gecko-dev/extensions/python/xpcom/server/loader.py

# The contents of this file are subject to the Mozilla Public License Version
# 1.1 (the "License"); you may not use this file except in compliance with the
# License. You may obtain a copy of the License at http://www.mozilla.org/MPL/
#
# Software distributed under the License is distributed on an "AS IS" basis,
# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
# the specific language governing rights and limitations under the License.
#
# The Original Code is the Python XPCOM language bindings.
#
# The Initial Developer of the Original Code is ActiveState Tool Corp.
# Portions created by ActiveState Tool Corp. are Copyright (C) 2000, 2001
# ActiveState Tool Corp.  All Rights Reserved.
#
# Contributor(s): Mark Hammond <MarkH@ActiveState.com> (original author)
#

import xpcom
from xpcom import components

import factory
import module

import glob, os, types

from xpcom.client import Component

fileSizeValueName = "FileSize"
lastModValueName = "LastModTimeStamp"
xpcomKeyName = "software/mozilla/XPCOM/components"

# Until we get interface constants.
When_Startup = 0
When_Component = 1
When_Timer = 2

def _has_good_attr(object, attr):
    # Actually allows "None" to be specified to disable inherited attributes.
    return getattr(object, attr, None) is not None

def FindCOMComponents(py_module):
    # For now, just run over all classes looking for likely candidates.
    comps = []
    for name, object in py_module.__dict__.items():
        if type(object)==types.ClassType and \
           _has_good_attr(object, "_com_interfaces_") and \
           _has_good_attr(object, "_reg_clsid_") and \
           _has_good_attr(object, "_reg_contractid_"):
            comps.append(object)
    return comps

def register_self(klass, compMgr, location, registryLocation, componentType):
    pcl = PythonComponentLoader
    from xpcom import _xpcom
    svc = _xpcom.GetGlobalServiceManager().getServiceByContractID("@mozilla.org/categorymanager;1", components.interfaces.nsICategoryManager)
    svc.addCategoryEntry("component-loader", pcl._reg_component_type_, pcl._reg_contractid_, 1, 1)

class PythonComponentLoader:
    _com_interfaces_ = components.interfaces.nsIComponentLoader
    _reg_clsid_ = "{63B68B1E-3E62-45f0-98E3-5E0B5797970C}" # Never copy these!
    _reg_contractid_ = "moz.pyloader.1"
    _reg_desc_ = "Python component loader"
    # Optional function which performs additional special registration
    # Appears that no special unregistration is needed for ComponentLoaders, hence no unregister function.
    _reg_registrar_ = (register_self,None)
    # Custom attributes for ComponentLoader registration.
    _reg_component_type_ = "script/python"

    def __init__(self):
        self.com_modules = {} # Keyed by module's FQN as obtained from nsIFile.path

    def _getCOMModuleForLocation(self, componentFile):
        fqn = componentFile.path
        mod = self.com_modules.get(fqn)
        if mod is not None:
            return mod
        import ihooks, sys
        base_name = os.path.splitext(os.path.basename(fqn))[0]
        loader = ihooks.ModuleLoader()

        module_name_in_sys = "component:%s" % (base_name,)
        stuff = loader.find_module(base_name, [componentFile.parent.path])
        assert stuff is not None, "Couldnt find the module '%s'" % (base_name,)
        py_mod = loader.load_module( module_name_in_sys, stuff )

        # Make and remember the COM module.
        comps = FindCOMComponents(py_mod)
        mod = module.Module(comps)
        
        self.com_modules[fqn] = mod
        return mod
        
    def getFactory(self, clsid, location, type):
        # return the factory
        assert type == self._reg_component_type_, "Being asked to create an object not of my type:%s" % (type,)
        file_interface = components.manager.specForRegistryLocation(location)
        # delegate to the module.
        m = self._getCOMModuleForLocation(file_interface)
        return m.getClassObject(components.manager, clsid, components.interfaces.nsIFactory)

    def init(self, comp_mgr, registry):
        # void
        registry = registry.QueryInterface(components.interfaces.nsIRegistry)
        try:
            self.xpcom_registry_key = registry.getSubtree(
                            components.interfaces.nsIRegistry.Common,
                            xpcomKeyName)
            # If we worked, we can use the registry!
            self.registry = registry
        except xpcom.Exception, details:
            print "Registry failed", details
            self.registry = None # no registry ops allowed

        self.comp_mgr = comp_mgr
        if xpcom.verbose:
            print "Python component loader init() called"

     # Called when a component of the appropriate type is registered,
     # to give the component loader an opportunity to do things like
     # annotate the registry and such.
    def onRegister (self, clsid, type, className, proId, location, replace, persist):
        if xpcom.verbose:
            print "Python component loader - onRegister() called"

    def autoRegisterComponents (self, when, directory):
        directory_path = directory.path
        print "Auto-registering all Python components in", directory_path
        import traceback

        # ToDo - work out the right thing here
        # eg - do we recurse?
        # - do we support packages?
        entries = directory.directoryEntries
        while entries.HasMoreElements():
            entry = entries.GetNext(components.interfaces.nsIFile)
            if os.path.splitext(entry.path)[1]==".py":
                try:
                    self.autoRegisterComponent(when, entry)
                except:
                    print "** Registration of '%s' failed!" % (entry.path,)
                    traceback.print_exc()

    def autoRegisterComponent (self, when, componentFile):
        # bool return
        
        reg_loc = components.manager.registryLocationForSpec(componentFile)
        # Use the registry to see if we actually need to do anything
        if not self._hasChanged(reg_loc, componentFile):
            return 1

        # Sheesh - it appears we should also use the observer service
        # to let the system know of our auto-register progress.

        # auto-register via the module.
        m = self._getCOMModuleForLocation(componentFile)
        m.registerSelf(components.manager, componentFile, reg_loc, self._reg_component_type_)
        self._setRegistryInfo(reg_loc, componentFile)
        return 1

    def autoUnregisterComponent (self, when, componentFile):
        # bool return
        # auto-unregister via the module.
        m = self._getCOMModuleForLocation(componentFile)
        reg_loc = components.manager.registryLocationForSpec(componentFile)
        try:
            m.unregisterSelf(components.manager, componentFile, reg_loc)
        finally:
            self._removeRegistryInfo( reg_loc, componentFile)
        return 1

    def registerDeferredComponents (self, when):
        # bool return
        if xpcom.verbose:
            print "Python component loader - registerDeferred() called"
        return 0 # no more to register
    def unloadAll (self, when):
        if xpcom.verbose:
            print "Python component loader being asked to unload all components!"
        self.registry = None
        self.comp_mgr = None
        self.com_modules = {}
    # Internal Helpers
    def _setRegistryInfo(self, registry_location, nsIFile):
        if self.registry is None:
            return # No registry work allowed.
        e_location = self.registry.escapeKey(registry_location, 1)
        if e_location is None: # No escaped key needed.
            e_location = registry_location
        key = self.registry.addSubtreeRaw(self.xpcom_registry_key, e_location)
        self.registry.setLongLong(key, lastModValueName, nsIFile.lastModifiedTime)
        self.registry.setLongLong(key, fileSizeValueName, nsIFile.fileSize)
    def _hasChanged(self, registry_location, nsIFile):
        if self.registry is None:
            # Can't cache in registry - assume it has changed.
            return 1
        e_location = self.registry.escapeKey(registry_location, 1)
        if e_location is None: # No escaped key needed.
            e_location = registry_location
        try:
            key = self.registry.getSubtreeRaw(self.xpcom_registry_key, e_location)
            if nsIFile.lastModifiedTime != self.registry.getLongLong(key, lastModValueName):
                return 1
            if nsIFile.fileSize != self.registry.getLongLong(key, fileSizeValueName):
                return 1
            return 0
        except xpcom.Exception, details:
            return 1

    def _removeRegistryInfo(self, registry_location, nsIFile):
        if self.registry is None:
            return # No registry work allowed.
        e_location = self.registry.escapeKey(registry_location, 1)
        if e_location is None: # No escaped key needed.
            e_location = registry_location
        try:
            key = self.registry.removeSubtreeRaw(self.xpcom_registry_key, e_location)
        except xpcom.Exception, details:
            pass

def MakePythonComponentLoaderModule(serviceManager, nsIFile):
    import module
    return module.Module( [PythonComponentLoader] )