- improved error handling when loading python plugins

- redirection of output to python console, i.e. print command works


git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@6767 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: wonder

src/app/qgisapp.cpp

@@ -1531,6 +1531,7 @@ void QgisApp::restoreSessionPlugins(QString thePluginDirString)
   }
 
 #ifdef HAVE_PYTHON
+  QString pluginName, description, version;
 
   if (QgsPythonUtils::isEnabled())
   {
@@ -1544,12 +1545,18 @@ void QgisApp::restoreSessionPlugins(QString thePluginDirString)
       QString packageName = pluginDir[i];
 
       // import plugin's package
-      QgsPythonUtils::loadPlugin(packageName);
+      if (!QgsPythonUtils::loadPlugin(packageName))
+        continue;
 
       // get information from the plugin
-      QString pluginName  = QgsPythonUtils::getPluginMetadata(packageName, "name");
-      QString description = QgsPythonUtils::getPluginMetadata(packageName, "description");
-      QString version     = QgsPythonUtils::getPluginMetadata(packageName, "version");
+      // if there are some problems, don't continue with metadata retreival
+      pluginName = QgsPythonUtils::getPluginMetadata(packageName, "name");
+      if (pluginName != "__error__")
+      {
+        description = QgsPythonUtils::getPluginMetadata(packageName, "description");
+        if (description != "__error__")
+          version = QgsPythonUtils::getPluginMetadata(packageName, "version");
+      }
 
       if (pluginName == "__error__" || description == "__error__" || version == "__error__")
       {

src/app/qgspythondialog.cpp

@@ -17,8 +17,6 @@
 #include "qgspythondialog.h"
 #include "qgspythonutils.h"
 
-#include <iostream> // %%%
-
 
 QgsPythonDialog::QgsPythonDialog(QgisInterface* pIface, QWidget *parent)
   : QDialog(parent)
@@ -43,7 +41,10 @@ void QgsPythonDialog::on_edtCmdLine_returnPressed()
   // we're using custom hooks for output and exceptions to show output in console
   if (QgsPythonUtils::runString(command))
   {
-    output = QgsPythonUtils::getResult();
+    QgsPythonUtils::evalString("sys.stdout.data", output);
+    QgsPythonUtils::runString("sys.stdout.data = ''");
+    
+    output += QgsPythonUtils::getResult();
 
     if (!output.isEmpty())
       output += "<br>";

src/app/qgspythonutils.cpp

@@ -22,7 +22,6 @@
 
 #include "qgsapplication.h"
 
-
 #include <QMessageBox>
 
 QString QgsPythonUtils::mPluginsPath;
@@ -84,9 +83,10 @@ void QgsPythonUtils::initPython(QgisInterface* interface)
 
   // hook that will show information and traceback in message box
   runString(
-      "def qgis_except_hook(type, value, tb):\n"
+      "def qgis_except_hook_msg(type, value, tb, msg):\n"
       "  lst = traceback.format_exception(type, value, tb)\n"
-      "  str = '<font color=\"red\">An error has occured while executing Python code:</font><br><br>'\n"
+      "  if msg == None: msg = 'An error has occured while executing Python code:'\n"
+      "  str = '<font color=\"red\">'+msg+'</font><br><br>'\n"
       "  for s in lst:\n"
       "    str += s\n"
       "  str = str.replace('\\n', '<br>')\n"
@@ -96,6 +96,9 @@ void QgsPythonUtils::initPython(QgisInterface* interface)
       "  msg.setTitle('Error')\n"
       "  msg.setMessage(str, QgsMessageOutput.MessageHtml)\n"
       "  msg.showMessage()\n");
+  runString(
+      "def qgis_except_hook(type, value, tb):\n"
+      "  qgis_except_hook_msg(type, value, tb, None)\n");
 
   // hook for python console so all output will be redirected
   // and then shown in console
@@ -132,17 +135,31 @@ void QgsPythonUtils::installErrorHook()
 
 void QgsPythonUtils::installConsoleHooks()
 {
-  runString("sys.displayhook = console_display_hook");
+  runString("sys.displayhook = console_display_hook\n");
+  
+  runString(
+    "class MyOutputCatcher:\n"
+    "  def __init__(self):\n"
+    "    self.data = ''\n"
+    "  def write(self, stuff):\n"
+    "    self.data += stuff\n");
+  runString("_old_stdout = sys.stdout\n");
+  runString("sys.stdout = MyOutputCatcher()\n");
+  
 }
 
 void QgsPythonUtils::uninstallConsoleHooks()
 {
   runString("sys.displayhook = sys.__displayhook__");
+  runString("sys.stdout = _old_stdout");
+  
+  // TODO: uninstalling stdout redirection doesn't work
+
   //installErrorHook();
 }
 
 
-bool QgsPythonUtils::runString(QString command)
+bool QgsPythonUtils::runString(const QString& command)
 {
   PyRun_String(command.toLocal8Bit().data(), Py_single_input, mMainDict, mMainDict);
 
@@ -183,15 +200,20 @@ bool QgsPythonUtils::getError(QString& errorClassName, QString& errorText)
 }
 
 QString QgsPythonUtils::getResult()
+{
+  return getVariableFromMain("__result");
+}
+
+QString QgsPythonUtils::getVariableFromMain(QString name)
 {
   PyObject* obj;
   PyObject* obj_str;
 
   QString output;
 
   // get the result
-  obj = PyDict_GetItemString(mMainDict, "__result"); // obj is borrowed reference
-    
+  obj = PyDict_GetItemString(mMainDict, name); // obj is borrowed reference
+  
   if (obj != NULL && obj != Py_None)
   {
     obj_str = PyObject_Str(obj); // obj_str is new reference
@@ -203,11 +225,25 @@ QString QgsPythonUtils::getResult()
   }
 
   // erase result
-  PyDict_SetItemString(mMainDict, "__result", Py_None);
-
+  PyDict_SetItemString(mMainDict, name, Py_None);
+  
   return output;
 }
 
+bool QgsPythonUtils::evalString(const QString& command, QString& result)
+{
+  PyObject* res = PyRun_String(command.toLocal8Bit().data(), Py_eval_input, mMainDict, mMainDict);
+  
+  if (res != NULL && PyString_Check(res))
+  {
+    result = PyString_AsString(res);
+    Py_XDECREF(res);
+    return true;
+  }
+  Py_XDECREF(res);
+  return false;
+}
+
 
 QString QgsPythonUtils::pythonPath()
 {
@@ -248,19 +284,17 @@ QString QgsPythonUtils::getPluginMetadata(QString pluginName, QString function)
 bool QgsPythonUtils::loadPlugin(QString packageName)
 {
   // load plugin's package and ensure that plugin is reloaded when changed
-  if (!runString("import " + packageName) ||
-      !runString("reload(" + packageName + ")"))
-  {
-    QString className, errorText;
-    getError(className, errorText);
-    QString str = className + ": " + errorText;
-    
-    QMessageBox::warning(0, QObject::tr("Python error"),
-                         QObject::tr("Couldn't load plugin due this error:\n") + str);
-    return false;
-  }
-
-  return true;
+  runString(
+       "try:\n"
+       "  import " + packageName + "\n"
+       "  reload(" + packageName + ")\n"
+       "  __main__.__plugin_result = 'OK'\n"
+       "except:\n"
+       "  qgis_except_hook_msg(sys.exc_type, sys.exc_value, sys.exc_traceback, "
+       "                       'Couldn\\'t load plugin \"" + packageName + "\"')\n"
+       "  __main__.__plugin_result = 'ERROR'\n");
+  
+  return (getVariableFromMain("__plugin_result") == "OK");
 }
 
 

src/app/qgspythonutils.h

@@ -53,12 +53,17 @@ class QgsPythonUtils
     //! run a statement (wrapper for PyRun_String)
     //! this command is more advanced as enables error checking etc.
     //! @return true if no error occured
-    static bool runString(QString command);
+    static bool runString(const QString& command);
+    
+    static bool evalString(const QString& command, QString& result);
 
     //! get information about error to the supplied arguments
     //! @return false if there was no python error
     static bool getError(QString& errorClassName, QString& errorText);
 
+    //! get variable from main dictionary
+    static QString getVariableFromMain(QString name);
+
     /* python console related functions */
 
     //! change displayhook and excepthook

src/ui/qgspythondialog.ui

@@ -1,7 +1,4 @@
 <ui version="4.0" >
- <author></author>
- <comment></comment>
- <exportmacro></exportmacro>
  <class>QgsPythonDialog</class>
  <widget class="QDialog" name="QgsPythonDialog" >
   <property name="geometry" >
@@ -47,7 +44,10 @@ p, li { white-space: pre-wrap; }
    <item>
     <widget class="QTextBrowser" name="txtHistory" >
      <property name="html" >
-      <string>&lt;html>&lt;head>&lt;meta name="qrichtext" content="1" />&lt;/head>&lt;body style=" white-space: pre-wrap; font-family:DejaVu Sans Condensed; font-size:10pt; font-weight:400; font-style:normal; text-decoration:none;">&lt;p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;">&lt;/p>&lt;/body>&lt;/html></string>
+      <string>&lt;html>&lt;head>&lt;meta name="qrichtext" content="1" />&lt;style type="text/css">
+p, li { white-space: pre-wrap; }
+&lt;/style>&lt;/head>&lt;body style=" font-family:'DejaVu Sans Condensed'; font-size:9pt; font-weight:400; font-style:normal; text-decoration:none;">
+&lt;p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; font-size:10pt;">&lt;/p>&lt;/body>&lt;/html></string>
      </property>
     </widget>
    </item>
@@ -73,7 +73,10 @@ p, li { white-space: pre-wrap; }
    </item>
   </layout>
  </widget>
- <pixmapfunction></pixmapfunction>
+ <tabstops>
+  <tabstop>edtCmdLine</tabstop>
+  <tabstop>txtHistory</tabstop>
+ </tabstops>
  <resources/>
  <connections/>
 </ui>