'''Extends Mercurial feature related to Changeset Evolution

This extension Provide several command tommutate history and deal with issue it may raise.

It also:

    - enable the "Changeset Obsolescence" feature of mercurial,

    - alter core command and extension that rewrite history to use this feature,

    - improve some aspect of the early implementation in 2.3

'''

from mercurial import util

try:

    from mercurial import obsolete

    if not obsolete._enabled:

        obsolete._enabled = True

except ImportError:

    raise util.Abort('Obsolete extension requires Mercurial 2.3 (or later)')

from mercurial import discovery

from mercurial import hg

from mercurial import localrepo

from mercurial import revset

from mercurial import templatekw

from mercurial.node import nullid

# This extension contains the following code

#

# - Extension Helper code

# - Obsolescence cache

# - ...

# - Older format compat

#####################################################################

### Extension helper                                              ###

#####################################################################

class exthelper(object):

    """Helper for modular extension setup

    A single helper should be instanciated for each extension. Helper

    methods are then used as decorator for various purpose.

    All decorators return the original function and may be chained.

    """

    def __init__(self):

        self._uicallables = []

        self._extcallables = []

        self._repocallables = []

        self._revsetsymbols = []

        self._templatekws = []

        self._commandwrappers = []

        self._extcommandwrappers = []

        self._functionwrappers = []

        self._duckpunchers = []

    def final_uisetup(self, ui):

        """Method to be used as the extension uisetup

        The following operations belong here:

        - Changes to ui.__class__ . The ui object that will be used to run the

          command has not yet been created. Changes made here will affect ui

          objects created after this, and in particular the ui that will be

          passed to runcommand

        - Command wraps (extensions.wrapcommand)

        - Changes that need to be visible to other extensions: because

          initialization occurs in phases (all extensions run uisetup, then all

          run extsetup), a change made here will be visible to other extensions

          during extsetup

        - Monkeypatch or wrap function (extensions.wrapfunction) of dispatch

          module members

        - Setup of pre-* and post-* hooks

        - pushkey setup

        """

        for cont, funcname, func in self._duckpunchers:

            setattr(cont, funcname, func)

        for command, wrapper in self._commandwrappers:

            extensions.wrapcommand(commands.table, command, wrapper)

        for cont, funcname, wrapper in self._functionwrappers:

            extensions.wrapfunction(cont, funcname, wrapper)

        for c in self._uicallables:

            c(ui)

    def final_extsetup(self, ui):

        """Method to be used as a the extension extsetup

        The following operations belong here:

        - Changes depending on the status of other extensions. (if

          extensions.find('mq'))

        - Add a global option to all commands

        - Register revset functions

        """

        knownexts = {}

        for name, symbol in self._revsetsymbols:

            revset.symbols[name] = symbol

        for name, kw in self._templatekws:

            templatekw.keywords[name] = kw

        for ext, command, wrapper in self._extcommandwrappers:

            if ext not in knownexts:

                e = extensions.find(ext)

                if e is None:

                    raise util.Abort('extension %s not found' % ext)

                knownexts[ext] = e.cmdtable

            extensions.wrapcommand(knownexts[ext], commands, wrapper)

        for c in self._extcallables:

            c(ui)

    def final_reposetup(self, ui, repo):

        """Method to be used as a the extension reposetup

        The following operations belong here:

        - All hooks but pre-* and post-*

        - Modify configuration variables

        - Changes to repo.__class__, repo.dirstate.__class__

        """

        for c in self._repocallables:

            c(ui, repo)

    def uisetup(self, call):

        """Decorated function will be executed during uisetup

        example::

            @eh.uisetup

            def setupbabar(ui):

                print 'this is uisetup!'

        """

        self._uicallables.append(call)

        return call

    def extsetup(self, call):

        """Decorated function will be executed during extsetup

        example::

            @eh.extsetup

            def setupcelestine(ui):

                print 'this is extsetup!'

        """

        self._uicallables.append(call)

        return call

    def reposetup(self, call):

        """Decorated function will be executed during reposetup

        example::

            @eh.reposetup

            def setupzephir(ui, repo):

                print 'this is reposetup!'

        """

        self._repocallables.append(call)

        return call

    def revset(self, symbolname):

        """Decorated function is a revset symbol

        The name of the symbol must be given as the decorator argument.

        The symbol is added during `extsetup`.

        example::

            @eh.revset('hidden')

            def revsetbabar(repo, subset, x):

                args = revset.getargs(x, 0, 0, 'babar accept no argument')

                return [r for r in subset if 'babar' in repo[r].description()]

        """

        def dec(symbol):

            self._revsetsymbols.append((symbolname, symbol))

            return symbol

        return dec

    def templatekw(self, keywordname):

        """Decorated function is a revset keyword

        The name of the keyword must be given as the decorator argument.

        The symbol is added during `extsetup`.

        example::

            @eh.templatekw('babar')

            def kwbabar(ctx):

                return 'babar'

        """

        def dec(keyword):

            self._templatekws.append((keywordname, keyword))

            return keyword

        return dec

    def wrapcommand(self, command, extension=None):

        """Decorated function is a command wrapper

        The name of the command must be given as the decorator argument.

        The wrapping is installed during `uisetup`.

        If the second option `extension` argument is provided, the wrapping

        will be applied in the extension commandtable. This argument must be a

        string that will be searched using `extension.find` if not found and

        Abort error is raised. If the wrapping applies to an extension, it is

        installed during `extsetup`

        example::

            @eh.wrapcommand('summary')

            def wrapsummary(orig, ui, repo, *args, **kwargs):

                ui.note('Barry!')

                return orig(ui, repo, *args, **kwargs)

        """

        def dec(wrapper):

            if extension is None:

                self._commandwrappers.append((command, wrapper))

            else:

                self._extcommandwrappers.append((extension, command, wrapper))

            return wrapper

        return dec

    def wrapfunction(self, container, funcname):

        """Decorated function is a function wrapper

        This function takes two arguments, the container and the name of the

        function to wrap. The wrapping is performed during `uisetup`.

        (there is no extension support)

        example::

            @eh.function(discovery, 'checkheads')

            def wrapfunction(orig, *args, **kwargs):

                ui.note('His head smashed in and his heart cut out')

                return orig(*args, **kwargs)

        """

        def dec(wrapper):

            self._functionwrappers.append((container, funcname, wrapper))

            return wrapper

        return dec

    def addattr(self, container, funcname):

        """Decorated function is to be added to the container

        This function takes two arguments, the container and the name of the

        function to wrap. The wrapping is performed during `uisetup`.

        example::

            @eh.function(context.changectx, 'babar')

            def babar(ctx):

                return 'babar' in ctx.description

        """

        def dec(func):

            self._duckpunchers.append((container, funcname, func))

            return func

        return dec

eh = exthelper()

uisetup = eh.final_uisetup

extsetup = eh.final_extsetup

reposetup = eh.final_reposetup

#####################################################################

### Obsolescence Caching Logic                                    ###

#####################################################################

# Obsolescence related logic can be very slow if we don't have efficient cache.

#

# This section implements a cache mechanism that did not make it into core for

# time reason. It store meaningful set of revision related to obsolescence

# (obsolete, unstabletble ...

#

# Here is:

#

# - Computation of meaningful set,

# - Cache access logic,

# - Cache invalidation logic,

# - revset and ctx using this cache.

#

### Computation of meaningful set

#

# Most set can be computed with "simple" revset.

#: { set name -> function to compute this set } mapping

#:   function take a single "repo" argument.

#:

#: Use the `cachefor` decorator to register new cache function

cachefuncs = {}

def cachefor(name):

    """Decorator to register a function as computing the cache for a set"""

    def decorator(func):

        assert name not in cachefuncs

        cachefuncs[name] = func

        return func

    return decorator

@cachefor('obsolete')

def _computeobsoleteset(repo):

    """the set of obsolete revisions"""

    obs = set()

    nm = repo.changelog.nodemap

    for prec in repo.obsstore.precursors:

        rev = nm.get(prec)

        if rev is not None:

            obs.add(rev)

    return set(repo.revs('%ld - public()', obs))

@cachefor('unstable')

def _computeunstableset(repo):

    """the set of non obsolete revisions with obsolete parents"""

    return set(repo.revs('(obsolete()::) - obsolete()'))

@cachefor('suspended')

def _computesuspendedset(repo):

    """the set of obsolete parents with non obsolete descendants"""

    return set(repo.revs('obsolete() and obsolete()::unstable()'))

@cachefor('extinct')

def _computeextinctset(repo):

    """the set of obsolete parents without non obsolete descendants"""

    return set(repo.revs('obsolete() - obsolete()::unstable()'))

@eh.wrapfunction(obsolete.obsstore, '__init__')

def _initobsstorecache(orig, obsstore, *args, **kwargs):

    """add a cache attribute to obsstore"""

    obsstore.caches = {}

    return orig(obsstore, *args, **kwargs)

### Cache access

def getobscache(repo, name):

    """Return the set of revision that belong to the <name> set

    Such access may compute the set and cache it for future use"""

    if not repo.obsstore:

        return ()

    if name not in repo.obsstore.caches:

        repo.obsstore.caches[name] = cachefuncs[name](repo)

    return repo.obsstore.caches[name]

### Cache clean up

#

# To be simple we need to invalidate obsolescence cache when:

#

# - new changeset is added:

# - public phase is changed

# - obsolescence marker are added

# - strip is used a repo

def clearobscaches(repo):

    """Remove all obsolescence related cache from a repo

    This remove all cache in obsstore is the obsstore already exist on the

    repo.

    (We could be smarter here)"""

    if 'obsstore' in repo._filecache:

        repo.obsstore.caches.clear()

@eh.wrapfunction(localrepo.localrepository, 'addchangegroup')  # new changeset

@eh.wrapfunction(phases, 'retractboundary')  # phase movement

@eh.wrapfunction(phases, 'advanceboundary')  # phase movement

@eh.wrapfunction(localrepo.localrepository, 'destroyed')  # strip

def wrapclearcache(orig, repo, *args, **kwargs):

    try:

        return orig(repo, *args, **kwargs)

    finally:

        # we are a bit wide here

        # we could restrict to:

        # advanceboundary + phase==public

        # retractboundary + phase==draft

        clearobscaches(repo)

@eh.wrapfunction(obsolete.obsstore, 'add')  # new marker

def clearonadd(orig, obsstore, *args, **kwargs):

    try:

        return orig(obsstore, *args, **kwargs)

    finally:

        obsstore.caches.clear()

### Use the case

# Function in core that could benefic from the cache are overwritten by cache using version

# changectx method

@eh.addattr(context.changectx, 'unstable')

def unstable(ctx):