From ec3283c69dbf1d1c118524946095d96fbb230b9f Mon Sep 17 00:00:00 2001
From: Markus Schorn <markus.schorn@windriver.com>
Date: Mon, 21 Jan 2008 13:24:27 +0000
Subject: [PATCH] Caches a step computed by the macro expansion explorer, bug
 23540.

---
 .../core/parser/scanner/MultiMacroExpansionExplorer.java | 9 ++++++++-
 .../internal/ui/text/c/hover/CMacroExpansionInput.java   | 4 +++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/scanner/MultiMacroExpansionExplorer.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/scanner/MultiMacroExpansionExplorer.java
index 05264b33c24..b34bd9ab332 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/scanner/MultiMacroExpansionExplorer.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/scanner/MultiMacroExpansionExplorer.java
@@ -57,6 +57,8 @@ public class MultiMacroExpansionExplorer extends MacroExpansionExplorer {
 	private final SingleMacroExpansionExplorer[] fDelegates;
 	private final String fFilePath;
 	private final Map<IMacroBinding, IASTFileLocation> fMacroLocations;
+	private MacroExpansionStep fCachedStep;
+	private int fCachedStepID= -1;
 
 	public MultiMacroExpansionExplorer(IASTTranslationUnit tu, IASTFileLocation loc) {
 		if (tu == null || loc == null || loc.getNodeLength() == 0) {
@@ -191,6 +193,9 @@ public class MultiMacroExpansionExplorer extends MacroExpansionExplorer {
 		if (step < 0) {
 			throw new IndexOutOfBoundsException();
 		}
+		if (fCachedStep != null && fCachedStepID == step) {
+			return fCachedStep;
+		}
 		int i;
 		MacroExpansionStep dresult= null;
 		StringBuilder before= new StringBuilder();
@@ -218,7 +223,9 @@ public class MultiMacroExpansionExplorer extends MacroExpansionExplorer {
 		
 		List<ReplaceEdit> replacements= new ArrayList<ReplaceEdit>();
 		shiftAndAddEdits(shift, dresult.getReplacements(), replacements);
-		return new MacroExpansionStep(before.toString(), dresult.getExpandedMacro(), dresult.getLocationOfExpandedMacroDefinition(), replacements.toArray(new ReplaceEdit[replacements.size()]));
+		fCachedStep= new MacroExpansionStep(before.toString(), dresult.getExpandedMacro(), dresult.getLocationOfExpandedMacroDefinition(), replacements.toArray(new ReplaceEdit[replacements.size()]));
+		fCachedStepID= step;
+		return fCachedStep;
 	}
 	
 	private void appendGap(StringBuilder result, int i) {
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/c/hover/CMacroExpansionInput.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/c/hover/CMacroExpansionInput.java
index 92712588fa2..52efaee65d4 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/c/hover/CMacroExpansionInput.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/c/hover/CMacroExpansionInput.java
@@ -156,7 +156,9 @@ public class CMacroExpansionInput {
 				if (node instanceof IASTName) {
 					IASTName macroName= (IASTName) node;
 					IBinding binding= macroName.getBinding();
-					if (binding instanceof IMacroBinding && !macroName.isDefinition()) {
+					// skip macro references that belong to a macro definition or an undef directive
+					if (binding instanceof IMacroBinding && !macroName.isDefinition() &&
+							macroName.getParent() instanceof IASTTranslationUnit) {
 						addExpansionNode(node);
 						createMacroExpansionExplorer(ast);
 						return Status.OK_STATUS;