From c87a2794449b69eec4489b5f291188938e8e3d3c Mon Sep 17 00:00:00 2001
From: Marc Zinnschlag <marc@zpages.de>
Date: Sun, 18 Aug 2013 17:54:18 +0200
Subject: [PATCH] added error reporting in the filter edit widget (change the
 text colour for now)

---
 apps/opencs/model/filter/parser.cpp    | 50 ++++++++++++++++++++++++--
 apps/opencs/model/filter/parser.hpp    |  8 +++++
 apps/opencs/view/filter/editwidget.cpp | 10 +++++-
 apps/opencs/view/filter/editwidget.hpp |  2 ++
 4 files changed, 66 insertions(+), 4 deletions(-)

diff --git a/apps/opencs/model/filter/parser.cpp b/apps/opencs/model/filter/parser.cpp
index 46052cec67..06a974bbe8 100644
--- a/apps/opencs/model/filter/parser.cpp
+++ b/apps/opencs/model/filter/parser.cpp
@@ -5,6 +5,37 @@
 
 #include "booleannode.hpp"
 
+namespace CSMFilter
+{
+    struct Token
+    {
+        enum Type
+        {
+            Type_EOS,
+            Type_None
+        };
+
+        Type mType;
+
+        Token (Type type);
+    };
+
+    Token::Token (Type type) : mType (type) {}
+}
+
+CSMFilter::Token CSMFilter::Parser::getNextToken (const std::string& filter, int& index) const
+{
+    if (index>=static_cast<int> (filter.size()))
+        return Token (Token::Type_EOS);
+
+    return Token (Token::Type_None);
+}
+
+bool CSMFilter::Parser::isEndState() const
+{
+    return mState==State_End || mState==State_UnexpectedCharacter;
+}
+
 CSMFilter::Parser::Parser() : mState (State_Begin) {}
 
 void CSMFilter::Parser::parse (const std::string& filter)
@@ -12,11 +43,24 @@ void CSMFilter::Parser::parse (const std::string& filter)
     // reset
     mState = State_Begin;
     mFilter.reset();
+    int index = 0;
 
+    while (!isEndState())
+    {
+        Token token = getNextToken (filter, index);
 
-    // for now we ignore the filter string
-    mFilter.reset (new BooleanNode (false));
-    mState = State_End;
+        switch (token.mType)
+        {
+            case Token::Type_None: mState = State_UnexpectedCharacter; break;
+            case Token::Type_EOS: mState = State_End; break;
+        }
+    }
+
+    if (mState==State_End && !mFilter)
+    {
+        // Empty filter string equals to filter "true".
+        mFilter.reset (new BooleanNode (true));
+    }
 }
 
 CSMFilter::Parser::State CSMFilter::Parser::getState() const
diff --git a/apps/opencs/model/filter/parser.hpp b/apps/opencs/model/filter/parser.hpp
index 72dc7d507d..2d616b9e1b 100644
--- a/apps/opencs/model/filter/parser.hpp
+++ b/apps/opencs/model/filter/parser.hpp
@@ -7,6 +7,8 @@
 
 namespace CSMFilter
 {
+    struct Token;
+
     class Parser
     {
         public:
@@ -14,6 +16,7 @@ namespace CSMFilter
             enum State
             {
                 State_Begin,
+                State_UnexpectedCharacter,
                 State_End
             };
 
@@ -22,6 +25,11 @@ namespace CSMFilter
             State mState;
             boost::shared_ptr<Node> mFilter;
 
+            Token getNextToken (const std::string& filter, int& index) const;
+
+            bool isEndState() const;
+            ///< This includes error states.
+
         public:
 
             Parser();
diff --git a/apps/opencs/view/filter/editwidget.cpp b/apps/opencs/view/filter/editwidget.cpp
index b8853ffa35..79cbc1dcea 100644
--- a/apps/opencs/view/filter/editwidget.cpp
+++ b/apps/opencs/view/filter/editwidget.cpp
@@ -4,6 +4,7 @@
 CSVFilter::EditWidget::EditWidget (QWidget *parent)
 : QLineEdit (parent)
 {
+    mPalette = palette();
     connect (this, SIGNAL (textChanged (const QString&)), this, SLOT (textChanged (const QString&)));
 }
 
@@ -12,9 +13,16 @@ void CSVFilter::EditWidget::textChanged (const QString& text)
     mParser.parse (text.toUtf8().constData());
 
     if (mParser.getState()==CSMFilter::Parser::State_End)
+    {
+        setPalette (mPalette);
         emit filterChanged (mParser.getFilter(), "");
+    }
     else
     {
-        /// \todo error handling
+        QPalette palette (mPalette);
+        palette.setColor (QPalette::Text, Qt::red);
+        setPalette (palette);
+
+        /// \todo improve error reporting; mark only the faulty part
     }
 }
\ No newline at end of file
diff --git a/apps/opencs/view/filter/editwidget.hpp b/apps/opencs/view/filter/editwidget.hpp
index 9c4b1fa161..4e692fc4d8 100644
--- a/apps/opencs/view/filter/editwidget.hpp
+++ b/apps/opencs/view/filter/editwidget.hpp
@@ -4,6 +4,7 @@
 #include <boost/shared_ptr.hpp>
 
 #include <QLineEdit>
+#include <QPalette>
 
 #include "../../model/filter/parser.hpp"
 #include "../../model/filter/node.hpp"
@@ -15,6 +16,7 @@ namespace CSVFilter
             Q_OBJECT
 
             CSMFilter::Parser mParser;
+            QPalette mPalette;
 
         public: