Fix handling of godef result, use correct source truth.

plugin_tooling/src/com/googlecode/goclipse/tooling/oracle/GoOperationContext.java

@@ -45,6 +45,10 @@ public ISourceBuffer getSourceBuffer() {
 		return sourceBuffer;
 	}
 
+	public SourceOpContext getOpContext() {
+		return opContext;
+	}
+
 	public IToolOperationService getToolOpService() {
 		return toolOpService;
 	}

plugin_tooling/src/com/googlecode/goclipse/tooling/tools/GoFindDefinitionOperation.java

@@ -34,6 +34,10 @@ public GoFindDefinitionOperation(GoOperationContext goOpContext) {
 		this.goOpContext = assertNotNull(goOpContext);
 	}
 
+	public GoOperationContext getGoOpContext() {
+		return goOpContext;
+	}
+
 	public SourceLocation getValidResult(IOperationMonitor om) 
 			throws CommonException, OperationCancellation, OperationSoftFailure {
 

plugin_tooling/src/com/googlecode/goclipse/tooling/tools/GoFindDocOperation.java

@@ -12,21 +12,15 @@
 
 import static melnorme.utilbox.core.Assert.AssertNamespace.assertNotNull;
 
-import java.io.IOException;
-
 import com.googlecode.goclipse.tooling.oracle.GoDocParser;
 
-import melnorme.lang.tooling.common.SourceLineColumnRange;
 import melnorme.lang.tooling.common.ops.IOperationMonitor;
-import melnorme.lang.tooling.parser.SourceLinesInfo;
 import melnorme.lang.tooling.toolchain.ops.AbstractToolOperation;
 import melnorme.lang.tooling.toolchain.ops.OperationSoftFailure;
 import melnorme.lang.tooling.toolchain.ops.SourceLocation;
+import melnorme.lang.tooling.toolchain.ops.SourceOpContext;
 import melnorme.utilbox.concurrency.OperationCancellation;
 import melnorme.utilbox.core.CommonException;
-import melnorme.utilbox.misc.FileUtil;
-import melnorme.utilbox.misc.Location;
-import melnorme.utilbox.misc.StringUtil;
 
 public class GoFindDocOperation implements AbstractToolOperation<String> {
 
@@ -46,23 +40,11 @@ public String executeToolOperation(IOperationMonitor om) throws CommonException,
 			return null; // No documentation will be available
 		}
 
-		/* FIXME: review this code */
-		String fileContents = readFileContents(findDefResult.getFileLocation());
-		SourceLinesInfo linesInfo = new SourceLinesInfo(fileContents);
-
-		SourceLineColumnRange sourceLCRange = findDefResult.getSourceRange();
-		int offset = linesInfo.getOffsetForLine(sourceLCRange.getValidLineIndex()) + sourceLCRange.getValidColumnIndex();
+		SourceOpContext opContext = findDefOp.getGoOpContext().getOpContext();
+		String fileContents = opContext.getSourceFor(findDefResult.getFileLocation());
+		int offset = opContext.getOffsetFor(findDefResult);
 
 		return new GoDocParser().parseDocForDefinitionAt(fileContents, offset);
 	}
-
-	public static String readFileContents(Location location) throws CommonException {
-		try {
-			// TODO: we might need to do auto-detect of encoding.
-			return FileUtil.readStringFromFile(location.toPath(), StringUtil.UTF8);
-		} catch(IOException e) {
-			throw new CommonException(e.getMessage(), e.getCause());
-		}
-	}
 
 }