+"""A Python class hierarchy wrapping a git repository and its
+contents."""
+
import os, os.path, re
from datetime import datetime, timedelta, tzinfo
from stgit import exception, run, utils
from stgit.config import config
+class Immutable(object):
+ """I{Immutable} objects cannot be modified once created. Any
+ modification methods will return a new object, leaving the
+ original object as it was.
+
+ The reason for this is that we want to be able to represent git
+ objects, which are immutable, and want to be able to create new
+ git objects that are just slight modifications of other git
+ objects. (Such as, for example, modifying the commit message of a
+ commit object while leaving the rest of it intact. This involves
+ creating a whole new commit object that's exactly like the old one
+ except for the commit message.)
+
+ The L{Immutable} class doesn't acytually enforce immutability --
+ that is up to the individual immutable subclasses. It just serves
+ as documentation."""
+
class RepositoryException(exception.StgException):
- pass
+ """Base class for all exceptions due to failed L{Repository}
+ operations."""
class DateException(exception.StgException):
+ """Exception raised when a date+time string could not be parsed."""
def __init__(self, string, type):
exception.StgException.__init__(
self, '"%s" is not a valid %s' % (string, type))
class DetachedHeadException(RepositoryException):
+ """Exception raised when HEAD is detached (that is, there is no
+ current branch)."""
def __init__(self):
RepositoryException.__init__(self, 'Not on any branch')
class Repr(object):
+ """Utility class that defines C{__reps__} in terms of C{__str__}."""
def __repr__(self):
return str(self)
class NoValue(object):
+ """A handy default value that is guaranteed to be distinct from any
+ real argument value."""
pass
def make_defaults(defaults):
return d
class TimeZone(tzinfo, Repr):
+ """A simple time zone class for static offsets from UTC. (We have to
+ define our own since Python's standard library doesn't define any
+ time zone classes.)"""
def __init__(self, tzstring):
m = re.match(r'^([+-])(\d{2}):?(\d{2})$', tzstring)
if not m:
def __str__(self):
return self.__name
-class Date(Repr):
- """Immutable."""
+class Date(Immutable, Repr):
+ """Represents a timestamp used in git commits."""
def __init__(self, datestring):
# Try git-formatted date.
m = re.match(r'^(\d+)\s+([+-]\d\d:?\d\d)$', datestring)
self.__time.tzinfo)
@classmethod
def maybe(cls, datestring):
+ """Return a new object initialized with the argument if it contains a
+ value (otherwise, just return the argument)."""
if datestring in [None, NoValue]:
return datestring
return cls(datestring)
-class Person(Repr):
- """Immutable."""
+class Person(Immutable, Repr):
+ """Represents an author or committer in a git commit object. Contains
+ name, email and timestamp."""
def __init__(self, name = NoValue, email = NoValue,
date = NoValue, defaults = NoValue):
d = make_defaults(defaults)
defaults = cls.user())
return cls.__committer
-class Tree(Repr):
- """Immutable."""
+class Tree(Immutable, Repr):
+ """Represents a git tree object."""
def __init__(self, sha1):
self.__sha1 = sha1
sha1 = property(lambda self: self.__sha1)
def __str__(self):
return 'Tree<%s>' % self.sha1
-class CommitData(Repr):
- """Immutable."""
+class CommitData(Immutable, Repr):
+ """Represents the actual data contents of a git commit object."""
def __init__(self, tree = NoValue, parents = NoValue, author = NoValue,
committer = NoValue, message = NoValue, defaults = NoValue):
d = make_defaults(defaults)
assert False
assert False
-class Commit(Repr):
- """Immutable."""
+class Commit(Immutable, Repr):
+ """Represents a git commit object. All the actual data contents of the
+ commit object is stored in the L{data} member, which is a
+ L{CommitData} object."""
def __init__(self, repository, sha1):
self.__sha1 = sha1
self.__repository = repository
return 'Commit<sha1: %s, data: %s>' % (self.sha1, self.__data)
class Refs(object):
+ """Accessor for the refs stored in a git repository. Will
+ transparently cache the values of all refs."""
def __init__(self, repository):
self.__repository = repository
self.__refs = None
def __cache_refs(self):
+ """(Re-)Build the cache of all refs in the repository."""
self.__refs = {}
for line in self.__repository.run(['git', 'show-ref']).output_lines():
m = re.match(r'^([0-9a-f]{40})\s+(\S+)$', line)
sha1, ref = m.groups()
self.__refs[ref] = sha1
def get(self, ref):
- """Throws KeyError if ref doesn't exist."""
+ """Get the Commit the given ref points to. Throws KeyError if ref
+ doesn't exist."""
if self.__refs == None:
self.__cache_refs()
return self.__repository.get_commit(self.__refs[ref])
def exists(self, ref):
+ """Check if the given ref exists."""
try:
self.get(ref)
except KeyError:
else:
return True
def set(self, ref, commit, msg):
+ """Write the sha1 of the given Commit to the ref. The ref may or may
+ not already exist."""
if self.__refs == None:
self.__cache_refs()
old_sha1 = self.__refs.get(ref, '0'*40)
ref, new_sha1, old_sha1]).no_output()
self.__refs[ref] = new_sha1
def delete(self, ref):
+ """Delete the given ref. Throws KeyError if ref doesn't exist."""
if self.__refs == None:
self.__cache_refs()
self.__repository.run(['git', 'update-ref',
class ObjectCache(object):
"""Cache for Python objects, for making sure that we create only one
- Python object per git object."""
+ Python object per git object. This reduces memory consumption and
+ makes object comparison very cheap."""
def __init__(self, create):
self.__objects = {}
self.__create = create
class RunWithEnv(object):
def run(self, args, env = {}):
+ """Run the given command with an environment given by self.env.
+
+ @type args: list of strings
+ @param args: Command and argument vector
+ @type env: dict
+ @param env: Extra environment"""
return run.Run(*args).env(utils.add_dict(self.env, env))
class RunWithEnvCwd(RunWithEnv):
def run(self, args, env = {}):
+ """Run the given command with an environment given by self.env, and
+ current working directory given by self.cwd.
+
+ @type args: list of strings
+ @param args: Command and argument vector
+ @type env: dict
+ @param env: Extra environment"""
return RunWithEnv.run(self, args, env).cwd(self.cwd)
class Repository(RunWithEnv):
+ """Represents a git repository."""
def __init__(self, directory):
self.__git_dir = directory
self.__refs = Refs(self)
raise RepositoryException('Cannot find git repository')
@property
def default_index(self):
+ """An L{Index} object representing the default index file for the
+ repository."""
if self.__default_index == None:
self.__default_index = Index(
self, (os.environ.get('GIT_INDEX_FILE', None)
or os.path.join(self.__git_dir, 'index')))
return self.__default_index
def temp_index(self):
+ """Return an L{Index} object representing a new temporary index file
+ for the repository."""
return Index(self, self.__git_dir)
@property
def default_worktree(self):
+ """A L{Worktree} object representing the default work tree."""
if self.__default_worktree == None:
path = os.environ.get('GIT_WORK_TREE', None)
if not path:
return self.__default_worktree
@property
def default_iw(self):
+ """An L{IndexAndWorktree} object representing the default index and
+ work tree for this repository."""
if self.__default_iw == None:
self.__default_iw = IndexAndWorktree(self.default_index,
self.default_worktree)
def set_head(self, ref, msg):
self.run(['git', 'symbolic-ref', '-m', msg, 'HEAD', ref]).no_output()
def simple_merge(self, base, ours, theirs):
- """Given three trees, tries to do an in-index merge in a temporary
- index with a temporary index. Returns the result tree, or None if
- the merge failed (due to conflicts)."""
+ """Given three L{Tree}s, tries to do an in-index merge with a
+ temporary index. Returns the result L{Tree}, or None if the
+ merge failed (due to conflicts)."""
assert isinstance(base, Tree)
assert isinstance(ours, Tree)
assert isinstance(theirs, Tree)
finally:
index.delete()
def apply(self, tree, patch_text):
- """Given a tree and a patch, will either return the new tree that
- results when the patch is applied, or None if the patch
+ """Given a L{Tree} and a patch, will either return the new L{Tree}
+ that results when the patch is applied, or None if the patch
couldn't be applied."""
assert isinstance(tree, Tree)
if not patch_text:
finally:
index.delete()
def diff_tree(self, t1, t2, diff_opts):
+ """Given two L{Tree}s C{t1} and C{t2}, return the patch that takes
+ C{t1} to C{t2}.
+
+ @type diff_opts: list of strings
+ @param diff_opts: Extra diff options
+ @rtype: String
+ @return: Patch text"""
assert isinstance(t1, Tree)
assert isinstance(t2, Tree)
return self.run(['git', 'diff-tree', '-p'] + list(diff_opts)
+ [t1.sha1, t2.sha1]).raw_output()
class MergeException(exception.StgException):
- pass
+ """Exception raised when a merge fails for some reason."""
class MergeConflictException(MergeException):
- pass
+ """Exception raised when a merge fails due to conflicts."""
class Index(RunWithEnv):
+ """Represents a git index file."""
def __init__(self, repository, filename):
self.__repository = repository
if os.path.isdir(filename):
return paths
class Worktree(object):
+ """Represents a git worktree (that is, a checked-out file tree)."""
def __init__(self, directory):
self.__directory = directory
env = property(lambda self: { 'GIT_WORK_TREE': '.' })
directory = property(lambda self: self.__directory)
class CheckoutException(exception.StgException):
- pass
+ """Exception raised when a checkout fails."""
class IndexAndWorktree(RunWithEnvCwd):
+ """Represents a git index and a worktree. Anything that an index or
+ worktree can do on their own are handled by the L{Index} and
+ L{Worktree} classes; this class concerns itself with the
+ operations that require both."""
def __init__(self, index, worktree):
self.__index = index
self.__worktree = worktree
+"""The L{StackTransaction} class makes it possible to make complex
+updates to an StGit stack in a safe and convenient way."""
+
from stgit import exception, utils
from stgit.utils import any, all
from stgit.out import *
from stgit.lib import git
class TransactionException(exception.StgException):
- pass
+ """Exception raised when something goes wrong with a
+ L{StackTransaction}."""
class TransactionHalted(TransactionException):
- pass
+ """Exception raised when a L{StackTransaction} stops part-way through.
+ Used to make a non-local jump from the transaction setup to the
+ part of the transaction code where the transaction is run."""
def _print_current_patch(old_applied, new_applied):
def now_at(pn):
now_at(new_applied[-1])
class _TransPatchMap(dict):
+ """Maps patch names to sha1 strings."""
def __init__(self, stack):
dict.__init__(self)
self.__stack = stack
return self.__stack.patches.get(pn).commit
class StackTransaction(object):
+ """A stack transaction, used for making complex updates to an StGit
+ stack in one single operation that will either succeed or fail
+ cleanly.
+
+ The basic theory of operation is the following:
+
+ 1. Create a transaction object.
+
+ 2. Inside a::
+
+ try
+ ...
+ except TransactionHalted:
+ pass
+
+ block, update the transaction with e.g. methods like
+ L{pop_patches} and L{push_patch}. This may create new git
+ objects such as commits, but will not write any refs; this means
+ that in case of a fatal error we can just walk away, no clean-up
+ required.
+
+ (Some operations may need to touch your index and working tree,
+ though. But they are cleaned up when needed.)
+
+ 3. After the C{try} block -- wheher or not the setup ran to
+ completion or halted part-way through by raising a
+ L{TransactionHalted} exception -- call the transaction's L{run}
+ method. This will either succeed in writing the updated state to
+ your refs and index+worktree, or fail without having done
+ anything."""
def __init__(self, stack, msg, allow_conflicts = False):
self.__stack = stack
self.__msg = msg
if iw:
self.__checkout(self.__stack.head.data.tree, iw)
def run(self, iw = None):
+ """Execute the transaction. Will either succeed, or fail (with an
+ exception) and do nothing."""
self.__check_consistency()
new_head = self.__head
def pop_patches(self, p):
"""Pop all patches pn for which p(pn) is true. Return the list of
- other patches that had to be popped to accomplish this."""
+ other patches that had to be popped to accomplish this. Always
+ succeeds."""
popped = []
for i in xrange(len(self.applied)):
if p(self.applied[i]):
def delete_patches(self, p):
"""Delete all patches pn for which p(pn) is true. Return the list of
- other patches that had to be popped to accomplish this."""
+ other patches that had to be popped to accomplish this. Always
+ succeeds."""
popped = []
all_patches = self.applied + self.unapplied
for i in xrange(len(self.applied)):
~mdw / stgit / commitdiff