X-Git-Url: https://git.distorted.org.uk/~mdw/stgit/blobdiff_plain/d1eb3f85c890ab979bb95febf1060f351b39daf3..681f805ef4688c7ea450f5e72a15dad818809734:/stgit/git.py

diff --git a/stgit/git.py b/stgit/git.py
index cc0ae79..038aaac 100644
--- a/stgit/git.py
+++ b/stgit/git.py
@@ -18,26 +18,53 @@ along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 """
 
-import sys, os, glob, popen2
+import sys, os, popen2, re, gitmergeonefile
 
+from stgit import basedir
 from stgit.utils import *
+from stgit.config import config
 
 # git exception class
 class GitException(Exception):
     pass
 
 
-# Different start-up variables read from the environment
-if 'GIT_DIR' in os.environ:
-    base_dir = os.environ['GIT_DIR']
-else:
-    base_dir = '.git'
-
-head_link = os.path.join(base_dir, 'HEAD')
 
 #
 # Classes
 #
+
+class Person:
+    """An author, committer, etc."""
+    def __init__(self, name = None, email = None, date = '',
+                 desc = None):
+        if name or email or date:
+            assert not desc
+            self.name = name
+            self.email = email
+            self.date = date
+        elif desc:
+            assert not (name or email or date)
+            def parse_desc(s):
+                m = re.match(r'^(.+)<(.+)>(.*)$', s)
+                assert m
+                return [x.strip() or None for x in m.groups()]
+            self.name, self.email, self.date = parse_desc(desc)
+    def set_name(self, val):
+        if val:
+            self.name = val
+    def set_email(self, val):
+        if val:
+            self.email = val
+    def set_date(self, val):
+        if val:
+            self.date = val
+    def __str__(self):
+        if self.name and self.email:
+            return '%s <%s>' % (self.name, self.email)
+        else:
+            raise GitException, 'not enough identity data'
+
 class Commit:
     """Handle the commit objects
     """
@@ -45,7 +72,6 @@ class Commit:
         self.__id_hash = id_hash
 
         lines = _output_lines('git-cat-file commit %s' % id_hash)
-        self.__parents = []
         for i in range(len(lines)):
             line = lines[i]
             if line == '\n':
@@ -53,13 +79,11 @@ class Commit:
             field = line.strip().split(' ', 1)
             if field[0] == 'tree':
                 self.__tree = field[1]
-            elif field[0] == 'parent':
-                self.__parents.append(field[1])
             if field[0] == 'author':
                 self.__author = field[1]
             if field[0] == 'committer':
                 self.__committer = field[1]
-        self.__log = ''.join(lines[i:])
+        self.__log = ''.join(lines[i+1:])
 
     def get_id_hash(self):
         return self.__id_hash
@@ -68,10 +92,15 @@ class Commit:
         return self.__tree
 
     def get_parent(self):
-        return self.__parents[0]
+        parents = self.get_parents()
+        if parents:
+            return parents[0]
+        else:
+            return None
 
     def get_parents(self):
-        return self.__parents
+        return _output_lines('git-rev-list --parents --max-count=1 %s'
+                             % self.__id_hash)[0].split()[1:]
 
     def get_author(self):
         return self.__author
@@ -82,16 +111,22 @@ class Commit:
     def get_log(self):
         return self.__log
 
+    def __str__(self):
+        return self.get_id_hash()
+
 # dictionary of Commit objects, used to avoid multiple calls to git
 __commits = dict()
 
 #
 # Functions
 #
+
 def get_commit(id_hash):
     """Commit objects factory. Save/look-up them in the __commits
     dictionary
     """
+    global __commits
+
     if id_hash in __commits:
         return __commits[id_hash]
     else:
@@ -102,7 +137,7 @@ def get_commit(id_hash):
 def get_conflicts():
     """Return the list of file conflicts
     """
-    conflicts_file = os.path.join(base_dir, 'conflicts')
+    conflicts_file = os.path.join(basedir.get(), 'conflicts')
     if os.path.isfile(conflicts_file):
         f = file(conflicts_file)
         names = [line.strip() for line in f.readlines()]
@@ -112,7 +147,7 @@ def get_conflicts():
         return None
 
 def _input(cmd, file_desc):
-    p = popen2.Popen3(cmd)
+    p = popen2.Popen3(cmd, True)
     while True:
         line = file_desc.readline()
         if not line:
@@ -120,31 +155,43 @@ def _input(cmd, file_desc):
         p.tochild.write(line)
     p.tochild.close()
     if p.wait():
-        raise GitException, '%s failed' % str(cmd)
+        raise GitException, '%s failed (%s)' % (str(cmd),
+                                                p.childerr.read().strip())
+
+def _input_str(cmd, string):
+    p = popen2.Popen3(cmd, True)
+    p.tochild.write(string)
+    p.tochild.close()
+    if p.wait():
+        raise GitException, '%s failed (%s)' % (str(cmd),
+                                                p.childerr.read().strip())
 
 def _output(cmd):
-    p=popen2.Popen3(cmd)
-    string = p.fromchild.read()
+    p=popen2.Popen3(cmd, True)
+    output = p.fromchild.read()
     if p.wait():
-        raise GitException, '%s failed' % str(cmd)
-    return string
+        raise GitException, '%s failed (%s)' % (str(cmd),
+                                                p.childerr.read().strip())
+    return output
 
 def _output_one_line(cmd, file_desc = None):
-    p=popen2.Popen3(cmd)
+    p=popen2.Popen3(cmd, True)
     if file_desc != None:
         for line in file_desc:
             p.tochild.write(line)
         p.tochild.close()
-    string = p.fromchild.readline().strip()
+    output = p.fromchild.readline().strip()
     if p.wait():
-        raise GitException, '%s failed' % str(cmd)
-    return string
+        raise GitException, '%s failed (%s)' % (str(cmd),
+                                                p.childerr.read().strip())
+    return output
 
 def _output_lines(cmd):
-    p=popen2.Popen3(cmd)
+    p=popen2.Popen3(cmd, True)
     lines = p.fromchild.readlines()
     if p.wait():
-        raise GitException, '%s failed' % str(cmd)
+        raise GitException, '%s failed (%s)' % (str(cmd),
+                                                p.childerr.read().strip())
     return lines
 
 def __run(cmd, args=None):
@@ -166,20 +213,23 @@ def __run(cmd, args=None):
         return r
     return 0
 
-def __check_base_dir():
-    return os.path.isdir(base_dir)
-
-def __tree_status(files = [], tree_id = 'HEAD', unknown = False,
-                  noexclude = True):
+def __tree_status(files = None, tree_id = 'HEAD', unknown = False,
+                  noexclude = True, verbose = False):
     """Returns a list of pairs - [status, filename]
     """
-    os.system('git-update-index --refresh > /dev/null')
+    if verbose and sys.stdout.isatty():
+        print 'Checking for changes in the working directory...',
+        sys.stdout.flush()
+
+    refresh_index()
 
+    if not files:
+        files = []
     cache_files = []
 
     # unknown files
     if unknown:
-        exclude_file = os.path.join(base_dir, 'info', 'exclude')
+        exclude_file = os.path.join(basedir.get(), 'info', 'exclude')
         base_exclude = ['--exclude=%s' % s for s in
                         ['*.[ao]', '*.pyc', '.*', '*~', '#*', 'TAGS', 'tags']]
         base_exclude.append('--exclude-per-directory=.gitignore')
@@ -191,8 +241,8 @@ def __tree_status(files = [], tree_id = 'HEAD', unknown = False,
         if noexclude:
             extra_exclude = base_exclude = []
 
-        lines = _output_lines(['git-ls-files', '--others'] + base_exclude
-                        + extra_exclude)
+        lines = _output_lines(['git-ls-files', '--others', '--directory']
+                        + base_exclude + extra_exclude)
         cache_files += [('?', line.strip()) for line in lines]
 
     # conflicted files
@@ -202,41 +252,155 @@ def __tree_status(files = [], tree_id = 'HEAD', unknown = False,
     cache_files += [('C', filename) for filename in conflicts]
 
     # the rest
-    for line in _output_lines(['git-diff-index', '-r', tree_id] + files):
+    for line in _output_lines(['git-diff-index', tree_id, '--'] + files):
         fs = tuple(line.rstrip().split(' ',4)[-1].split('\t',1))
         if fs[1] not in conflicts:
             cache_files.append(fs)
 
+    if verbose and sys.stdout.isatty():
+        print 'done'
+
     return cache_files
 
-def local_changes():
+def local_changes(verbose = True):
     """Return true if there are local changes in the tree
     """
-    return len(__tree_status()) != 0
+    return len(__tree_status(verbose = verbose)) != 0
+
+# HEAD value cached
+__head = None
 
 def get_head():
-    """Returns a string representing the HEAD
+    """Verifies the HEAD and returns the SHA1 id that represents it
     """
-    return read_string(head_link)
+    global __head
+
+    if not __head:
+        __head = rev_parse('HEAD')
+    return __head
 
 def get_head_file():
     """Returns the name of the file pointed to by the HEAD link
     """
-    # valid link
-    if os.path.islink(head_link) and os.path.isfile(head_link):
-        return os.path.basename(os.readlink(head_link))
-    else:
-        raise GitException, 'Invalid .git/HEAD link. Git tree not initialised?'
+    return strip_prefix('refs/heads/',
+                        _output_one_line('git-symbolic-ref HEAD'))
+
+def set_head_file(ref):
+    """Resets HEAD to point to a new ref
+    """
+    # head cache flushing is needed since we might have a different value
+    # in the new head
+    __clear_head_cache()
+    if __run('git-symbolic-ref HEAD',
+             [os.path.join('refs', 'heads', ref)]) != 0:
+        raise GitException, 'Could not set head to "%s"' % ref
 
 def __set_head(val):
     """Sets the HEAD value
     """
-    write_string(head_link, val)
+    global __head
+
+    if not __head or __head != val:
+        if __run('git-update-ref HEAD', [val]) != 0:
+            raise GitException, 'Could not update HEAD to "%s".' % val
+        __head = val
+
+    # only allow SHA1 hashes
+    assert(len(__head) == 40)
+
+def __clear_head_cache():
+    """Sets the __head to None so that a re-read is forced
+    """
+    global __head
+
+    __head = None
+
+def refresh_index():
+    """Refresh index with stat() information from the working directory.
+    """
+    __run('git-update-index -q --unmerged --refresh')
 
 def rev_parse(git_id):
-    """Parse the string and return an SHA1 id
+    """Parse the string and return a verified SHA1 id
+    """
+    try:
+        return _output_one_line(['git-rev-parse', '--verify', git_id])
+    except GitException:
+        raise GitException, 'Unknown revision: %s' % git_id
+
+def branch_exists(branch):
+    """Existence check for the named branch
+    """
+    branch = os.path.join('refs', 'heads', branch)
+    for line in _output_lines('git-rev-parse --symbolic --all 2>&1'):
+        if line.strip() == branch:
+            return True
+        if re.compile('[ |/]'+branch+' ').search(line):
+            raise GitException, 'Bogus branch: %s' % line
+    return False
+
+def create_branch(new_branch, tree_id = None):
+    """Create a new branch in the git repository
     """
-    _output(['git-rev-parse', git_id])
+    if branch_exists(new_branch):
+        raise GitException, 'Branch "%s" already exists' % new_branch
+
+    current_head = get_head()
+    set_head_file(new_branch)
+    __set_head(current_head)
+
+    # a checkout isn't needed if new branch points to the current head
+    if tree_id:
+        switch(tree_id)
+
+    if os.path.isfile(os.path.join(basedir.get(), 'MERGE_HEAD')):
+        os.remove(os.path.join(basedir.get(), 'MERGE_HEAD'))
+
+def switch_branch(new_branch):
+    """Switch to a git branch
+    """
+    global __head
+
+    if not branch_exists(new_branch):
+        raise GitException, 'Branch "%s" does not exist' % new_branch
+
+    tree_id = rev_parse(os.path.join('refs', 'heads', new_branch)
+                        + '^{commit}')
+    if tree_id != get_head():
+        refresh_index()
+        if __run('git-read-tree -u -m', [get_head(), tree_id]) != 0:
+            raise GitException, 'git-read-tree failed (local changes maybe?)'
+        __head = tree_id
+    set_head_file(new_branch)
+
+    if os.path.isfile(os.path.join(basedir.get(), 'MERGE_HEAD')):
+        os.remove(os.path.join(basedir.get(), 'MERGE_HEAD'))
+
+def delete_branch(name):
+    """Delete a git branch
+    """
+    if not branch_exists(name):
+        raise GitException, 'Branch "%s" does not exist' % name
+    remove_file_and_dirs(os.path.join(basedir.get(), 'refs', 'heads'),
+                         name)
+
+def rename_branch(from_name, to_name):
+    """Rename a git branch
+    """
+    if not branch_exists(from_name):
+        raise GitException, 'Branch "%s" does not exist' % from_name
+    if branch_exists(to_name):
+        raise GitException, 'Branch "%s" already exists' % to_name
+
+    if get_head_file() == from_name:
+        set_head_file(to_name)
+    rename(os.path.join(basedir.get(), 'refs', 'heads'),
+           from_name, to_name)
+
+    reflog_dir = os.path.join(basedir.get(), 'logs', 'refs', 'heads')
+    if os.path.exists(reflog_dir) \
+           and os.path.exists(os.path.join(reflog_dir, from_name)):
+        rename(reflog_dir, from_name, to_name)
 
 def add(names):
     """Add the files or recursively add the directory contents
@@ -265,11 +429,6 @@ def add(names):
 def rm(files, force = False):
     """Remove a file from the repository
     """
-    if force:
-        git_opt = '--force-remove'
-    else:
-        git_opt = '--remove'
-
     if not force:
         for f in files:
             if os.path.exists(f):
@@ -280,10 +439,67 @@ def rm(files, force = False):
         if files:
             __run('git-update-index --force-remove --', files)
 
-def update_cache(files = [], force = False):
+# Persons caching
+__user = None
+__author = None
+__committer = None
+
+def user():
+    """Return the user information.
+    """
+    global __user
+    if not __user:
+        name=config.get('user.name')
+        email=config.get('user.email')
+        if name and email:
+            __user = Person(name, email)
+        else:
+            raise GitException, 'unknown user details'
+    return __user;
+
+def author():
+    """Return the author information.
+    """
+    global __author
+    if not __author:
+        try:
+            # the environment variables take priority over config
+            try:
+                date = os.environ['GIT_AUTHOR_DATE']
+            except KeyError:
+                date = ''
+            __author = Person(os.environ['GIT_AUTHOR_NAME'],
+                              os.environ['GIT_AUTHOR_EMAIL'],
+                              date)
+        except KeyError:
+            __author = user()
+    return __author
+
+def committer():
+    """Return the author information.
+    """
+    global __committer
+    if not __committer:
+        try:
+            # the environment variables take priority over config
+            try:
+                date = os.environ['GIT_COMMITTER_DATE']
+            except KeyError:
+                date = ''
+            __committer = Person(os.environ['GIT_COMMITTER_NAME'],
+                                 os.environ['GIT_COMMITTER_EMAIL'],
+                                 date)
+        except KeyError:
+            __committer = user()
+    return __committer
+
+def update_cache(files = None, force = False):
     """Update the cache information for the given files
     """
-    cache_files = __tree_status(files)
+    if not files:
+        files = []
+
+    cache_files = __tree_status(files, verbose = False)
 
     # everything is up-to-date
     if len(cache_files) == 0:
@@ -308,12 +524,17 @@ def update_cache(files = [], force = False):
 
     return True
 
-def commit(message, files = [], parents = [], allowempty = False,
+def commit(message, files = None, parents = None, allowempty = False,
            cache_update = True, tree_id = None,
            author_name = None, author_email = None, author_date = None,
            committer_name = None, committer_email = None):
     """Commit the current tree to repository
     """
+    if not files:
+        files = []
+    if not parents:
+        parents = []
+
     # Get the tree status
     if cache_update and parents != []:
         changes = update_cache(files)
@@ -321,7 +542,9 @@ def commit(message, files = [], parents = [], allowempty = False,
             raise GitException, 'No changes to commit'
 
     # get the commit message
-    if message[-1:] != '\n':
+    if not message:
+        message = '\n'
+    elif message[-1:] != '\n':
         message += '\n'
 
     must_switch = True
@@ -355,21 +578,97 @@ def commit(message, files = [], parents = [], allowempty = False,
 
     return commit_id
 
-def merge(base, head1, head2):
-    """Perform a 3-way merge between base, head1 and head2 into the
-    local tree
+def apply_diff(rev1, rev2, check_index = True, files = None):
+    """Apply the diff between rev1 and rev2 onto the current
+    index. This function doesn't need to raise an exception since it
+    is only used for fast-pushing a patch. If this operation fails,
+    the pushing would fall back to the three-way merge.
     """
-    if __run('git-read-tree -u -m', [base, head1, head2]) != 0:
-        raise GitException, 'git-read-tree failed (local changes maybe?)'
+    if check_index:
+        index_opt = '--index'
+    else:
+        index_opt = ''
 
-    # this can fail if there are conflicts
-    if os.system('git-merge-index -o -q gitmergeonefile.py -a') != 0:
-        raise GitException, 'git-merge-cache failed (possible conflicts)'
+    if not files:
+        files = []
 
-def status(files = [], modified = False, new = False, deleted = False,
+    diff_str = diff(files, rev1, rev2)
+    if diff_str:
+        try:
+            _input_str('git-apply %s' % index_opt, diff_str)
+        except GitException:
+            return False
+
+    return True
+
+def merge(base, head1, head2, recursive = False):
+    """Perform a 3-way merge between base, head1 and head2 into the
+    local tree
+    """
+    refresh_index()
+
+    if recursive:
+        # this operation tracks renames but it is slower (used in
+        # general when pushing or picking patches)
+        try:
+            # use _output() to mask the verbose prints of the tool
+            _output('git-merge-recursive %s -- %s %s' % (base, head1, head2))
+        except GitException:
+            pass
+    else:
+        # the fast case where we don't track renames (used when the
+        # distance between base and heads is small, i.e. folding or
+        # synchronising patches)
+        if __run('git-read-tree -u -m --aggressive',
+                 [base, head1, head2]) != 0:
+            raise GitException, 'git-read-tree failed (local changes maybe?)'
+
+    # check the index for unmerged entries
+    files = {}
+    stages_re = re.compile('^([0-7]+) ([0-9a-f]{40}) ([1-3])\t(.*)$', re.S)
+
+    for line in _output('git-ls-files --unmerged --stage -z').split('\0'):
+        if not line:
+            continue
+
+        mode, hash, stage, path = stages_re.findall(line)[0]
+
+        if not path in files:
+            files[path] = {}
+            files[path]['1'] = ('', '')
+            files[path]['2'] = ('', '')
+            files[path]['3'] = ('', '')
+
+        files[path][stage] = (mode, hash)
+
+    # merge the unmerged files
+    errors = False
+    for path in files:
+        # remove additional files that might be generated for some
+        # newer versions of GIT
+        for suffix in [base, head1, head2]:
+            if not suffix:
+                continue
+            fname = path + '~' + suffix
+            if os.path.exists(fname):
+                os.remove(fname)
+
+        stages = files[path]
+        if gitmergeonefile.merge(stages['1'][1], stages['2'][1],
+                                 stages['3'][1], path, stages['1'][0],
+                                 stages['2'][0], stages['3'][0]) != 0:
+            errors = True
+
+    if errors:
+        raise GitException, 'GIT index merging failed (possible conflicts)'
+
+def status(files = None, modified = False, new = False, deleted = False,
            conflict = False, unknown = False, noexclude = False):
     """Show the tree status
     """
+    if not files:
+        files = []
+
     cache_files = __tree_status(files, unknown = True, noexclude = noexclude)
     all = not (modified or new or deleted or conflict or unknown)
 
@@ -389,63 +688,83 @@ def status(files = [], modified = False, new = False, deleted = False,
         cache_files = [x for x in cache_files if x[0] in filestat]
 
     for fs in cache_files:
+        if files and not fs[1] in files:
+            continue
         if all:
             print '%s %s' % (fs[0], fs[1])
         else:
             print '%s' % fs[1]
 
-def diff(files = [], rev1 = 'HEAD', rev2 = None, out_fd = None):
+def diff(files = None, rev1 = 'HEAD', rev2 = None, out_fd = None):
     """Show the diff between rev1 and rev2
     """
-
-    if rev2:
-        diff_str = _output(['git-diff-tree', '-p', rev1, rev2] + files)
+    if not files:
+        files = []
+
+    if rev1 and rev2:
+        diff_str = _output(['git-diff-tree', '-p', rev1, rev2, '--'] + files)
+    elif rev1 or rev2:
+        refresh_index()
+        if rev2:
+            diff_str = _output(['git-diff-index', '-p', '-R', rev2, '--'] + files)
+        else:
+            diff_str = _output(['git-diff-index', '-p', rev1, '--'] + files)
     else:
-        os.system('git-update-index --refresh > /dev/null')
-        diff_str = _output(['git-diff-index', '-p', rev1] + files)
+        diff_str = ''
 
     if out_fd:
         out_fd.write(diff_str)
     else:
         return diff_str
 
-def diffstat(files = [], rev1 = 'HEAD', rev2 = None):
+def diffstat(files = None, rev1 = 'HEAD', rev2 = None):
     """Return the diffstat between rev1 and rev2
     """
+    if not files:
+        files = []
 
     p=popen2.Popen3('git-apply --stat')
     diff(files, rev1, rev2, p.tochild)
     p.tochild.close()
-    str = p.fromchild.read().rstrip()
+    diff_str = p.fromchild.read().rstrip()
     if p.wait():
         raise GitException, 'git.diffstat failed'
-    return str
+    return diff_str
 
 def files(rev1, rev2):
     """Return the files modified between rev1 and rev2
     """
 
-    str = ''
+    result = ''
     for line in _output_lines('git-diff-tree -r %s %s' % (rev1, rev2)):
-        str += '%s %s\n' % tuple(line.rstrip().split(' ',4)[-1].split('\t',1))
+        result += '%s %s\n' % tuple(line.rstrip().split(' ',4)[-1].split('\t',1))
 
-    return str.rstrip()
+    return result.rstrip()
 
 def barefiles(rev1, rev2):
     """Return the files modified between rev1 and rev2, without status info
     """
 
-    str = ''
+    result = ''
     for line in _output_lines('git-diff-tree -r %s %s' % (rev1, rev2)):
-        str += '%s\n' % line.rstrip().split(' ',4)[-1].split('\t',1)[-1]
+        result += '%s\n' % line.rstrip().split(' ',4)[-1].split('\t',1)[-1]
+
+    return result.rstrip()
 
-    return str.rstrip()
+def pretty_commit(commit_id = 'HEAD'):
+    """Return a given commit (log + diff)
+    """
+    return _output(['git-diff-tree', '--cc', '--always', '--pretty', '-r',
+                    commit_id])
 
-def checkout(files = [], tree_id = None, force = False):
+def checkout(files = None, tree_id = None, force = False):
     """Check out the given or all files
     """
-    if tree_id and __run('git-read-tree -m', [tree_id]) != 0:
-        raise GitException, 'Failed git-read-tree -m %s' % tree_id
+    if not files:
+        files = []
+
+    if tree_id and __run('git-read-tree --reset', [tree_id]) != 0:
+        raise GitException, 'Failed git-read-tree --reset %s' % tree_id
 
     checkout_cmd = 'git-checkout-index -q -u'
     if force:
@@ -458,57 +777,175 @@ def checkout(files = [], tree_id = None, force = False):
     if __run(checkout_cmd, files) != 0:
         raise GitException, 'Failed git-checkout-index'
 
-def switch(tree_id):
+def switch(tree_id, keep = False):
     """Switch the tree to the given id
     """
-    if __run('git-read-tree -u -m', [get_head(), tree_id]) != 0:
-        raise GitException, 'git-read-tree failed (local changes maybe?)'
+    if not keep:
+        refresh_index()
+        if __run('git-read-tree -u -m', [get_head(), tree_id]) != 0:
+            raise GitException, 'git-read-tree failed (local changes maybe?)'
 
     __set_head(tree_id)
 
-def reset(tree_id = None):
+def reset(files = None, tree_id = None, check_out = True):
     """Revert the tree changes relative to the given tree_id. It removes
     any local changes
     """
     if not tree_id:
         tree_id = get_head()
 
-    cache_files = __tree_status(tree_id = tree_id)
-    rm_files =  [x[1] for x in cache_files if x[0] in ['D']]
+    if check_out:
+        cache_files = __tree_status(files, tree_id)
+        # files which were added but need to be removed
+        rm_files =  [x[1] for x in cache_files if x[0] in ['A']]
 
-    checkout(tree_id = tree_id, force = True)
-    __set_head(tree_id)
+        checkout(files, tree_id, True)
+        # checkout doesn't remove files
+        map(os.remove, rm_files)
 
-    # checkout doesn't remove files
-    map(os.remove, rm_files)
+    # if the reset refers to the whole tree, switch the HEAD as well
+    if not files:
+        __set_head(tree_id)
 
 def pull(repository = 'origin', refspec = None):
     """Pull changes from the remote repository. At the moment, just
-    use the 'git pull' command
+    use the 'git-pull' command
     """
+    # 'git-pull' updates the HEAD
+    __clear_head_cache()
+
     args = [repository]
     if refspec:
         args.append(refspec)
 
-    if __run('git pull', args) != 0:
-        raise GitException, 'Failed "git pull %s"' % repository
+    if __run(config.get('stgit.pullcmd'), args) != 0:
+        raise GitException, 'Failed "git-pull %s"' % repository
 
-def apply_patch(filename = None):
-    """Apply a patch onto the current index. There must not be any
-    local changes in the tree, otherwise the command fails
+def repack():
+    """Repack all objects into a single pack
     """
-    os.system('git-update-index --refresh > /dev/null')
+    __run('git-repack -a -d -f')
 
-    if filename:
-        if __run('git-apply --index', [filename]) != 0:
-            raise GitException, 'Patch does not apply cleanly'
+def apply_patch(filename = None, diff = None, base = None,
+                fail_dump = True):
+    """Apply a patch onto the current or given index. There must not
+    be any local changes in the tree, otherwise the command fails
+    """
+    if diff is None:
+        if filename:
+            f = file(filename)
+        else:
+            f = sys.stdin
+        diff = f.read()
+        if filename:
+            f.close()
+
+    if base:
+        orig_head = get_head()
+        switch(base)
     else:
-        _input('git-apply --index', sys.stdin)
+        refresh_index()
+
+    try:
+        _input_str('git-apply --index', diff)
+    except GitException:
+        if base:
+            switch(orig_head)
+        if fail_dump:
+            # write the failed diff to a file
+            f = file('.stgit-failed.patch', 'w+')
+            f.write(diff)
+            f.close()
+            print >> sys.stderr, 'Diff written to the .stgit-failed.patch file'
+
+        raise
+
+    if base:
+        top = commit(message = 'temporary commit used for applying a patch',
+                     parents = [base])
+        switch(orig_head)
+        merge(base, orig_head, top)
 
 def clone(repository, local_dir):
     """Clone a remote repository. At the moment, just use the
-    'git clone' script
+    'git-clone' script
     """
-    if __run('git clone', [repository, local_dir]) != 0:
-        raise GitException, 'Failed "git clone %s %s"' \
+    if __run('git-clone', [repository, local_dir]) != 0:
+        raise GitException, 'Failed "git-clone %s %s"' \
               % (repository, local_dir)
+
+def modifying_revs(files, base_rev):
+    """Return the revisions from the list modifying the given files
+    """
+    cmd = ['git-rev-list', '%s..' % base_rev, '--']
+    revs = [line.strip() for line in _output_lines(cmd + files)]
+
+    return revs
+
+
+def refspec_localpart(refspec):
+    m = re.match('^[^:]*:([^:]*)$', refspec)
+    if m:
+        return m.group(1)
+    else:
+        raise GitException, 'Cannot parse refspec "%s"' % line
+
+def refspec_remotepart(refspec):
+    m = re.match('^([^:]*):[^:]*$', refspec)
+    if m:
+        return m.group(1)
+    else:
+        raise GitException, 'Cannot parse refspec "%s"' % line
+    
+
+def __remotes_from_config():
+    return config.sections_matching(r'remote\.(.*)\.url')
+
+def __remotes_from_dir(dir):
+    return os.listdir(os.path.join(basedir.get(), dir))
+
+def remotes_list():
+    """Return the list of remotes in the repository
+    """
+
+    return set(__remotes_from_config()) | \
+           set(__remotes_from_dir('remotes')) | \
+           set(__remotes_from_dir('branches'))
+
+def remotes_local_branches(remote):
+    """Returns the list of local branches fetched from given remote
+    """
+
+    branches = []
+    if remote in __remotes_from_config():
+        for line in config.getall('remote.%s.fetch' % remote):
+            branches.append(refspec_localpart(line))
+    elif remote in __remotes_from_dir('remotes'):
+        stream = open(os.path.join(basedir.get(), 'remotes', remote), 'r')
+        for line in stream:
+            # Only consider Pull lines
+            m = re.match('^Pull: (.*)\n$', line)
+            branches.append(refspec_localpart(m.group(1)))
+        stream.close()
+    elif remote in __remotes_from_dir('branches'):
+        # old-style branches only declare one branch
+        branches.append('refs/heads/'+remote);
+    else:
+        raise GitException, 'Unknown remote "%s"' % remote
+
+    return branches
+
+def identify_remote(branchname):
+    """Return the name for the remote to pull the given branchname
+    from, or None if we believe it is a local branch.
+    """
+
+    for remote in remotes_list():
+        if branchname in remotes_local_branches(remote):
+            return remote
+
+    # FIXME: in the case of local branch we should maybe set remote to
+    # "." but are we even sure it is the only case left ?
+
+    # if we get here we've found nothing
+    return None