Bug 292062 - Provide a way to dynamically introspect an SWT port info

5 files changed, 143 insertions, 7 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/cocoa/org/eclipse/swt/internal/Platform.java b/bundles/org.eclipse.swt/Eclipse SWT PI/cocoa/org/eclipse/swt/internal/Platform.java
index ef6bfb1040..d0d35b454e 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/cocoa/org/eclipse/swt/internal/Platform.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/cocoa/org/eclipse/swt/internal/Platform.java
@@ -10,8 +10,48 @@
  *******************************************************************************/
 package org.eclipse.swt.internal;
 
+import java.io.*;
+import java.net.*;
+import java.util.jar.*;
+
 public class Platform {
 	
 public static final String PLATFORM = "cocoa"; //$NON-NLS-1$
 public static final Lock lock = new Lock ();
+
+public static boolean IsLoadable () {
+	URL url = Platform.class.getClassLoader ().getResource ("org/eclipse/swt/SWT.class"); //$NON-NLS-1$
+	if (!url.getProtocol ().equals ("jar")) { //$NON-NLS-1$
+		/* SWT is presumably running in a development environment */
+		return true;
+	}
+
+	try {
+		url = new URL (url.getPath ());
+	} catch (MalformedURLException e) {
+		/* should never happen since url's initial path value must be valid */
+	}
+	String path = url.getPath ();
+	int index = path.indexOf ('!');
+	File file = new File (path.substring (0, index));
+
+	try {
+		JarFile jar = new JarFile (file);
+		Manifest manifest = jar.getManifest ();
+		Attributes attributes = manifest.getMainAttributes ();
+
+		/*
+		* Cocoa has a special case since SWT's 32-bit library contains natives for both the
+		* x86 and PPC architectures.
+		*/
+		if (!Library.os ().equals (attributes.getValue ("SWT-OS"))) return false; //$NON-NLS-1$
+		String libraryArch = Library.arch ();
+		String manifestArch = attributes.getValue ("SWT-Arch"); //$NON-NLS-1$
+		return libraryArch.equals (manifestArch) || (manifestArch.equals ("x86") && libraryArch.equals ("ppc")); //$NON-NLS-1$ //$NON-NLS-2$ 
+	} catch (IOException e) {
+		/* should never happen for a valid SWT jar with the expected manifest values */
+	}
+
+	return false;	
+}
 }
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/org/eclipse/swt/internal/Platform.java b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/org/eclipse/swt/internal/Platform.java
index 7881f7080a..a334894c5c 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/org/eclipse/swt/internal/Platform.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/org/eclipse/swt/internal/Platform.java
@@ -14,7 +14,41 @@
  *******************************************************************************/
 package org.eclipse.swt.internal;
 
+import java.io.*;
+import java.net.*;
+import java.util.jar.*;
+
 public class Platform {
 	public static final String PLATFORM = "gtk"; //$NON-NLS-1$
 	public static final Lock lock = new Lock();
+
+public static boolean IsLoadable () {
+	URL url = Platform.class.getClassLoader ().getResource ("org/eclipse/swt/SWT.class"); //$NON-NLS-1$
+	if (!url.getProtocol ().equals ("jar")) { //$NON-NLS-1$
+		/* SWT is presumably running in a development environment */
+		return true;
+	}
+
+	try {
+		url = new URL (url.getPath ());
+	} catch (MalformedURLException e) {
+		/* should never happen since url's initial path value must be valid */
+	}
+	String path = url.getPath ();
+	int index = path.indexOf ('!');
+	File file = new File (path.substring (0, index));
+
+	try {
+		JarFile jar = new JarFile (file);
+		Manifest manifest = jar.getManifest ();
+		Attributes attributes = manifest.getMainAttributes ();
+		return Library.arch ().equals (attributes.getValue ("SWT-Arch")) && //$NON-NLS-1$
+				Library.os ().equals (attributes.getValue ("SWT-OS")); //$NON-NLS-1$
+	} catch (IOException e) {
+		/* should never happen for a valid SWT jar with the expected manifest values */
+	}
+
+	return false;	
+}
+
 }
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/win32/org/eclipse/swt/internal/Platform.java b/bundles/org.eclipse.swt/Eclipse SWT PI/win32/org/eclipse/swt/internal/Platform.java
index 9fae8d8b3b..39cb197c22 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/win32/org/eclipse/swt/internal/Platform.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/win32/org/eclipse/swt/internal/Platform.java
@@ -10,8 +10,42 @@
  *******************************************************************************/
 package org.eclipse.swt.internal;
 
+import java.io.*;
+import java.net.*;
+import java.util.jar.*;
+
 public class Platform {
-	
-public static final String PLATFORM = "win32"; //$NON-NLS-1$
-public static final Lock lock = new Lock ();
+
+	public static final String PLATFORM = "win32"; //$NON-NLS-1$
+	public static final Lock lock = new Lock ();
+
+public static boolean IsLoadable () {
+	URL url = Platform.class.getClassLoader ().getResource ("org/eclipse/swt/SWT.class"); //$NON-NLS-1$
+	if (!url.getProtocol ().equals ("jar")) { //$NON-NLS-1$
+		/* SWT is presumably running in a development environment */
+		return true;
+	}
+
+	try {
+		url = new URL (url.getPath ());
+	} catch (MalformedURLException e) {
+		/* should never happen since url's initial path value must be valid */
+	}
+	String path = url.getPath ();
+	int index = path.indexOf ('!');
+	File file = new File (path.substring (0, index));
+
+	try {
+		JarFile jar = new JarFile (file);
+		Manifest manifest = jar.getManifest ();
+		Attributes attributes = manifest.getMainAttributes ();
+		return Library.arch ().equals (attributes.getValue ("SWT-Arch")) && //$NON-NLS-1$
+				Library.os ().equals (attributes.getValue ("SWT-OS")); //$NON-NLS-1$
+	} catch (IOException e) {
+		/* should never happen for a valid SWT jar with the expected manifest values */
+	}
+
+	return false;	
+}
+
 }
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/SWT.java b/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/SWT.java
index 399bf07e82..fc2f81950e 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/SWT.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/SWT.java
@@ -4069,7 +4069,20 @@ public class SWT {
 	 */
 	public static final String SKIN_ID = "org.eclipse.swt.skin.id";
 
-	
+/**
+ * Returns a boolean indicating whether this SWT implementation can
+ * be loaded.  Examples of criteria that may be used to determine this
+ * include the OS and architecture of the JRE that is being used.
+ *
+ * @return <code>true</code> if this SWT implementation can be loaded
+ * and <code>false</code> otherwise
+ *
+ * @since 3.8
+ */
+public static boolean isLoadable () {
+	return Platform.IsLoadable ();
+}
+
 /**
  * Answers a concise, human readable description of the error code.
  *
diff --git a/bundles/org.eclipse.swt/buildFragment.xml b/bundles/org.eclipse.swt/buildFragment.xml
index a983168835..6363a9c71b 100644
--- a/bundles/org.eclipse.swt/buildFragment.xml
+++ b/bundles/org.eclipse.swt/buildFragment.xml
@@ -491,14 +491,24 @@
 			<param name="debug" value="true" />
 			<param name="jar.filename" value="swt-debug.jar" />
 		</antcall>
-		<jar jarfile="${build.result.folder}/swt-debug.jar" basedir="${fragmentdir}" update="true" includes="swt*.dll,libswt*.so,libswt*.sl,libswt*.a,libswt*.jnilib,libXm.so.2" />
+		<jar jarfile="${build.result.folder}/swt-debug.jar" basedir="${fragmentdir}" update="true" includes="swt*.dll,libswt*.so,libswt*.sl,libswt*.a,libswt*.jnilib,libXm.so.2">
+			<manifest>
+				<attribute name="SWT-OS" value="${swt.os}"/>
+				<attribute name="SWT-Arch" value="${swt.arch}"/>
+			</manifest>
+		</jar>
 		<copy file="${build.result.folder}/swt-debug.jar" todir="${temp.folder}/swtdownload" />
 		<delete dir="${build.result.folder}/@dot" />
 		<antcall target="build.jars">
 			<param name="debug" value="false" />
 			<param name="jar.filename" value="swt.jar" />
 		</antcall>
-		<jar jarfile="${build.result.folder}/swt.jar" basedir="${fragmentdir}" update="true" includes="swt*.dll,libswt*.so,libswt*.sl,libswt*.a,libswt*.jnilib,libXm.so.2" />
+		<jar jarfile="${build.result.folder}/swt.jar" basedir="${fragmentdir}" update="true" includes="swt*.dll,libswt*.so,libswt*.sl,libswt*.a,libswt*.jnilib,libXm.so.2">
+			<manifest>
+				<attribute name="SWT-OS" value="${swt.os}"/>
+				<attribute name="SWT-Arch" value="${swt.arch}"/>
+			</manifest>
+		</jar>
 		<copy file="${build.result.folder}/swt.jar" todir="${temp.folder}/swtdownload" />
 		<antcall target="build.sources" />
 		<copy file="${build.result.folder}/src.zip" todir="${temp.folder}/swtdownload" />
@@ -553,7 +563,12 @@
 		<antcall target="gather.bin.parts">
 			<param name="destination.temp.folder" value="${temp.folder}/" />
 		</antcall>
-		<jar jarfile="${plugin.destination}/${full.name}.jar" basedir="${temp.folder}/${full.name}" filesonly="true" manifest="${fragmentdir}/META-INF/MANIFEST.MF"/>
+		<jar jarfile="${plugin.destination}/${full.name}.jar" basedir="${temp.folder}/${full.name}" filesonly="true" manifest="${fragmentdir}/META-INF/MANIFEST.MF">
+	        <manifest>
+	            <attribute name="SWT-OS" value="${swt.os}"/>
+	            <attribute name="SWT-Arch" value="${swt.arch}"/>
+	        </manifest>
+		</jar>
 		<delete dir="${temp.folder}" />
 	</target>