Added file size to the condition used for determining if the file

has changed since it was indexed. Timestamps on Unix have 1-sec
granularity and comparison based on them alone may produce false
negatives.

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/index/IIndexFragmentFile.java

@@ -34,10 +34,16 @@ public interface IIndexFragmentFile extends IIndexFile {
 	void setContentsHash(long hash) throws CoreException;
 
 	/**
-	 * Sets the hash-code of the file encoding.
+	 * Returns the hash-code computed by combining the file size and the file encoding.
+	 * @return hashcode a hash-code or <code>0</code> if it is unknown.
+	 */
+	int getSizeAndEncodingHashcode() throws CoreException;
+
+	/**
+	 * Sets the hash-code computed by combining the file size and the file encoding.
 	 * @param hashcode a hash-code or <code>0</code> if it is unknown.
 	 */
-	void setEncodingHashcode(int hashcode) throws CoreException;
+	void setSizeAndEncodingHashcode(int hashcode) throws CoreException;
 
 	/**
 	 * Sets the flag that determines whether the file is a header with #pragma once statement

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/indexer/StandaloneIndexerInputAdapter.java

@@ -8,6 +8,7 @@
  * Contributors:
  *     Markus Schorn - initial API and implementation
  *     IBM Corporation
+ *     Sergey Prigogin (Google)
  *******************************************************************************/ 
 package org.eclipse.cdt.internal.core.indexer;
 
@@ -55,6 +56,11 @@ public class StandaloneIndexerInputAdapter extends IndexerInputAdapter {
 		return new File(URIUtil.toPath(location.getURI()).toOSString()).lastModified();
 	}
 
+	@Override
+	public long getFileSize(IIndexFileLocation location) {
+		return new File(URIUtil.toPath(location.getURI()).toOSString()).length();
+	}
+
 	@Override
 	public String getEncoding(IIndexFileLocation ifl) {
 		String encoding= getFileEncoding(getASTPath(ifl));

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/AbstractIndexerTask.java

@@ -71,12 +71,11 @@ import org.eclipse.osgi.util.NLS;
  * @since 5.0
  */
 public abstract class AbstractIndexerTask extends PDOMWriter {
-	public static enum UnusedHeaderStrategy {
+	public static enum UnusedHeaderStrategy { skip, useC, useCPP, useDefaultLanguage, useBoth }
-		skip, useC, useCPP, useDefaultLanguage, useBoth
-	}
 	private static final int MAX_ERRORS = 500;
 
-	private static enum UpdateKind {REQUIRED_SOURCE, REQUIRED_HEADER, ONE_LINKAGE_HEADER, OTHER_HEADER}
+	private static enum UpdateKind { REQUIRED_SOURCE, REQUIRED_HEADER, ONE_LINKAGE_HEADER, OTHER_HEADER }
+
 	private static class LinkageTask {
 		final int fLinkageID;
 		private final Map<IIndexFileLocation, LocationTask> fLocationTasks;
@@ -687,7 +686,7 @@ public abstract class AbstractIndexerTask extends PDOMWriter {
 			Object tu, IIndexFragmentFile file)	throws CoreException {
 		if (checkTimestamps) {
 			if (fResolver.getLastModified(ifl) != file.getTimestamp() || 
-					fResolver.getEncoding(ifl).hashCode() != file.getEncodingHashcode()) {
+					computeFileSizeAndEncodingHashcode(ifl) != file.getSizeAndEncodingHashcode()) {
 				if (checkFileContentsHash && computeFileContentsHash(tu) == file.getContentsHash()) {
 					return false;
 				}

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/IndexerInputAdapter.java

@@ -7,6 +7,7 @@
  *
  * Contributors:
  *     Markus Schorn - initial API and implementation
+ *     Sergey Prigogin (Google)
  *******************************************************************************/ 
 package org.eclipse.cdt.internal.core.pdom;
 
@@ -22,7 +23,6 @@ import org.eclipse.cdt.core.parser.IScannerInfo;
  * @since 5.0
  */
 public abstract class IndexerInputAdapter extends ASTFilePathResolver {
-
 	/**
 	 * Returns an object representing an input file for the given index location,
 	 * or <code>null</code>, if it does not exist.
@@ -34,6 +34,16 @@ public abstract class IndexerInputAdapter extends ASTFilePathResolver {
 	 */
 	public abstract long getLastModified(IIndexFileLocation location);
 
+	/**
+	 * Returns the size of the file in bytes, or 0 if the file does not exist.
+	 */
+	public abstract long getFileSize(IIndexFileLocation ifl);
+
+	/**
+	 * Returns the encoding for the file.
+	 */
+	public abstract String getEncoding(IIndexFileLocation ifl);
+
 	/**
 	 * Create an index location for the given input file.
 	 */
@@ -82,9 +92,4 @@ public abstract class IndexerInputAdapter extends ASTFilePathResolver {
 	 * Returns a code reader for the given input file.
 	 */
 	public abstract FileContent getCodeReader(Object tu);
-
-	/**
-	 * Returns the encoding for the file.
-	 */
-	public abstract String getEncoding(IIndexFileLocation ifl);
 }

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/PDOM.java

@@ -213,10 +213,11 @@ public class PDOM extends PlatformObject implements IPDOM {
 	 *  120.1 - Specializations of using declarations, bug 357293.
 	 *  121.0 - Multiple variants of included header file, bug 197989.
 	 *  122.0 - Compacting strings
+	 *  123.0 - Combined file size and encoding hash code.
 	 */
-	private static final int MIN_SUPPORTED_VERSION= version(122, 0);
+	private static final int MIN_SUPPORTED_VERSION= version(123, 0);
-	private static final int MAX_SUPPORTED_VERSION= version(122, Short.MAX_VALUE);
+	private static final int MAX_SUPPORTED_VERSION= version(123, Short.MAX_VALUE);
-	private static final int DEFAULT_VERSION = version(122, 0);
+	private static final int DEFAULT_VERSION = version(123, 0);
 
 	private static int version(int major, int minor) {
 		return (major << 16) + minor;
@@ -232,12 +233,15 @@ public class PDOM extends PlatformObject implements IPDOM {
 	public static boolean isSupportedVersion(int vers) {
 		return vers >= MIN_SUPPORTED_VERSION && vers <= MAX_SUPPORTED_VERSION;
 	}
+
 	public static int getMinSupportedVersion() {
 		return MIN_SUPPORTED_VERSION;
 	}
+
 	public static int getMaxSupportedVersion() {
 		return MAX_SUPPORTED_VERSION;
 	}
+
 	public static String versionString(int version) {
 		final int major= version >> 16;
 		final int minor= version & 0xffff;

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/PDOMWriter.java

@@ -560,7 +560,7 @@ abstract public class PDOMWriter {
 				index.setFileContent(file, linkageID, includeInfoArray, macros, names, fResolver, lock);
 			}
 			file.setTimestamp(fResolver.getLastModified(location));
-			file.setEncodingHashcode(fResolver.getEncoding(location).hashCode());
+			file.setSizeAndEncodingHashcode(computeFileSizeAndEncodingHashcode(location));
 			file.setContentsHash(astFile.fContentsHash);
 			file = index.commitUncommittedFile();
 		} finally {
@@ -569,6 +569,10 @@ abstract public class PDOMWriter {
 		return file;
 	}
 
+	protected int computeFileSizeAndEncodingHashcode(IIndexFileLocation location) {
+		return ((int) fResolver.getFileSize(location)) + 31 * fResolver.getEncoding(location).hashCode();
+	}
+
 	private boolean isContextFor(IIndexFragmentFile oldFile, IASTPreprocessorIncludeStatement stmt)
 			throws CoreException {
 		IIndexFile target= stmt.getImportedIndexFile();

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/db/IBTreeVisitor.java

@@ -19,7 +19,6 @@ import org.eclipse.core.runtime.CoreException;
  * The visitor visits all records where compare returns 0. 
  */
 public interface IBTreeVisitor {
-
 	/**
 	 * Compare the record against an internally held key. The comparison must be
 	 * compatible with the one used for the btree.
@@ -38,5 +37,4 @@ public interface IBTreeVisitor {
 	 * @throws CoreException
 	 */
 	public abstract boolean visit(long record) throws CoreException;	
-	
 }

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/dom/PDOMFile.java

@@ -74,8 +74,8 @@ public class PDOMFile implements IIndexFragmentFile {
 	private static final int FLAGS= LINKAGE_ID + 3;  // size 1
 	private static final int TIME_STAMP = FLAGS + 1; // long
 	private static final int CONTENT_HASH= TIME_STAMP + 8;  // long
-	private static final int ENCODING_HASH= CONTENT_HASH + 8;
+	private static final int SIZE_AND_ENCODING_HASH= CONTENT_HASH + 8;
-	private static final int LAST_USING_DIRECTIVE= ENCODING_HASH + 4;
+	private static final int LAST_USING_DIRECTIVE= SIZE_AND_ENCODING_HASH + 4;
 	private static final int FIRST_MACRO_REFERENCE= LAST_USING_DIRECTIVE + Database.PTR_SIZE;
 	private static final int SIGNIFICANT_MACROS= FIRST_MACRO_REFERENCE + Database.PTR_SIZE;
 	private static final int RECORD_SIZE= SIGNIFICANT_MACROS + Database.PTR_SIZE;   // 8*PTR_SIZE + 3+1+8+8+4 = 56
@@ -205,7 +205,7 @@ public class PDOMFile implements IIndexFragmentFile {
 		}
 
 		setTimestamp(sourceFile.getTimestamp());
-		setEncodingHashcode(sourceFile.getEncodingHashcode());
+		setSizeAndEncodingHashcode(sourceFile.getSizeAndEncodingHashcode());
 		setContentsHash(sourceFile.getContentsHash());
 
 		// Transfer the flags. 
@@ -327,15 +327,21 @@ public class PDOMFile implements IIndexFragmentFile {
 	}
 
 	@Override
-	public int getEncodingHashcode() throws CoreException {
+	public int getSizeAndEncodingHashcode() throws CoreException {
 		Database db = fLinkage.getDB();
-		return db.getInt(record + ENCODING_HASH);
+		return db.getInt(record + SIZE_AND_ENCODING_HASH);
 	}
 
 	@Override
-	public void setEncodingHashcode(int hashcode) throws CoreException {
+	@Deprecated
+	public int getEncodingHashcode() throws CoreException {
+		return 0;
+	}
+
+	@Override
+	public void setSizeAndEncodingHashcode(int hashcode) throws CoreException {
 		Database db= fLinkage.getDB();
-		db.putInt(record + ENCODING_HASH, hashcode);
+		db.putInt(record + SIZE_AND_ENCODING_HASH, hashcode);
 	}
 
 	@Override

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/ProjectIndexerInputAdapter.java

@@ -178,6 +178,24 @@ public class ProjectIndexerInputAdapter extends IndexerInputAdapter {
 		return 0;
 	}
 
+	@Override
+	public long getFileSize(IIndexFileLocation ifl) {
+		String fullPath= ifl.getFullPath();
+		IPath location= null;
+		if (fullPath != null) {
+			IResource res= ResourcesPlugin.getWorkspace().getRoot().findMember(new Path(fullPath));
+			if (res != null) {
+				location = res.getLocation();
+			}
+		} else {
+			location= IndexLocationFactory.getAbsolutePath(ifl);
+		}
+		if (location != null) {
+			return location.toFile().length();
+		}
+		return 0;
+	}
+
 	@Override
 	public String getEncoding(IIndexFileLocation ifl) {
 		String fullPath= ifl.getFullPath();