[BUGFIX] Expression in like escape % and _

The Expression LIKE binary operator does not care about escape % and _ char.
No-one has already open an issue about it but in the OGC element PropertyIsLike the user can defined is own wild and single char. This mean that QGIS has to escape % and _ if they are not used as wild and single char.

Author: rldhont

resources/function_help/json/ILIKE

@@ -3,16 +3,22 @@
   "type": "operator",
   "description": "Returns 1 if the first parameter matches case-insensitive the supplied pattern. LIKE can be used instead of ILIKE to make the match case-sensitive. Works with numbers also.",
   "arguments": [
-	{"arg":"string/number","description":"string to search"},
-	{"arg":"pattern","description":"pattern to find"}
+    {"arg":"string/number","description":"string to search"},
+    {"arg":"pattern","description":"pattern to find, you can use '%' as a wildcard, '_' as a single char and '\\\\' to escape."}
    ],
   "examples": [
-	{ "expression":"'A' ILIKE 'A'", "returns":"1"},
-	{ "expression":"'A' ILIKE 'a'", "returns":"1"},
-	{ "expression":"'A' ILIKE 'B'", "returns":"0"},
-	{ "expression":"'ABC' ILIKE 'b'", "returns":"0"},
-	{ "expression":"'ABC' ILIKE 'B'", "returns":"0"},
-	{ "expression":"'ABC' ILIKE '%b%'", "returns":"1"},
-	{ "expression":"'ABC' ILIKE '%B%'", "returns":"1"}
+    { "expression":"'A' ILIKE 'A'", "returns":"1"},
+    { "expression":"'A' ILIKE 'a'", "returns":"1"},
+    { "expression":"'A' ILIKE 'B'", "returns":"0"},
+    { "expression":"'ABC' ILIKE 'b'", "returns":"0"},
+    { "expression":"'ABC' ILIKE 'B'", "returns":"0"},
+    { "expression":"'ABC' ILIKE '_b_'", "returns":"1"},
+    { "expression":"'ABC' ILIKE '_B_'", "returns":"1"},
+    { "expression":"'ABCD' ILIKE '_b_'", "returns":"0"},
+    { "expression":"'ABCD' ILIKE '_B_'", "returns":"0"},
+    { "expression":"'ABCD' ILIKE '_b%'", "returns":"1"},
+    { "expression":"'ABCD' ILIKE '_B%'", "returns":"1"},
+    { "expression":"'ABCD' ILIKE '%b%'", "returns":"1"},
+    { "expression":"'ABCD' ILIKE '%B%'", "returns":"1"}
   ]
 }

resources/function_help/json/LIKE

@@ -3,14 +3,19 @@
   "type": "operator",
   "description": "Returns 1 if the first parameter matches the supplied pattern. Works with numbers also.",
   "arguments": [
-	{"arg":"string/number","description":"value"},
-	{"arg":"pattern","description":"pattern to compare value with"}
+    {"arg":"string/number","description":"value"},
+    {"arg":"pattern","description":"pattern to compare value with, you can use '%' as a wildcard, '_' as a single char and '\\\\' to escape."}
   ],
   "examples": [
-	{ "expression":"'A' LIKE 'A'", "returns":"1"},
-	{ "expression":"'A' LIKE 'a'", "returns":"0"},
-	{ "expression":"'A' LIKE 'B'", "returns":"0"},
-	{ "expression":"'ABC' LIKE 'B'", "returns":"0"},
-	{ "expression":"'ABC' LIKE '%B%'", "returns":"1"}
+    { "expression":"'A' LIKE 'A'", "returns":"1"},
+    { "expression":"'A' LIKE 'a'", "returns":"0"},
+    { "expression":"'A' LIKE 'B'", "returns":"0"},
+    { "expression":"'ABC' LIKE 'B'", "returns":"0"},
+    { "expression":"'ABC' LIKE '_B_'", "returns":"1"},
+    { "expression":"'ABCD' LIKE '_B_'", "returns":"0"},
+    { "expression":"'ABCD' LIKE '_B%'", "returns":"1"},
+    { "expression":"'ABCD' LIKE '%B%'", "returns":"1"},
+    { "expression":"'1%' LIKE '1\\\\%'", "returns":"1"},
+    { "expression":"'1_' LIKE '1\\\\%'", "returns":"0"}
   ]
 }

src/core/qgsexpression.cpp

@@ -4343,9 +4343,33 @@ QVariant QgsExpression::NodeBinaryOperator::eval( QgsExpression *parent, const Q
         if ( mOp == boLike || mOp == boILike || mOp == boNotLike || mOp == boNotILike ) // change from LIKE syntax to regexp
         {
           QString esc_regexp = QRegExp::escape( regexp );
-          // XXX escape % and _  ???
-          esc_regexp.replace( '%', ".*" );
-          esc_regexp.replace( '_', '.' );
+          // manage escape % and _
+          if ( esc_regexp.startsWith( '%' ) )
+          {
+            esc_regexp.replace( 0, 1, ".*" );
+          }
+          QRegExp rx( "[^\\\\](%)" );
+          int pos = 0;
+          while (( pos = rx.indexIn( esc_regexp, pos ) ) != -1 )
+          {
+            esc_regexp.replace( pos + 1, 1, ".*" );
+            pos += 1;
+          }
+          rx.setPattern( "\\\\%" );
+          esc_regexp.replace( rx, "%" );
+          if ( esc_regexp.startsWith( '_' ) )
+          {
+            esc_regexp.replace( 0, 1, "." );
+          }
+          rx.setPattern( "[^\\\\](_)" );
+          pos = 0;
+          while (( pos = rx.indexIn( esc_regexp, pos ) ) != -1 )
+          {
+            esc_regexp.replace( pos + 1, 1, '.' );
+            pos += 1;
+          }
+          rx.setPattern( "\\\\_" );
+          esc_regexp.replace( rx, "_" );
           matches = QRegExp( esc_regexp, mOp == boLike || mOp == boNotLike ? Qt::CaseSensitive : Qt::CaseInsensitive ).exactMatch( str );
         }
         else

tests/src/core/testqgsexpression.cpp

@@ -482,9 +482,13 @@ class TestQgsExpression: public QObject
 
       // regexp, like
       QTest::newRow( "like 1" ) << "'hello' like '%ll_'" << false << QVariant( 1 );
-      QTest::newRow( "like 2" ) << "'hello' like 'lo'" << false << QVariant( 0 );
-      QTest::newRow( "like 3" ) << "'hello' like '%LO'" << false << QVariant( 0 );
+      QTest::newRow( "like 2" ) << "'hello' like '_el%'" << false << QVariant( 1 );
+      QTest::newRow( "like 3" ) << "'hello' like 'lo'" << false << QVariant( 0 );
+      QTest::newRow( "like 4" ) << "'hello' like '%LO'" << false << QVariant( 0 );
       QTest::newRow( "ilike" ) << "'hello' ilike '%LO'" << false << QVariant( 1 );
+      // the \\\\ is like \\ in the interface
+      QTest::newRow( "like escape 1" ) << "'1%' like '1\\\\%'" << false << QVariant( 1 );
+      QTest::newRow( "like escape 2" ) << "'1_' like '1\\\\%'" << false << QVariant( 0 );
       QTest::newRow( "regexp 1" ) << "'hello' ~ 'll'" << false << QVariant( 1 );
       QTest::newRow( "regexp 2" ) << "'hello' ~ '^ll'" << false << QVariant( 0 );
       QTest::newRow( "regexp 3" ) << "'hello' ~ 'llo$'" << false << QVariant( 1 );