From 955bd297b2038127a7e9c8d941430e790792e44c Mon Sep 17 00:00:00 2001
From: Andrew Gvozdev <angvoz.dev@gmail.com>
Date: Mon, 16 Apr 2012 14:41:19 -0400
Subject: [PATCH] Workaround for Java problem on Windows with releasing buffers
 for memory-mapped files java.io.FileNotFoundException:
 C:\workspace\junit-workspace\.metadata\.plugins\org.eclipse.cdt.core\language.settings.xml
 (The requested operation cannot be performed on a file with a user-mapped
 section open) 	at java.io.FileOutputStream.open(Native Method) 	at
 java.io.FileOutputStream.<init>(Unknown Source) 	at
 java.io.FileOutputStream.<init>(Unknown Source) 	at
 org.eclipse.cdt.internal.core.XmlUtil.getFileOutputStreamWorkaround(XmlUtil.java:315)
 	at
 org.eclipse.cdt.internal.core.XmlUtil.serializeXml(XmlUtil.java:290) 	at
 org.eclipse.cdt.internal.core.language.settings.providers.LanguageSettingsProvidersSerializer.serializeLanguageSettingsWorkspace(LanguageSettingsProvidersSerializer.java:539)
 	at
 org.eclipse.cdt.internal.core.language.settings.providers.LanguageSettingsProvidersSerializer$1.runInWorkspace(LanguageSettingsProvidersSerializer.java:577)
 	at
 org.eclipse.core.internal.resources.InternalWorkspaceJob.run(InternalWorkspaceJob.java:38)
 	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)

---
 .../eclipse/cdt/internal/core/XmlUtil.java    | 57 +++++++++++++++++--
 1 file changed, 51 insertions(+), 6 deletions(-)

diff --git a/core/org.eclipse.cdt.core/utils/org/eclipse/cdt/internal/core/XmlUtil.java b/core/org.eclipse.cdt.core/utils/org/eclipse/cdt/internal/core/XmlUtil.java
index f996e5e26c3..76ffb5efe70 100644
--- a/core/org.eclipse.cdt.core/utils/org/eclipse/cdt/internal/core/XmlUtil.java
+++ b/core/org.eclipse.cdt.core/utils/org/eclipse/cdt/internal/core/XmlUtil.java
@@ -13,6 +13,7 @@ package org.eclipse.cdt.internal.core;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -228,13 +229,16 @@ public class XmlUtil {
 			return null;
 		}
 
-		InputStream xmlStream;
 		try {
-			xmlStream = new FileInputStream(xmlFile);
+			InputStream xmlStream = new FileInputStream(xmlFile);
+			try {
+				return loadXml(xmlStream);
+			} finally {
+				xmlStream.close();
+			}
 		} catch (Exception e) {
 			throw new CoreException(CCorePlugin.createStatus(Messages.XmlUtil_InternalErrorLoading, e));
 		}
-		return loadXml(xmlStream);
 	}
 
 	/**
@@ -245,8 +249,16 @@ public class XmlUtil {
 	 * @throws CoreException if something goes wrong.
 	 */
 	public static Document loadXml(IFile xmlFile) throws CoreException {
-		InputStream xmlStream = xmlFile.getContents();
-		return loadXml(xmlStream);
+		try {
+			InputStream xmlStream = xmlFile.getContents();
+			try {
+				return loadXml(xmlStream);
+			} finally {
+				xmlStream.close();
+			}
+		} catch (Exception e) {
+			throw new CoreException(CCorePlugin.createStatus(Messages.XmlUtil_InternalErrorLoading, e));
+		}
 	}
 
 	/**
@@ -273,13 +285,46 @@ public class XmlUtil {
 
 		XmlUtil.prettyFormat(doc);
 		DOMSource source = new DOMSource(doc);
-		StreamResult result = new StreamResult(new FileOutputStream(storeFile));
+		StreamResult result = new StreamResult(getFileOutputStreamWorkaround(storeFile));
 		transformer.transform(source, result);
 
 		result.getOutputStream().close();
 		ResourcesUtil.refreshWorkspaceFiles(uriLocation);
 	}
 
+	/**
+	 * Workaround for Java problem on Windows with releasing buffers for memory-mapped files.
+	 *
+	 * @see "http://stackoverflow.com/questions/3602783/file-access-synchronized-on-java-object"
+	 * @see "http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6354433"
+	 * @see "http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4715154"
+	 * @see "http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4469299"
+	 */
+	private static FileOutputStream getFileOutputStreamWorkaround(java.io.File storeFile) throws FileNotFoundException {
+		final int maxCount = 10;
+		for (int i = 0; i <= maxCount; i++) {
+			try {
+				// there is no sleep on first round
+				Thread.sleep(10 * i);
+			} catch (InterruptedException e) {
+				// restore interrupted status
+				Thread.currentThread().interrupt();
+			}
+			try {
+				return new FileOutputStream(storeFile);
+			} catch (FileNotFoundException e) {
+				// only apply workaround for the very specific exception
+				if (i >= maxCount || !e.getMessage().contains("The requested operation cannot be performed on a file with a user-mapped section open")) { //$NON-NLS-1$
+					throw e;
+				}
+//				CCorePlugin.log(new Status(IStatus.INFO, CCorePlugin.PLUGIN_ID, "Workaround for concurrent access to memory-mapped files applied, attempt " + (i + 1), e)); //$NON-NLS-1$
+			}
+		}
+
+		// will never get here
+		return null;
+	}
+
 	/**
 	 * Serialize XML Document into a byte array.
 	 * @param doc - DOM Document to serialize.