[pyqgis] move qgis.core tricks to their own python file in additions folder

this makes the code much easier to read

python/core/__init__.py

@@ -16,8 +16,6 @@
 *                                                                         *
 ***************************************************************************
 """
-from builtins import str
-from builtins import object
 
 __author__ = 'Nathan Woodrow'
 __date__ = 'May 2014'
@@ -25,341 +23,25 @@ __copyright__ = '(C) 2014, Nathan Woodrow'
 # This will get replaced with a git SHA1 when you do a git archive
 __revision__ = '$Format:%H$'
 
-from qgis.PyQt.QtCore import QCoreApplication, NULL
 
-import inspect
-import string
-import types
-import functools
 from qgis._core import *
 
+from .additions.readwritecontextentercategory import ReadWriteContextEnterCategory
+from .additions.projectdirtyblocker import ProjectDirtyBlocker
+from .additions.qgstaskwrapper import QgsTaskWrapper
+from .additions.qgsfunction import register_function, qgsfunction
+from .additions.edit import edit, QgsEditError
+from .additions.fromfunction import fromFunction
+from .additions.processing import processing_output_layer_repr, processing_source_repr
+from .additions.qgsgeometry import _geometryNonZero
+from .additions.qgsdefaultvalue import _isValid
 
-# Boolean evaluation of QgsGeometry
+# Injections into classes
-
-
-def _geometryNonZero(self):
-    return not self.isEmpty()
-
-
-def _isValid(self):
-    return self.isValid()
-
-
 QgsGeometry.__nonzero__ = _geometryNonZero
 QgsGeometry.__bool__ = _geometryNonZero
-
 QgsDefaultValue.__bool__ = _isValid
-
-
-def register_function(function, arg_count, group, usesgeometry=False,
-                      referenced_columns=[QgsFeatureRequest.ALL_ATTRIBUTES], **kwargs):
-    """
-    Register a Python function to be used as a expression function.
-
-    Functions should take (values, feature, parent) as args:
-
-    Example:
-        def myfunc(values, feature, parent):
-            pass
-
-    They can also shortcut naming feature and parent args by using *args
-    if they are not needed in the function.
-
-    Example:
-        def myfunc(values, *args):
-            pass
-
-    Functions should return a value compatible with QVariant
-
-    Eval errors can be raised using parent.setEvalErrorString("Error message")
-
-    :param function:
-    :param arg_count:
-    :param group:
-    :param usesgeometry:
-    :return:
-    """
-
-    class QgsPyExpressionFunction(QgsExpressionFunction):
-
-        def __init__(self, func, name, args, group, helptext='', usesGeometry=True,
-                     referencedColumns=QgsFeatureRequest.ALL_ATTRIBUTES, expandargs=False):
-            QgsExpressionFunction.__init__(self, name, args, group, helptext)
-            self.function = func
-            self.expandargs = expandargs
-            self.uses_geometry = usesGeometry
-            self.referenced_columns = referencedColumns
-
-        def func(self, values, context, parent, node):
-            feature = None
-            if context:
-                feature = context.feature()
-
-            try:
-                if self.expandargs:
-                    values.append(feature)
-                    values.append(parent)
-                    if inspect.getargspec(self.function).args[-1] == 'context':
-                        values.append(context)
-                    return self.function(*values)
-                else:
-                    if inspect.getargspec(self.function).args[-1] == 'context':
-                        self.function(values, feature, parent, context)
-                    return self.function(values, feature, parent)
-            except Exception as ex:
-                parent.setEvalErrorString(str(ex))
-                return None
-
-        def usesGeometry(self, node):
-            return self.uses_geometry
-
-        def referencedColumns(self, node):
-            return self.referenced_columns
-
-    helptemplate = string.Template("""<h3>$name function</h3><br>$doc""")
-    name = kwargs.get('name', function.__name__)
-    helptext = kwargs.get('helpText') or function.__doc__ or ''
-    helptext = helptext.strip()
-    expandargs = False
-
-    if arg_count == "auto":
-        # Work out the number of args we need.
-        # Number of function args - 2.  The last two args are always feature, parent.
-        args = inspect.getargspec(function).args
-        number = len(args)
-        arg_count = number - 2
-        if args[-1] == 'context':
-            arg_count -= 1
-        expandargs = True
-
-    register = kwargs.get('register', True)
-    if register and QgsExpression.isFunctionName(name):
-        if not QgsExpression.unregisterFunction(name):
-            msgtitle = QCoreApplication.translate("UserExpressions", "User expressions")
-            msg = QCoreApplication.translate("UserExpressions",
-                                             "The user expression {0} already exists and could not be unregistered.").format(
-                name)
-            QgsMessageLog.logMessage(msg + "\n", msgtitle, Qgis.Warning)
-            return None
-
-    function.__name__ = name
-    helptext = helptemplate.safe_substitute(name=name, doc=helptext)
-    f = QgsPyExpressionFunction(function, name, arg_count, group, helptext, usesgeometry, referenced_columns,
-                                expandargs)
-
-    # This doesn't really make any sense here but does when used from a decorator context
-    # so it can stay.
-    if register:
-        QgsExpression.registerFunction(f)
-    return f
-
-
-def qgsfunction(args='auto', group='custom', **kwargs):
-    """
-    Decorator function used to define a user expression function.
-
-    Example:
-      @qgsfunction(2, 'test'):
-      def add(values, feature, parent):
-        pass
-
-    Will create and register a function in QgsExpression called 'add' in the
-    'test' group that takes two arguments.
-
-    or not using feature and parent:
-
-    Example:
-      @qgsfunction(2, 'test'):
-      def add(values, *args):
-        pass
-    """
-
-    def wrapper(func):
-        return register_function(func, args, group, **kwargs)
-
-    return wrapper
-
-
-class QgsEditError(Exception):
-
-    def __init__(self, value):
-        self.value = value
-
-    def __str__(self):
-        return repr(self.value)
-
-
-# Define a `with edit(layer)` statement
-
-
-class edit(object):
-
-    def __init__(self, layer):
-        self.layer = layer
-
-    def __enter__(self):
-        assert self.layer.startEditing()
-        return self.layer
-
-    def __exit__(self, ex_type, ex_value, traceback):
-        if ex_type is None:
-            if not self.layer.commitChanges():
-                raise QgsEditError(self.layer.commitErrors())
-            return True
-        else:
-            self.layer.rollBack()
-            return False
-
-# Python class to mimic QgsReadWriteContextCategoryPopper C++ class
-
-
-class ReadWriteContextEnterCategory():
-    """
-    Push a category to the stack
-
-    .. code-block:: python
-
-        context = QgsReadWriteContext()
-        with QgsReadWriteContext.enterCategory(context, category, details):
-            # do something
-
-    .. versionadded:: 3.2
-    """
-
-    def __init__(self, context, category_name, details=None):
-        self.context = context
-        self.category_name = category_name
-        self.details = details
-        self.popper = None
-
-    def __enter__(self):
-        self.popper = self.context._enterCategory(self.category_name, self.details)
-        return self.context
-
-    def __exit__(self, ex_type, ex_value, traceback):
-        del self.popper
-        return True
-
-
-# Inject the context manager into QgsReadWriteContext class as a member
 QgsReadWriteContext.enterCategory = ReadWriteContextEnterCategory
-
-
-# Python class to extend QgsProjectDirtyBlocker C++ class
-
-
-class ProjectDirtyBlocker():
-    """
-    Context manager used to block project setDirty calls.
-
-    .. code-block:: python
-
-        project = QgsProject.instance()
-        with QgsProject.blockDirtying(project):
-            # do something
-
-    .. versionadded:: 3.2
-    """
-
-    def __init__(self, project):
-        self.project = project
-        self.blocker = None
-
-    def __enter__(self):
-        self.blocker = QgsProjectDirtyBlocker(self.project)
-        return self.project
-
-    def __exit__(self, ex_type, ex_value, traceback):
-        del self.blocker
-        return True
-
-
-# Inject the context manager into QgsProject class as a member
 QgsProject.blockDirtying = ProjectDirtyBlocker
-
-
-class QgsTaskWrapper(QgsTask):
-
-    def __init__(self, description, flags, function, on_finished, *args, **kwargs):
-        QgsTask.__init__(self, description, flags)
-        self.args = args
-        self.kwargs = kwargs
-        self.function = function
-        self.on_finished = on_finished
-        self.returned_values = None
-        self.exception = None
-
-    def run(self):
-        try:
-            self.returned_values = self.function(self, *self.args, **self.kwargs)
-        except Exception as ex:
-            # report error
-            self.exception = ex
-            return False
-
-        return True
-
-    def finished(self, result):
-        if not self.on_finished:
-            return
-
-        if not result and self.exception is None:
-            self.exception = Exception('Task canceled')
-
-        try:
-            if self.returned_values:
-                self.on_finished(self.exception, self.returned_values)
-            else:
-                self.on_finished(self.exception)
-        except Exception as ex:
-            self.exception = ex
-
-
-@staticmethod
-def fromFunction(description, function, *args, on_finished=None, flags=QgsTask.AllFlags, **kwargs):
-    """
-    Creates a new QgsTask task from a python function.
-
-    Example:
-
-    def calculate(task):
-        # pretend this is some complex maths and stuff we want
-        # to run in the background
-        return 5*6
-
-    def calculation_finished(exception, value=None):
-        if not exception:
-            iface.messageBar().pushMessage(
-                'the magic number is {}'.format(value))
-        else:
-            iface.messageBar().pushMessage(
-                str(exception))
-
-    task = QgsTask.fromFunction('my task', calculate,
-            on_finished=calculation_finished)
-    QgsApplication.taskManager().addTask(task)
-
-    """
-
-    assert function
-    return QgsTaskWrapper(description, flags, function, on_finished, *args, **kwargs)
-
-
 QgsTask.fromFunction = fromFunction
-
-
-# add some __repr__ methods to processing classes
-def processing_source_repr(self):
-    return "<QgsProcessingFeatureSourceDefinition {{'source':{}, 'selectedFeaturesOnly': {}}}>".format(
-        self.source.staticValue(), self.selectedFeaturesOnly)
-
-
 QgsProcessingFeatureSourceDefinition.__repr__ = processing_source_repr
-
-
-def processing_output_layer_repr(self):
-    return "<QgsProcessingOutputLayerDefinition {{'sink':{}, 'createOptions': {}}}>".format(self.sink.staticValue(),
-                                                                                            self.createOptions)
-
-
 QgsProcessingOutputLayerDefinition.__repr__ = processing_output_layer_repr

python/core/additions/edit.py

@@ -0,0 +1,48 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    edit.py
+    ---------------------
+    Date                 : May 2018
+    Copyright            : (C) 2018 by Denis Rouzaud
+    Email                : denis@opengis.ch
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+from builtins import object
+
+
+class QgsEditError(Exception):
+
+    def __init__(self, value):
+        self.value = value
+
+    def __str__(self):
+        return repr(self.value)
+
+
+class edit(object):
+
+    def __init__(self, layer):
+        self.layer = layer
+
+    def __enter__(self):
+        assert self.layer.startEditing()
+        return self.layer
+
+    def __exit__(self, ex_type, ex_value, traceback):
+        if ex_type is None:
+            if not self.layer.commitChanges():
+                raise QgsEditError(self.layer.commitErrors())
+            return True
+        else:
+            self.layer.rollBack()
+            return False

python/core/additions/fromfunction.py

@@ -0,0 +1,51 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    fromfunction.py
+    ---------------------
+    Date                 : May 2018
+    Copyright            : (C) 2018 by Denis Rouzaud
+    Email                : denis@opengis.ch
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+from .qgstaskwrapper import QgsTaskWrapper
+from qgis._core import QgsTask
+
+
+@staticmethod
+def fromFunction(description, function, *args, on_finished=None, flags=QgsTask.AllFlags, **kwargs):
+    """
+    Creates a new QgsTask task from a python function.
+
+    Example:
+
+    def calculate(task):
+        # pretend this is some complex maths and stuff we want
+        # to run in the background
+        return 5*6
+
+    def calculation_finished(exception, value=None):
+        if not exception:
+            iface.messageBar().pushMessage(
+                'the magic number is {}'.format(value))
+        else:
+            iface.messageBar().pushMessage(
+                str(exception))
+
+    task = QgsTask.fromFunction('my task', calculate,
+            on_finished=calculation_finished)
+    QgsApplication.taskManager().addTask(task)
+
+    """
+
+    assert function
+    return QgsTaskWrapper(description, flags, function, on_finished, *args, **kwargs)

python/core/additions/processing.py

@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    processing.py
+    ---------------------
+    Date                 : May 2018
+    Copyright            : (C) 2018 by Denis Rouzaud
+    Email                : denis@opengis.ch
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+
+# add some __repr__ methods to processing classes
+def processing_source_repr(self):
+    return "<QgsProcessingFeatureSourceDefinition {{'source':{}, 'selectedFeaturesOnly': {}}}>".format(
+        self.source.staticValue(), self.selectedFeaturesOnly)
+
+
+def processing_output_layer_repr(self):
+    return "<QgsProcessingOutputLayerDefinition {{'sink':{}, 'createOptions': {}}}>".format(self.sink.staticValue(),
+                                                                                            self.createOptions)

python/core/additions/projectdirtyblocker.py

@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    projectdirtyblocker.py
+    ---------------------
+    Date                 : May 2018
+    Copyright            : (C) 2018 by Denis Rouzaud
+    Email                : denis@opengis.ch
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+
+from qgis._core import QgsProjectDirtyBlocker
+
+
+class ProjectDirtyBlocker():
+    """
+    Context manager used to block project setDirty calls.
+
+    .. code-block:: python
+
+        project = QgsProject.instance()
+        with QgsProject.blockDirtying(project):
+            # do something
+
+    .. versionadded:: 3.2
+    """
+
+    def __init__(self, project):
+        self.project = project
+        self.blocker = None
+
+    def __enter__(self):
+        self.blocker = QgsProjectDirtyBlocker(self.project)
+        return self.project
+
+    def __exit__(self, ex_type, ex_value, traceback):
+        del self.blocker
+        return True

python/core/additions/qgsdefaultvalue.py

@@ -0,0 +1,22 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    qgsdefaultvalue.py
+    ---------------------
+    Date                 : May 2018
+    Copyright            : (C) 2018 by Denis Rouzaud
+    Email                : denis@opengis.ch
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+
+def _isValid(self):
+    return self.isValid()

python/core/additions/qgsfunction.py

@@ -0,0 +1,154 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    qgsfunction.py
+    ---------------------
+    Date                 : May 2018
+    Copyright            : (C) 2018 by Denis Rouzaud
+    Email                : denis@opengis.ch
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+
+import inspect
+import string
+from builtins import str
+from qgis.PyQt.QtCore import QCoreApplication
+from qgis._core import QgsExpressionFunction, QgsExpression, QgsMessageLog, QgsFeatureRequest
+
+
+def register_function(function, arg_count, group, usesgeometry=False,
+                      referenced_columns=[QgsFeatureRequest.ALL_ATTRIBUTES], **kwargs):
+    """
+    Register a Python function to be used as a expression function.
+
+    Functions should take (values, feature, parent) as args:
+
+    Example:
+        def myfunc(values, feature, parent):
+            pass
+
+    They can also shortcut naming feature and parent args by using *args
+    if they are not needed in the function.
+
+    Example:
+        def myfunc(values, *args):
+            pass
+
+    Functions should return a value compatible with QVariant
+
+    Eval errors can be raised using parent.setEvalErrorString("Error message")
+
+    :param function:
+    :param arg_count:
+    :param group:
+    :param usesgeometry:
+    :return:
+    """
+
+    class QgsPyExpressionFunction(QgsExpressionFunction):
+
+        def __init__(self, func, name, args, group, helptext='', usesGeometry=True,
+                     referencedColumns=QgsFeatureRequest.ALL_ATTRIBUTES, expandargs=False):
+            QgsExpressionFunction.__init__(self, name, args, group, helptext)
+            self.function = func
+            self.expandargs = expandargs
+            self.uses_geometry = usesGeometry
+            self.referenced_columns = referencedColumns
+
+        def func(self, values, context, parent, node):
+            feature = None
+            if context:
+                feature = context.feature()
+
+            try:
+                if self.expandargs:
+                    values.append(feature)
+                    values.append(parent)
+                    if inspect.getargspec(self.function).args[-1] == 'context':
+                        values.append(context)
+                    return self.function(*values)
+                else:
+                    if inspect.getargspec(self.function).args[-1] == 'context':
+                        self.function(values, feature, parent, context)
+                    return self.function(values, feature, parent)
+            except Exception as ex:
+                parent.setEvalErrorString(str(ex))
+                return None
+
+        def usesGeometry(self, node):
+            return self.uses_geometry
+
+        def referencedColumns(self, node):
+            return self.referenced_columns
+
+    helptemplate = string.Template("""<h3>$name function</h3><br>$doc""")
+    name = kwargs.get('name', function.__name__)
+    helptext = kwargs.get('helpText') or function.__doc__ or ''
+    helptext = helptext.strip()
+    expandargs = False
+
+    if arg_count == "auto":
+        # Work out the number of args we need.
+        # Number of function args - 2.  The last two args are always feature, parent.
+        args = inspect.getargspec(function).args
+        number = len(args)
+        arg_count = number - 2
+        if args[-1] == 'context':
+            arg_count -= 1
+        expandargs = True
+
+    register = kwargs.get('register', True)
+    if register and QgsExpression.isFunctionName(name):
+        if not QgsExpression.unregisterFunction(name):
+            msgtitle = QCoreApplication.translate("UserExpressions", "User expressions")
+            msg = QCoreApplication.translate("UserExpressions",
+                                             "The user expression {0} already exists and could not be unregistered.").format(
+                name)
+            QgsMessageLog.logMessage(msg + "\n", msgtitle, Qgis.Warning)
+            return None
+
+    function.__name__ = name
+    helptext = helptemplate.safe_substitute(name=name, doc=helptext)
+    f = QgsPyExpressionFunction(function, name, arg_count, group, helptext, usesgeometry, referenced_columns,
+                                expandargs)
+
+    # This doesn't really make any sense here but does when used from a decorator context
+    # so it can stay.
+    if register:
+        QgsExpression.registerFunction(f)
+    return f
+
+
+def qgsfunction(args='auto', group='custom', **kwargs):
+    """
+    Decorator function used to define a user expression function.
+
+    Example:
+      @qgsfunction(2, 'test'):
+      def add(values, feature, parent):
+        pass
+
+    Will create and register a function in QgsExpression called 'add' in the
+    'test' group that takes two arguments.
+
+    or not using feature and parent:
+
+    Example:
+      @qgsfunction(2, 'test'):
+      def add(values, *args):
+        pass
+    """
+
+    def wrapper(func):
+        return register_function(func, args, group, **kwargs)
+
+    return wrapper

python/core/additions/qgsgeometry.py

@@ -0,0 +1,22 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    qgsgeometry.py
+    ---------------------
+    Date                 : May 2018
+    Copyright            : (C) 2018 by Denis Rouzaud
+    Email                : denis@opengis.ch
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+
+def _geometryNonZero(self):
+    return not self.isEmpty()

python/core/additions/qgstaskwrapper.py

@@ -0,0 +1,58 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    qgstaskwrapper.py
+    ---------------------
+    Date                 : May 2018
+    Copyright            : (C) 2018 by Denis Rouzaud
+    Email                : denis@opengis.ch
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+
+from qgis._core import QgsTask
+
+
+class QgsTaskWrapper(QgsTask):
+
+    def __init__(self, description, flags, function, on_finished, *args, **kwargs):
+        QgsTask.__init__(self, description, flags)
+        self.args = args
+        self.kwargs = kwargs
+        self.function = function
+        self.on_finished = on_finished
+        self.returned_values = None
+        self.exception = None
+
+    def run(self):
+        try:
+            self.returned_values = self.function(self, *self.args, **self.kwargs)
+        except Exception as ex:
+            # report error
+            self.exception = ex
+            return False
+
+        return True
+
+    def finished(self, result):
+        if not self.on_finished:
+            return
+
+        if not result and self.exception is None:
+            self.exception = Exception('Task canceled')
+
+        try:
+            if self.returned_values:
+                self.on_finished(self.exception, self.returned_values)
+            else:
+                self.on_finished(self.exception)
+        except Exception as ex:
+            self.exception = ex

python/core/additions/readwritecontextentercategory.py

@@ -0,0 +1,46 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    readwritecontextentercategory.py
+    ---------------------
+    Date                 : May 2018
+    Copyright            : (C) 2018 by Denis Rouzaud
+    Email                : denis@opengis.ch
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+
+class ReadWriteContextEnterCategory():
+    """
+    Push a category to the stack
+
+    .. code-block:: python
+
+        context = QgsReadWriteContext()
+        with QgsReadWriteContext.enterCategory(context, category, details):
+            # do something
+
+    .. versionadded:: 3.2
+    """
+
+    def __init__(self, context, category_name, details=None):
+        self.context = context
+        self.category_name = category_name
+        self.details = details
+        self.popper = None
+
+    def __enter__(self):
+        self.popper = self.context._enterCategory(self.category_name, self.details)
+        return self.context
+
+    def __exit__(self, ex_type, ex_value, traceback):
+        del self.popper
+        return True