Add method for designer

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/Node.java

@@ -121,6 +121,23 @@ public interface Node extends Reportable {
     @Override
     FileLocation getReportLocation();
 
+    /**
+     * Returns a region of text delimiting the node in the underlying
+     * text document. This does not necessarily match the
+     * {@link #getReportLocation() report location}.
+     *
+     * @implNote The default implementation uses the {@link #getReportLocation()}
+     *     to create a region.
+     */
+    default TextRegion getTextRegion() {
+        @SuppressWarnings("PMD.CloseResource")
+        TextDocument document = getAstInfo().getTextDocument();
+        FileLocation loc = getReportLocation();
+        int startOffset = document.offsetAtLineColumn(loc.getStartLine(), loc.getStartColumn());
+        int endOffset = document.offsetAtLineColumn(loc.getEndLine(), loc.getEndColumn());
+        return TextRegion.fromBothOffsets(startOffset, endOffset);
+    }
+
 
     // Those are kept here because they're handled specially as XPath
     // attributes

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/TextAvailableNode.java

@@ -20,8 +20,11 @@ public interface TextAvailableNode extends Node {
      * Returns the exact region of text delimiting
      * the node in the underlying text document. Note
      * that {@link #getReportLocation()} does not need
-     * to match this region.
+     * to match this region. {@link #getReportLocation()}
+     * can be scoped down to a specific token, eg the
+     * class identifier.
      */
+    @Override
     TextRegion getTextRegion();
 
     /**

pmd-core/src/main/java/net/sourceforge/pmd/lang/document/FileLocation.java

@@ -77,8 +77,18 @@ public final class FileLocation {
         return fileName;
     }
 
+    /**
+     * Inclusive, 1-based line number.
+     *
+     * @deprecated Use {@link #getStartLine()}.
+     */
+    @Deprecated
+    public int getBeginLine() { // todo rename to getStartLine
+        return getStartLine();
+    }
+
     /** Inclusive, 1-based line number. */
-    public int getBeginLine() {
+    public int getStartLine() {
         return beginLine;
     }
 
@@ -87,8 +97,18 @@ public final class FileLocation {
         return endLine;
     }
 
+    /**
+     * Inclusive, 1-based column number.
+     *
+     * @deprecated Use {@link #getStartColumn()}.
+     */
+    @Deprecated
+    public int getBeginColumn() { // todo rename to getStartLine
+        return getStartColumn();
+    }
+
     /** Inclusive, 1-based column number. */
-    public int getBeginColumn() {
+    public int getStartColumn() {
         return beginColumn;
     }
 

pmd-core/src/main/java/net/sourceforge/pmd/lang/document/RootTextDocument.java

@@ -83,6 +83,12 @@ final class RootTextDocument extends BaseCloseable implements TextDocument {
         );
     }
 
+    @Override
+    public int offsetAtLineColumn(int line, int column) {
+        SourceCodePositioner positioner = content.getPositioner();
+        return positioner.offsetFromLineColumn(line, column);
+    }
+
     @Override
     public TextRegion createLineRange(int startLineInclusive, int endLineInclusive) {
         SourceCodePositioner positioner = content.getPositioner();

pmd-core/src/main/java/net/sourceforge/pmd/lang/document/TextDocument.java

@@ -111,7 +111,9 @@ public interface TextDocument extends Closeable {
 
 
     /**
-     * Turn a text region into a {@link FileLocation}.
+     * Turn a text region into a {@link FileLocation}. This computes
+     * the line/column information for both start and end offset of
+     * the region.
      *
      * @return A new file position
      *
@@ -119,8 +121,15 @@ public interface TextDocument extends Closeable {
      */
     FileLocation toLocation(TextRegion region);
 
-
-    // todo doc
+    /**
+     * Create a location from its positions as lines/columns. The file
+     * name is the display name of this document.
+     *
+     * @param bline Start line
+     * @param bcol  Start column
+     * @param eline End line
+     * @param ecol  End column
+     */
     default FileLocation createLocation(int bline, int bcol, int eline, int ecol) {
         return FileLocation.location(getDisplayName(), bline, bcol, eline, ecol);
     }
@@ -136,6 +145,17 @@ public interface TextDocument extends Closeable {
         return toLocation(TextRegion.fromOffsetLength(offset, 0)).getBeginLine();
     }
 
+    /**
+     * Returns the offset at the given line and column number. This is
+     * the dual of
+     *
+     * @param line   Line number (1-based)
+     * @param column Column number (1-based)
+     *
+     * @return an offset (0-based)
+     */
+    int offsetAtLineColumn(int line, int column);
+
     /**
      * Closing a document closes the underlying {@link TextFile}.
      * New editors cannot be produced after that, and the document otherwise

pmd-core/src/main/java/net/sourceforge/pmd/lang/document/TextRegion.java

@@ -194,6 +194,17 @@ public final class TextRegion implements Comparable<TextRegion> {
         return new TextRegion(startOffset, endOffset - startOffset);
     }
 
+    /**
+     * Builds a new region with zero length and placed at the given offset.
+     *
+     * @param startOffset Offset for start and end of the position.
+     *
+     * @throws AssertionError If the offset is negative
+     */
+    public static TextRegion caretAt(int startOffset) {
+        return new TextRegion(startOffset, 0);
+    }
+
     /**
      * Checks that the parameters are a valid region, this is provided
      * to debug, will be a noop unless assertions are enabled.

pmd-core/src/test/java/net/sourceforge/pmd/lang/document/TextDocumentTest.java

@@ -140,6 +140,26 @@ public class TextDocumentTest {
         assertEquals(1 + "bonjour".length(), withLines.getEndColumn());
     }
 
+    @Test
+    public void testOffsetFromLineColumn() {
+        TextDocument doc = TextDocument.readOnlyString("bonjour\noa\n", dummyVersion);
+
+        assertEquals(0, doc.offsetAtLineColumn(1, 1));
+        assertEquals(1, doc.offsetAtLineColumn(1, 2));
+        assertEquals(2, doc.offsetAtLineColumn(1, 3));
+        assertEquals(3, doc.offsetAtLineColumn(1, 4));
+        assertEquals(4, doc.offsetAtLineColumn(1, 5));
+        assertEquals(5, doc.offsetAtLineColumn(1, 6));
+        assertEquals(6, doc.offsetAtLineColumn(1, 7));
+        assertEquals(7, doc.offsetAtLineColumn(1, 8));
+        assertEquals(8, doc.offsetAtLineColumn(1, 9));
+        assertEquals(8, doc.offsetAtLineColumn(2, 1));
+        assertEquals(9, doc.offsetAtLineColumn(2, 2));
+        assertEquals(10, doc.offsetAtLineColumn(2, 3));
+        assertEquals(11, doc.offsetAtLineColumn(2, 4));
+        assertEquals(11, doc.offsetAtLineColumn(3, 1));
+    }
+
     @Test
     public void testLineRange() {
         TextDocument doc = TextDocument.readOnlyString("bonjour\noha\ntristesse", dummyVersion);

pmd-javascript/src/main/java/net/sourceforge/pmd/lang/ecmascript/ast/AbstractEcmascriptNode.java

@@ -39,7 +39,8 @@ abstract class AbstractEcmascriptNode<T extends AstNode> extends AbstractNode<Ab
         return getTextDocument().toLocation(getTextRegion());
     }
 
-    private TextRegion getTextRegion() {
+    @Override
+    public TextRegion getTextRegion() {
         return TextRegion.fromOffsetLength(node.getAbsolutePosition(), node.getLength());
     }