Fix platform access to LinkService

Author: ctrueden

src/main/java/org/scijava/desktop/links/DefaultLinkService.java

@@ -28,9 +28,16 @@
  */
 package org.scijava.desktop.links;
 
+import java.awt.Desktop;
+import java.net.URI;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+import org.scijava.desktop.DesktopIntegrationProvider;
 import org.scijava.event.ContextCreatedEvent;
 import org.scijava.event.EventHandler;
-import org.scijava.desktop.DesktopIntegrationProvider;
 import org.scijava.log.LogService;
 import org.scijava.platform.Platform;
 import org.scijava.platform.PlatformService;
@@ -39,11 +46,6 @@
 import org.scijava.plugin.Plugin;
 import org.scijava.service.Service;
 
-import java.awt.Desktop;
-import java.net.URI;
-import java.util.HashSet;
-import java.util.Set;
-
 /**
  * Default implementation of {@link LinkService}.
  *
@@ -58,6 +60,25 @@ public class DefaultLinkService extends AbstractHandlerService<URI, LinkHandler>
 	@Parameter(required = false)
 	private PlatformService platformService;
 
+	private final Set<String> extensions = new HashSet<>();
+
+	/**
+	 * Gets supported file extensions.
+	 */
+	@Override
+	public Set<String> getFileExtensions() {
+		return Collections.unmodifiableSet(extensions);
+	}
+
+	/**
+	 * Gets supported file extensions.
+	 */
+	@Override
+	public void addFileExtensions(final String... extensions) {
+		this.extensions.addAll(Arrays.asList(extensions));
+	}
+
+
 	@EventHandler
 	private void onEvent(final ContextCreatedEvent evt) {
 		// Register URI handler with the desktop system, if possible.

src/main/java/org/scijava/desktop/links/LinkService.java

@@ -28,13 +28,15 @@
  */
 package org.scijava.desktop.links;
 
+import java.net.URI;
+import java.util.HashSet;
+import java.util.Optional;
+import java.util.Set;
+
 import org.scijava.log.Logger;
 import org.scijava.plugin.HandlerService;
 import org.scijava.service.SciJavaService;
 
-import java.net.URI;
-import java.util.Optional;
-
 /**
  * Service interface for handling URIs.
  *
@@ -45,6 +47,16 @@ public interface LinkService extends HandlerService<URI, LinkHandler>,
 	SciJavaService
 {
 
+	/**
+	 * Gets the set of supported file extensions.
+	 */
+	public Set<String> getFileExtensions();
+
+	/**
+	 * Adds to the set of supported file extensions.
+	 */
+	public void addFileExtensions(final String... extension);
+
 	default void handle(final URI uri) {
 		// Find the highest-priority link handler plugin which matches, if any.
 		final Optional<LinkHandler> match = getInstances().stream() //
@@ -60,6 +72,15 @@ default void handle(final URI uri) {
 		match.get().handle(uri);
 	}
 
+	default Set<String> getSchemes() {
+		var schemes = new HashSet<String>();
+		for (final LinkHandler handler : getInstances()) {
+			final var handlerSchemes = handler.getSchemes();
+			if (handlerSchemes != null) schemes.addAll(handlerSchemes);
+		}
+		return schemes;
+	}
+
 	// -- PTService methods --
 
 	@Override

src/main/java/org/scijava/desktop/platform/linux/LinuxPlatform.java

@@ -29,9 +29,9 @@
 
 package org.scijava.desktop.platform.linux;
 
+import org.scijava.Context;
 import org.scijava.app.AppService;
 import org.scijava.desktop.DesktopIntegrationProvider;
-import org.scijava.desktop.links.LinkHandler;
 import org.scijava.desktop.links.LinkService;
 import org.scijava.desktop.links.SchemeInstaller;
 import org.scijava.log.LogService;
@@ -47,9 +47,8 @@
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.nio.file.StandardOpenOption;
-import java.util.HashSet;
+import java.util.Collections;
 import java.util.LinkedHashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -74,7 +73,7 @@ public class LinuxPlatform extends AbstractPlatform
 {
 
 	@Parameter
-	private LinkService linkService;
+	private Context context;
 
 	@Parameter
 	private AppService appService;
@@ -120,20 +119,16 @@ public void open(final URL url) throws IOException {
 	public boolean isWebLinksEnabled() {
 		try {
 			final DesktopFile df = getOrCreateDesktopFile();
-			final Set<String> schemes = collectSchemes();
-			if (schemes.isEmpty()) return false;
 
 			// Check if any scheme is registered
-			for (final String scheme : schemes) {
+			for (final String scheme : schemes()) {
 				if (df.hasMimeType("x-scheme-handler/" + scheme)) return true;
 			}
-			return false;
-		} catch (final IOException e) {
-			if (log != null) {
-				log.debug("Failed to check web links status", e);
-			}
-			return false;
 		}
+		catch (final IOException e) {
+			if (log != null) log.debug("Failed to check web links status", e);
+		}
+		return false;
 	}
 
 	@Override
@@ -143,14 +138,10 @@ public boolean isWebLinksEnabled() {
 	public void setWebLinksEnabled(final boolean enable) throws IOException {
 		final DesktopFile df = getOrCreateDesktopFile();
 
-		final Set<String> schemes = collectSchemes();
-		for (final String scheme : schemes) {
+		for (final String scheme : schemes()) {
 			final String mimeType = "x-scheme-handler/" + scheme;
-			if (enable) {
-				df.addMimeType(mimeType);
-			} else {
-				df.removeMimeType(mimeType);
-			}
+			if (enable) df.addMimeType(mimeType);
+			else df.removeMimeType(mimeType);
 		}
 
 		df.save();
@@ -269,14 +260,13 @@ public void setFileExtensionsEnabled(final boolean enable) throws IOException {
 			// Remove file extension MIME types from .desktop file
 			// Keep URI scheme handlers (x-scheme-handler/...)
 			final DesktopFile df = getOrCreateDesktopFile();
-			final Set<String> uriSchemes = collectSchemes();
 
 			for (final String mimeType : mimeMapping.values()) {
 				df.removeMimeType(mimeType);
 			}
 
 			// Re-add URI scheme handlers
-			for (final String scheme : uriSchemes) {
+			for (final String scheme : schemes()) {
 				df.addMimeType("x-scheme-handler/" + scheme);
 			}
 
@@ -397,20 +387,23 @@ private String sanitizeFileName(final String name) {
 
 	// -- Helper methods --
 
-	/**
-	 * Collects all URI schemes from registered LinkHandler plugins.
-	 */
-	private Set<String> collectSchemes() {
-		final Set<String> schemes = new HashSet<>();
-		if (linkService == null) return schemes;
-
-		for (final LinkHandler handler : linkService.getInstances()) {
-			final List<String> handlerSchemes = handler.getSchemes();
-			if (handlerSchemes != null) {
-				schemes.addAll(handlerSchemes);
-			}
-		}
-		return schemes;
+	private LinkService linkService() {
+		// NB: We cannot declare LinkService as an @Parameter because
+		// the PlatformService creates its plugin singletons before the
+		// LinkService has been instantiated and added to the context.
+		return context.getService(LinkService.class);
+	}
+
+	private Set<String> schemes() {
+		final LinkService linkService = linkService();
+		return linkService == null ?
+			Collections.emptySet() : linkService.getSchemes();
+	}
+
+	private Set<String> extensions() {
+		final LinkService linkService = linkService();
+		return linkService == null ?
+			Collections.emptySet() : linkService.getFileExtensions();
 	}
 
 	/**
@@ -421,8 +414,8 @@ private synchronized Map<String, String> loadMimeTypeMapping() throws IOExceptio
 
 		extensionToMime = new LinkedHashMap<>();
 
-		// TODO: We need public API in LinkService for registering the extensions we want.
-		// TODO: Then, in fiji-links, we can use that API to plug in all the SCIFIO-supported file formats.
+		final Set<String> extensions = extensions();
+		// TODO: How do we know the MIME type of each extension?
 
 		return extensionToMime;
 	}