Bug 509186 - Require an exact match for help proposals when providing context information

Change-Id: I06ccd65a0304921ebf2adbd556a89c8685237a8a

core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/chelp/CHelpProviderTester.java

@@ -59,10 +59,15 @@ public class CHelpProviderTester {
 	private class CHelpBook implements ICHelpBook {
 		private int fCHelpType;
 		private String fTitle;
+		private List<IFunctionSummary> fFunctions = new ArrayList<>();
 
 		public CHelpBook(String providerID, int type) {
 			fCHelpType = type;
 			fTitle = generateBookTitle(providerID, type);
+			if (fCHelpType == HELP_TYPE_C) {
+				fFunctions.add(new FunctionSummary(this, "setvbuf", providerID));
+				fFunctions.add(new FunctionSummary(this, "wait", providerID));
+			}
 		}
 
 		@Override
@@ -74,6 +79,16 @@ public class CHelpProviderTester {
 		public int getCHelpType() {
 			return fCHelpType;
 		}
+
+		public List<IFunctionSummary> getMatchingFunctions(String prefix) {
+			List<IFunctionSummary> result = new ArrayList<>();
+			for (IFunctionSummary function : fFunctions) {
+				if (function.getName().startsWith(prefix)) {
+					result.add(function);
+				}
+			}
+			return result;
+		}
 	}
 
 	private class CHelpResourceDescriptor implements ICHelpResourceDescriptor {
@@ -272,11 +287,13 @@ public class CHelpProviderTester {
 	}
 
 	public IFunctionSummary[] generateMatchingFunctions(ICHelpBook[] helpBooks, String prefix, String providerID) {
-		IFunctionSummary sum[] = new IFunctionSummary[helpBooks.length];
-		for (int i = 0; i < helpBooks.length; i++) {
-			sum[i] = new FunctionSummary(helpBooks[i], prefix, providerID);
+		ArrayList<IFunctionSummary> lst = new ArrayList<IFunctionSummary>();
+		for (ICHelpBook helpBook : helpBooks) {
+			if (helpBook instanceof CHelpBook) {
+				lst.addAll(((CHelpBook) helpBook).getMatchingFunctions(prefix));
 			}
-		return sum;
+		}
+		return lst.toArray(new IFunctionSummary[lst.size()]);
 	}
 
 	public ICHelpBook[] generateCHelpBooks(final String providerID) {

core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/contentassist2/HelpProposalTests.java

@@ -7,6 +7,8 @@
  *******************************************************************************/
 package org.eclipse.cdt.ui.tests.text.contentassist2;
 
+import static org.eclipse.cdt.ui.tests.text.contentassist2.AbstractContentAssistTest.CompareType.ID;
+
 import org.eclipse.cdt.core.testplugin.util.BaseTestCase;
 import org.eclipse.cdt.ui.tests.chelp.CHelpTestInfoProvider;
 
@@ -41,6 +43,10 @@ public class HelpProposalTests extends CompletionTestBase {
 		super.tearDown();
 	}
 	
+	// Note: The help proposal completions for C library functions that are proposed
+	//       in this test are defined in the CHelpProposalTester.CHelpBook constructor.
+	//       When writing a new test case, add any necessary new functions there.
+	
 	//	int main() {
 	//	    setvbuf(file, NULL, _IOLBF, /*cursor*/);
 	//	}
@@ -53,4 +59,15 @@ public class HelpProposalTests extends CompletionTestBase {
 		assertEquals("", proposal.getReplacementString());
 		assertNotNull(proposal.getContextInformation());
 	}
+	
+	//	struct Waldo {
+	//		Waldo(int, int);
+	//	};
+	//	int main() {
+	//		Waldo w(/*cursor*/
+	//	}
+	public void testHelpProposalInInappropriateContext_509186() throws Exception {
+		String[] expected = new String[] { "Waldo(const Waldo &)", "Waldo(int, int)" };
+		assertCompletionResults(fCursorOffset, expected, ID);
+	}
 }

core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/contentassist/HelpCompletionProposalComputer.java

@@ -102,9 +102,21 @@ public class HelpCompletionProposalComputer extends ParsingBasedProposalComputer
 		Image image = CUIPlugin.getImageDescriptorRegistry().get(
 				CElementImageProvider.getFunctionImageDescriptor());
 
+		// If we are only providing context information, "prefix" is a complete
+		// function name, and we only want functions matching it exactly as
+		// proposals.
+		// TODO: It would be more efficient to expose this flag in
+		//       IContentAssistHelpInvocationContext and have the help providers
+		//       not generate prefix matches to begin with if it's set.
+		boolean requireExactMatch = cContext.isContextInformationStyle();
+
 		List<ICompletionProposal> proposals = new ArrayList<ICompletionProposal>();
 
 		for (IFunctionSummary summary : summaries) {
+			if (requireExactMatch && !summary.getName().equals(prefix)) {
+				continue;
+			}
+			
 			String fname = summary.getName() + "()"; //$NON-NLS-1$
 			String fdesc = summary.getDescription();
 			IFunctionSummary.IFunctionPrototypeSummary fproto = summary