID = "encoding"
-
-S_IFGITLINK    = 0160000
+
+# Header fields for commits
+_TREE_HEADER = "tree"
+_PARENT_HEADER = "parent"
+_AUTHOR_HEADER = "author"
+_COMMITTER_HEADER = "committer"
+_ENCODING_HEADER = "encoding"
+
+
+# Header fields for objects
+_OBJECT_HEADER = "object"
+_TYPE_HEADER = "type"
+_TAG_HEADER = "tag"
+_TAGGER_HEADER = "tagger"
+
+
+S_IFGITLINK = 0160000
+
 def S_ISGITLINK(m):
     return (stat.S_IFMT(m) == S_IFGITLINK)
 
+
 def _decompress(string):
     dcomp = zlib.decompressobj()
     dcomped = dcomp.decompress(string)
@@ -87,6 +94,15 @@ def serializable_property(name, docstring=None):
     return property(get, set, doc=docstring)
 
 
+def object_class(type):
+    """Get the object class corresponding to the given type.
+
+    :param type: Either a type name string or a numeric type.
+    :return: The ShaFile subclass corresponding to the given type.
+    """
+    return _TYPE_MAP[type]
+
+
 class ShaFile(object):
     """A git SHA file."""
 
@@ -95,10 +111,10 @@ class ShaFile(object):
         """Parse a legacy object, creating it and setting object._text"""
         text = _decompress(map)
         object = None
-        for posstype in type_map.keys():
-            if text.startswith(posstype):
-                object = type_map[posstype]()
-                text = text[len(posstype):]
+        for cls in OBJECT_CLASSES:
+            if text.startswith(cls.type_name):
+                object = cls()
+                text = text[len(cls.type_name):]
                 break
         assert object is not None, "%s is not a known object type" % text[:9]
         assert text[0] == ' ', "%s is not a space" % text[0]
@@ -117,14 +133,24 @@ class ShaFile(object):
         object.set_raw_string(text)
         return object
 
+    def as_legacy_object_chunks(self):
+        compobj = zlib.compressobj()
+        yield compobj.compress(self._header())
+        for chunk in self.as_raw_chunks():
+            yield compobj.compress(chunk)
+        yield compobj.flush()
+
     def as_legacy_object(self):
-        text = self.as_raw_string()
-        return zlib.compress("%s %d\0%s" % (self._type, len(text), text))
+        return "".join(self.as_legacy_object_chunks())
 
-    def as_raw_string(self):
+    def as_raw_chunks(self):
         if self._needs_serialization:
-            self.serialize()
-        return self._text
+            self._chunked_text = self._serialize()
+            self._needs_serialization = False
+        return self._chunked_text
+
+    def as_raw_string(self):
+        return "".join(self.as_raw_chunks())
 
     def __str__(self):
         return self.as_raw_string()
@@ -137,12 +163,16 @@ class ShaFile(object):
 
     def _ensure_parsed(self):
         if self._needs_parsing:
-            self._parse_text()
+            self._deserialize(self._chunked_text)
+            self._needs_parsing = False
 
     def set_raw_string(self, text):
         if type(text) != str:
             raise TypeError(text)
-        self._text = text
+        self.set_raw_chunks([text])
+
+    def set_raw_chunks(self, chunks):
+        self._chunked_text = chunks
         self._sha = None
         self._needs_parsing = True
         self._needs_serialization = False
@@ -153,11 +183,11 @@ class ShaFile(object):
         used = 0
         byte = ord(map[used])
         used += 1
-        num_type = (byte >> 4) & 7
+        type_num = (byte >> 4) & 7
         try:
-            object = num_type_map[num_type]()
+            object = object_class(type_num)()
         except KeyError:
-            raise AssertionError("Not a known type: %d" % num_type)
+            raise AssertionError("Not a known type: %d" % type_num)
         while (byte & 0x80) != 0:
             byte = ord(map[used])
             used += 1
@@ -177,14 +207,17 @@ class ShaFile(object):
         """Don't call this directly"""
         self._sha = None
 
-    def _parse_text(self):
-        """For subclasses to do initialisation time parsing"""
+    def _deserialize(self, chunks):
+        raise NotImplementedError(self._deserialize)
+
+    def _serialize(self):
+        raise NotImplementedError(self._serialize)
 
     @classmethod
     def from_file(cls, filename):
         """Get the contents of a SHA file on disk"""
         size = os.path.getsize(filename)
-        f = open(filename, 'rb')
+        f = GitFile(filename, 'rb')
         try:
             map = mmap.mmap(f.fileno(), size, access=mmap.ACCESS_READ)
             shafile = cls._parse_file(map)
@@ -192,35 +225,56 @@ class ShaFile(object):
         finally:
             f.close()
 
-    @classmethod
-    def from_raw_string(cls, type, string):
+    @staticmethod
+    def from_raw_string(type_num, string):
         """Creates an object of the indicated type from the raw string given.
 
-        Type is the numeric type of an object. String is the raw uncompressed
-        contents.
+        :param type_num: The numeric type of the object.
+        :param string: The raw uncompressed contents.
         """
-        real_class = num_type_map[type]
-        obj = real_class()
-        obj.type = type
+        obj = object_class(type_num)()
         obj.set_raw_string(string)
         return obj
 
+    @staticmethod
+    def from_raw_chunks(type_num, chunks):
+        """Creates an object of the indicated type from the raw chunks given.
+
+        :param type_num: The numeric type of the object.
+        :param chunks: An iterable of the raw uncompressed contents.
+        """
+        obj = object_class(type_num)()
+        obj.set_raw_chunks(chunks)
+        return obj
+
     @classmethod
     def from_string(cls, string):
         """Create a blob from a string."""
-        shafile = cls()
-        shafile.set_raw_string(string)
-        return shafile
+        obj = cls()
+        obj.set_raw_string(string)
+        return obj
 
     def _header(self):
-        return "%s %lu\0" % (self._type, len(self.as_raw_string()))
+        return "%s %lu\0" % (self.type_name, self.raw_length())
+
+    def raw_length(self):
+        """Returns the length of the raw string of this object."""
+        ret = 0
+        for chunk in self.as_raw_chunks():
+            ret += len(chunk)
+        return ret
+
+    def _make_sha(self):
+        ret = make_sha()
+        ret.update(self._header())
+        for chunk in self.as_raw_chunks():
+            ret.update(chunk)
+        return ret
 
     def sha(self):
         """The SHA1 object that is the name of this object."""
         if self._needs_serialization or self._sha is None:
-            self._sha = make_sha()
-            self._sha.update(self._header())
-            self._sha.update(self.as_raw_string())
+            self._sha = self._make_sha()
         return self._sha
 
     @property
@@ -228,11 +282,12 @@ class ShaFile(object):
         return self.sha().hexdigest()
 
     def get_type(self):
-        return self._num_type
+        return self.type_num
 
     def set_type(self, type):
-        self._num_type = type
+        self.type_num = type
 
+    # DEPRECATED: use type_num or type_name as needed.
     type = property(get_type, set_type)
 
     def __repr__(self):
@@ -242,7 +297,7 @@ class ShaFile(object):
         return self.id != other.id
 
     def __eq__(self, other):
-        """Return true id the sha of the two objects match.
+        """Return true if the sha of the two objects match.
 
         The __le__ etc methods aren't overriden as they make no sense,
         certainly at this level.
@@ -253,24 +308,37 @@ class ShaFile(object):
 class Blob(ShaFile):
     """A Git Blob object."""
 
-    _type = BLOB_ID
-    _num_type = 3
-    _needs_serialization = False
-    _needs_parsing = False
+    type_name = 'blob'
+    type_num = 3
+
+    def __init__(self):
+        super(Blob, self).__init__()
+        self._chunked_text = []
+        self._needs_parsing = False
+        self._needs_serialization = False
 
-    def get_data(self):
-        return self._text
+    def _get_data(self):
+        return self.as_raw_string()
 
-    def set_data(self, data):
-        self._text = data
+    def _set_data(self, data):
+        self.set_raw_string(data)
 
-    data = property(get_data, set_data,
+    data = property(_get_data, _set_data,
             "The text contained within the blob object.")
 
+    def _get_chunked(self):
+        return self._chunked_text
+
+    def _set_chunked(self, chunks):
+        self._chunked_text = chunks
+
+    chunked = property(_get_chunked, _set_chunked,
+        "The text within the blob object, as chunks (not necessarily lines).")
+
     @classmethod
     def from_file(cls, filename):
         blob = ShaFile.from_file(filename)
-        if blob._type != cls._type:
+        if not isinstance(blob, cls):
             raise NotBlobError(filename)
         return blob
 
@@ -278,8 +346,8 @@ class Blob(ShaFile):
 class Tag(ShaFile):
     """A Git Tag object."""
 
-    _type = TAG_ID
-    _num_type = 4
+    type_name = 'tag'
+    type_num = 4
 
     def __init__(self):
         super(Tag, self).__init__()
@@ -288,10 +356,10 @@ class Tag(ShaFile):
 
     @classmethod
     def from_file(cls, filename):
-        blob = ShaFile.from_file(filename)
-        if blob._type != cls._type:
-            raise NotBlobError(filename)
-        return blob
+        tag = ShaFile.from_file(filename)
+        if not isinstance(tag, cls):
+            raise NotTagError(filename)
+        return tag
 
     @classmethod
     def from_string(cls, string):
@@ -300,37 +368,38 @@ class Tag(ShaFile):
         shafile.set_raw_string(string)
         return shafile
 
-    def serialize(self):
-        f = StringIO()
-        f.write("%s %s\n" % (OBJECT_ID, self._object_sha))
-        f.write("%s %s\n" % (TYPE_ID, num_type_map[self._object_type]._type))
-        f.write("%s %s\n" % (TAG_ID, self._name))
+    def _serialize(self):
+        chunks = []
+        chunks.append("%s %s\n" % (_OBJECT_HEADER, self._object_sha))
+        chunks.append("%s %s\n" % (_TYPE_HEADER, self._object_class.type_name))
+        chunks.append("%s %s\n" % (_TAG_HEADER, self._name))
         if self._tagger:
             if self._tag_time is None:
-                f.write("%s %s\n" % (TAGGER_ID, self._tagger))
+                chunks.append("%s %s\n" % (_TAGGER_HEADER, self._tagger))
             else:
-                f.write("%s %s %d %s\n" % (TAGGER_ID, self._tagger, self._tag_time, format_timezone(self._tag_timezone)))
-        f.write("\n") # To close headers
-        f.write(self._message)
-        self._text = f.getvalue()
-        self._needs_serialization = False
-
-    def _parse_text(self):
+                chunks.append("%s %s %d %s\n" % (
+                  _TAGGER_HEADER, self._tagger, self._tag_time,
+                  format_timezone(self._tag_timezone)))
+        chunks.append("\n") # To close headers
+        chunks.append(self._message)
+        return chunks
+
+    def _deserialize(self, chunks):
         """Grab the metadata attached to the tag"""
         self._tagger = None
-        f = StringIO(self._text)
+        f = StringIO("".join(chunks))
         for l in f:
             l = l.rstrip("\n")
             if l == "":
                 break # empty line indicates end of headers
             (field, value) = l.split(" ", 1)
-            if field == OBJECT_ID:
+            if field == _OBJECT_HEADER:
                 self._object_sha = value
-            elif field == TYPE_ID:
-                self._object_type = type_map[value]
-            elif field == TAG_ID:
+            elif field == _TYPE_HEADER:
+                self._object_class = object_class(value)
+            elif field == _TAG_HEADER:
                 self._name = value
-            elif field == TAGGER_ID:
+            elif field == _TAGGER_HEADER:
                 try:
                     sep = value.index("> ")
                 except ValueError:
@@ -348,19 +417,21 @@ class Tag(ShaFile):
             else:
                 raise AssertionError("Unknown field %s" % field)
         self._message = f.read()
-        self._needs_parsing = False
 
-    def get_object(self):
-        """Returns the object pointed by this tag, represented as a tuple(type, sha)"""
+    def _get_object(self):
+        """Get the object pointed to by this tag.
+
+        :return: tuple of (object class, sha).
+        """
         self._ensure_parsed()
-        return (self._object_type, self._object_sha)
+        return (self._object_class, self._object_sha)
 
-    def set_object(self, value):
+    def _set_object(self, value):
         self._ensure_parsed()
-        (self._object_type, self._object_sha) = value
+        (self._object_class, self._object_sha) = value
         self._needs_serialization = True
 
-    object = property(get_object, set_object)
+    object = property(_get_object, _set_object)
 
     name = serializable_property("name", "The name of this tag")
     tagger = serializable_property("tagger",
@@ -373,30 +444,55 @@ class Tag(ShaFile):
 
 
 def parse_tree(text):
-    ret = {}
+    """Parse a tree text.
+
+    :param text: Serialized text to parse
+    :yields: tuples of (name, mode, sha)
+    """
     count = 0
     l = len(text)
     while count < l:
         mode_end = text.index(' ', count)
         mode = int(text[count:mode_end], 8)
-
         name_end = text.index('\0', mode_end)
         name = text[mode_end+1:name_end]
-
         count = name_end+21
-
         sha = text[name_end+1:count]
+        yield (name, mode, sha_to_hex(sha))
+
+
+def serialize_tree(items):
+    """Serialize the items in a tree to a text.
+
+    :param items: Sorted iterable over (name, mode, sha) tuples
+    :return: Serialized tree text as chunks
+    """
+    for name, mode, hexsha in items:
+        yield "%04o %s\0%s" % (mode, name, hex_to_sha(hexsha))
+
 
-        ret[name] = (mode, sha_to_hex(sha))
+def sorted_tree_items(entries):
+    """Iterate over a tree entries dictionary in the order in which 
+    the items would be serialized.
 
-    return ret
+    :param entries: Dictionary mapping names to (mode, sha) tuples
+    :return: Iterator over (name, mode, sha)
+    """
+    def cmp_entry((name1, value1), (name2, value2)):
+        if stat.S_ISDIR(value1[0]):
+            name1 += "/"
+        if stat.S_ISDIR(value2[0]):
+            name2 += "/"
+        return cmp(name1, name2)
+    for name, entry in sorted(entries.iteritems(), cmp=cmp_entry):
+        yield name, entry[0], entry[1]
 
 
 class Tree(ShaFile):
     """A Git tree object"""
 
-    _type = TREE_ID
-    _num_type = 2
+    type_name = 'tree'
+    type_num = 2
 
     def __init__(self):
         super(Tree, self).__init__()
@@ -407,7 +503,7 @@ class Tree(ShaFile):
     @classmethod
     def from_file(cls, filename):
         tree = ShaFile.from_file(filename)
-        if tree._type != cls._type:
+        if not isinstance(tree, cls):
             raise NotTreeError(filename)
         return tree
 
@@ -446,41 +542,40 @@ class Tree(ShaFile):
     def entries(self):
         """Return a list of tuples describing the tree entries"""
         self._ensure_parsed()
-        # The order of this is different from iteritems() for historical reasons
-        return [(mode, name, hexsha) for (name, mode, hexsha) in self.iteritems()]
+        # The order of this is different from iteritems() for historical
+        # reasons
+        return [
+            (mode, name, hexsha) for (name, mode, hexsha) in self.iteritems()]
 
     def iteritems(self):
-        def cmp_entry((name1, value1), (name2, value2)):
-            if stat.S_ISDIR(value1[0]):
-                name1 += "/"
-            if stat.S_ISDIR(value2[0]):
-                name2 += "/"
-            return cmp(name1, name2)
+        """Iterate over all entries in the order in which they would be
+        serialized.
+
+        :return: Iterator over (name, mode, sha) tuples
+        """
         self._ensure_parsed()
-        for name, entry in sorted(self._entries.iteritems(), cmp=cmp_entry):
-            yield name, entry[0], entry[1]
+        return sorted_tree_items(self._entries)
 
-    def _parse_text(self):
+    def _deserialize(self, chunks):
         """Grab the entries in the tree"""
-        self._entries = parse_tree(self._text)
+        parsed_entries = parse_tree("".join(chunks))
+        # TODO: list comprehension is for efficiency in the common (small) case;
+        # if memory efficiency in the large case is a concern, use a genexp.
+        self._entries = dict([(n, (m, s)) for n, m, s in parsed_entries])
         self._needs_parsing = False
 
-    def serialize(self):
-        f = StringIO()
-        for name, mode, hexsha in self.iteritems():
-            f.write("%04o %s\0%s" % (mode, name, hex_to_sha(hexsha)))
-        self._text = f.getvalue()
-        self._needs_serialization = False
+    def _serialize(self):
+        return list(serialize_tree(self.iteritems()))
 
     def as_pretty_string(self):
-        text = ""
+        text = []
         for name, mode, hexsha in self.iteritems():
             if mode & stat.S_IFDIR:
                 kind = "tree"
             else:
                 kind = "blob"
-            text += "%04o %s %s\t%s\n" % (mode, kind, hexsha, name)
-        return text
+            text.append("%04o %s %s\t%s\n" % (mode, kind, hexsha, name))
+        return "".join(text)
 
 
 def parse_timezone(text):
@@ -503,8 +598,8 @@ def format_timezone(offset):
 class Commit(ShaFile):
     """A git commit object"""
 
-    _type = COMMIT_ID
-    _num_type = 1
+    type_name = 'commit'
+    type_num = 1
 
     def __init__(self):
         super(Commit, self).__init__()
@@ -512,71 +607,86 @@ class Commit(ShaFile):
         self._encoding = None
         self._needs_parsing = False
         self._needs_serialization = True
+        self._extra = {}
 
     @classmethod
     def from_file(cls, filename):
         commit = ShaFile.from_file(filename)
-        if commit._type != cls._type:
+        if not isinstance(commit, cls):
             raise NotCommitError(filename)
         return commit
 
-    def _parse_text(self):
+    def _deserialize(self, chunks):
         self._parents = []
+        self._extra = []
         self._author = None
-        f = StringIO(self._text)
+        f = StringIO("".join(chunks))
         for l in f:
             l = l.rstrip("\n")
             if l == "":
                 # Empty line indicates end of headers
                 break
             (field, value) = l.split(" ", 1)
-            if field == TREE_ID:
+            if field == _TREE_HEADER:
                 self._tree = value
-            elif field == PARENT_ID:
+            elif field == _PARENT_HEADER:
                 self._parents.append(value)
-            elif field == AUTHOR_ID:
+            elif field == _AUTHOR_HEADER:
                 self._author, timetext, timezonetext = value.rsplit(" ", 2)
                 self._author_time = int(timetext)
                 self._author_timezone = parse_timezone(timezonetext)
-            elif field == COMMITTER_ID:
+            elif field == _COMMITTER_HEADER:
                 self._committer, timetext, timezonetext = value.rsplit(" ", 2)
                 self._commit_time = int(timetext)
                 self._commit_timezone = parse_timezone(timezonetext)
-            elif field == ENCODING_ID:
+            elif field == _ENCODING_HEADER:
                 self._encoding = value
             else:
-                raise AssertionError("Unknown field %s" % field)
+                self._extra.append((field, value))
         self._message = f.read()
-        self._needs_parsing = False
 
-    def serialize(self):
-        f = StringIO()
-        f.write("%s %s\n" % (TREE_ID, self._tree))
+    def _serialize(self):
+        chunks = []
+        chunks.append("%s %s\n" % (_TREE_HEADER, self._tree))
         for p in self._parents:
-            f.write("%s %s\n" % (PARENT_ID, p))
-        f.write("%s %s %s %s\n" % (AUTHOR_ID, self._author, str(self._author_time), format_timezone(self._author_timezone)))
-        f.write("%s %s %s %s\n" % (COMMITTER_ID, self._committer, str(self._commit_time), format_timezone(self._commit_timezone)))
+            chunks.append("%s %s\n" % (_PARENT_HEADER, p))
+        chunks.append("%s %s %s %s\n" % (
+          _AUTHOR_HEADER, self._author, str(self._author_time),
+          format_timezone(self._author_timezone)))
+        chunks.append("%s %s %s %s\n" % (
+          _COMMITTER_HEADER, self._committer, str(self._commit_time),
+          format_timezone(self._commit_timezone)))
         if self.encoding:
-            f.write("%s %s\n" % (ENCODING_ID, self.encoding))
-        f.write("\n") # There must be a new line after the headers
-        f.write(self._message)
-        self._text = f.getvalue()
-        self._needs_serialization = False
+            chunks.append("%s %s\n" % (_ENCODING_HEADER, self.encoding))
+        for k, v in self.extra:
+            if "\n" in k or "\n" in v:
+                raise AssertionError("newline in extra data: %r -> %r" % (k, v))
+            chunks.append("%s %s\n" % (k, v))
+        chunks.append("\n") # There must be a new line after the headers
+        chunks.append(self._message)
+        return chunks
 
     tree = serializable_property("tree", "Tree that is the state of this commit")
 
-    def get_parents(self):
+    def _get_parents(self):
         """Return a list of parents of this commit."""
         self._ensure_parsed()
         return self._parents
 
-    def set_parents(self, value):
-        """Return a list of parents of this commit."""
+    def _set_parents(self, value):
+        """Set a list of parents of this commit."""
         self._ensure_parsed()
         self._needs_serialization = True
         self._parents = value
 
-    parents = property(get_parents, set_parents)
+    parents = property(_get_parents, _set_parents)
+
+    def _get_extra(self):
+        """Return extra settings of this commit."""
+        self._ensure_parsed()
+        return self._extra
+
+    extra = property(_get_extra)
 
     author = serializable_property("author",
         "The name of the author of the commit")
@@ -603,25 +713,26 @@ class Commit(ShaFile):
         "Encoding of the commit message.")
 
 
-type_map = {
-    BLOB_ID : Blob,
-    TREE_ID : Tree,
-    COMMIT_ID : Commit,
-    TAG_ID: Tag,
-}
+OBJECT_CLASSES = (
+    Commit,
+    Tree,
+    Blob,
+    Tag,
+    )
+
+_TYPE_MAP = {}
+
+for cls in OBJECT_CLASSES:
+    _TYPE_MAP[cls.type_name] = cls
+    _TYPE_MAP[cls.type_num] = cls
 
-num_type_map = {
-    0: None,
-    1: Commit,
-    2: Tree,
-    3: Blob,
-    4: Tag,
-    # 5 Is reserved for further expansion
-}
 
+
+# Hold on to the pure-python implementations for testing
+_parse_tree_py = parse_tree
+_sorted_tree_items_py = sorted_tree_items
 try:
     # Try to import C versions
-    from dulwich._objects import parse_tree
+    from dulwich._objects import parse_tree, sorted_tree_items
 except ImportError:
     pass
-