Moved most of the python support code to a new module qgis.utils

This will enable more flexibility in plugins handling
Hopefully it doesn't break anything :-)


git-svn-id: http://svn.osgeo.org/qgis/trunk@11950 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: wonder

python/CMakeLists.txt

@@ -89,5 +89,5 @@ ENDIF (BINDINGS_GLOBAL_INSTALL)
 
 
 # Step 4: install built libs to python's site packages
-INSTALL(FILES __init__.py ${CMAKE_CURRENT_BINARY_DIR}/qgisconfig.py ${BINDINGS_LIBS} DESTINATION ${SITE_PKG_PATH}/qgis)
+INSTALL(FILES __init__.py utils.py ${CMAKE_CURRENT_BINARY_DIR}/qgisconfig.py ${BINDINGS_LIBS} DESTINATION ${SITE_PKG_PATH}/qgis)
 

python/utils.py

@@ -0,0 +1,160 @@
+"""
+QGIS utilities module
+
+"""
+
+from PyQt4.QtCore import QCoreApplication
+import sys
+import traceback
+
+
+#######################
+# ERROR HANDLING
+
+def showException(type, value, tb, msg):
+  lst = traceback.format_exception(type, value, tb)
+  if msg == None:
+    msg = QCoreApplication.translate('Python', 'An error has occured while executing Python code:')
+  txt = '<font color="red">%s</font><br><br>' % msg
+  for s in lst:
+    txt += s
+  txt += '<br>%s<br>%s<br><br>' % (QCoreApplication.translate('Python','Python version:'), sys.version)
+  txt += '%s %s' % (QCoreApplication.translate('Python','Python path:'), str(sys.path))
+  txt = txt.replace('\n', '<br>')
+  txt = txt.replace('  ', '&nbsp; ') # preserve whitespaces for nicer output
+
+  from qgis.core import QgsMessageOutput
+  msg = QgsMessageOutput.createMessageOutput()
+  msg.setTitle(QCoreApplication.translate('Python', 'Python error'))
+  msg.setMessage(txt, QgsMessageOutput.MessageHtml)
+  msg.showMessage()
+
+def qgis_excepthook(type, value, tb):
+  showException(type, value, tb, None)
+
+def installErrorHook():
+  sys.excepthook = qgis_excepthook
+
+def uninstallErrorHook():
+  sys.excepthook = sys.__excepthook__
+
+# install error hook() on module load
+installErrorHook()
+
+# initialize 'iface' object
+iface = None
+
+def initInterface(pointer):
+  from qgis.gui import QgisInterface
+  from sip import wrapinstance
+  global iface
+  iface = wrapinstance(pointer, QgisInterface)
+
+
+#######################
+# CONSOLE OUTPUT
+
+old_stdout = sys.stdout
+console_output = None
+
+# hook for python console so all output will be redirected
+# and then shown in console
+def console_displayhook(obj):
+  console_output = obj
+
+class QgisOutputCatcher:
+  def __init__(self):
+    self.data = ''
+  def write(self, stuff):
+    self.data += stuff
+  def get_and_clean_data(self):
+    tmp = self.data
+    self.data = ''
+    return tmp
+
+def installConsoleHooks():
+  sys.displayhook = console_displayhook
+  sys.stdout = QgisOutputCatcher()
+
+def uninstallConsoleHooks():
+  sys.displayhook = sys.__displayhook__
+  sys.stdout = old_stdout
+
+
+#######################
+# PLUGINS
+
+# dictionary of plugins
+plugins = {}
+
+def pluginMetadata(packageName, fct):
+  """ fetch metadata from a plugin """
+  try:
+    package = sys.modules[packageName]
+    return getattr(package, fct)()
+  except:
+    return "__error__"
+
+def loadPlugin(packageName):
+  """ load plugin's package and ensure that plugin is reloaded when changed """
+
+  try:
+    __import__(packageName)
+    return True
+  except:
+    pass # continue...
+
+  # snake in the grass, we know it's there
+  sys.path_importer_cache.clear()
+
+  # retry
+  try:
+    __import__(packageName)
+    reload(packageName)
+    return True
+  except:
+    msgTemplate = QCoreApplication.translate("Python", "Couldn't load plugin '%1' from ['%2']")
+    msg = msgTemplate.arg(packageName).arg("', '".join(sys.path))
+    showException(sys.exc_type, sys.exc_value, sys.exc_traceback, msg)
+    return False
+
+
+def startPlugin(packageName):
+  """ initialize the plugin """
+  global plugins, iface
+
+  package = sys.modules[packageName]
+
+  errMsg = QCoreApplication.translate("Python", "Couldn't load plugin %1" ).arg(packageName)
+
+  # create an instance of the plugin
+  try:
+    plugins[packageName] = package.classFactory(iface)
+  except:
+    msg = QCoreApplication.translate("Python", "%1 due an error when calling its classFactory() method").arg(errMsg)
+    showException(sys.exc_type, sys.exc_value, sys.exc_traceback, msg)
+    return False
+
+  # initGui
+  try:
+    plugins[packageName].initGui()
+  except:
+    msg = QCoreApplication.translate("Python", "%1 due an error when calling its initGui() method" ).arg( errMsg )
+    showException(sys.exc_type, sys.exc_value, sys.exc_traceback, msg)
+    return False
+
+  return True
+
+
+def unloadPlugin(packageName):
+  """ unload and delete plugin! """
+  global plugins
+
+  try:
+    plugins[packageName].unload()
+    del plugins[packageName]
+    return True
+  except Exception, e:
+    errMsg = QCoreApplication.translate("Python", "Error while unloading plugin %1").arg(packageName)
+    showException(sys.exc_type, sys.exc_value, sys.exc_traceback, msg)
+    return False