Handle fragment tags in included contexts

This changeset fixes the support for rendering user-chosen layouts in
<fragment> tags in a couple of scenarios:
- where the fragment is part of a layout that "surrounds" the current
  layout (e.g. "show included in")
- where the fragment is part of a layout that is included from the
  edited layout

In both cases, the fragment is read from a layout that is parsed with
a plain pull parser rather than the full XML node model used for
edited layouts, so to fix this the ContextPullParser now looks
specially for <fragment> tags and handles these specially.

In the second scenario, the parser is constructed by layoutlib, so we
have to use the project callback to anticipate requested parsers and
supply our own fragment-capable pull parsers instead.

Change-Id: I8aba253ac0c1a0d5dad7bc6efb9def5f20c75144

5 files changed, 187 insertions, 34 deletions

diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/ContextPullParser.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/ContextPullParser.java
index 7c40097..bd1ac81 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/ContextPullParser.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/ContextPullParser.java
@@ -20,28 +20,45 @@ import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_HEIGHT;
 import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_WIDTH;
 import static com.android.ide.common.layout.LayoutConstants.VALUE_FILL_PARENT;
 import static com.android.ide.common.layout.LayoutConstants.VALUE_MATCH_PARENT;
+import static com.android.ide.eclipse.adt.internal.editors.layout.descriptors.LayoutDescriptors.ATTR_LAYOUT;
+import static com.android.ide.eclipse.adt.internal.editors.layout.descriptors.LayoutDescriptors.VIEW_FRAGMENT;
+import static com.android.ide.eclipse.adt.internal.editors.layout.descriptors.LayoutDescriptors.VIEW_INCLUDE;
+import static com.android.ide.eclipse.adt.internal.editors.layout.gle2.LayoutMetadata.KEY_FRAGMENT_LAYOUT;
 
 import com.android.ide.common.rendering.api.ILayoutPullParser;
 import com.android.ide.common.rendering.api.IProjectCallback;
-import com.android.layoutlib.api.IXmlPullParser;
+import com.android.ide.eclipse.adt.AdtPlugin;
+import com.android.ide.eclipse.adt.internal.editors.layout.gle2.LayoutMetadata;
 import com.android.sdklib.SdkConstants;
 
 import org.kxml2.io.KXmlParser;
+import org.xmlpull.v1.XmlPullParserException;
+
+import java.io.File;
 
 /**
- * Modified {@link KXmlParser} that adds the methods of {@link ILayoutPullParser}.
+ * Modified {@link KXmlParser} that adds the methods of {@link ILayoutPullParser}, and
+ * performs other layout-specific parser behavior like translating fragment tags into
+ * include tags.
  * <p/>
  * It will return a given parser when queried for one through
- * {@link IXmlPullParser#getParser(String)} for a given name.
+ * {@link ILayoutPullParser#getParser(String)} for a given name.
  *
  */
 public class ContextPullParser extends KXmlParser implements ILayoutPullParser {
-
+    private static final String COMMENT_PREFIX = "<!--"; //$NON-NLS-1$
+    private static final String COMMENT_SUFFIX = "-->"; //$NON-NLS-1$
+    /** The callback to request parsers from */
     private final IProjectCallback mProjectCallback;
+    /** The {@link File} for the layout currently being parsed */
+    private File mFile;
+    /** The layout to be shown for the current {@code <fragment>} tag. Usually null. */
+    private String mFragmentLayout = null;
 
-    public ContextPullParser(IProjectCallback projectCallback) {
+    public ContextPullParser(IProjectCallback projectCallback, File file) {
         super();
         mProjectCallback = projectCallback;
+        mFile = file;
     }
 
     // --- Layout lib API methods
@@ -62,7 +79,28 @@ public class ContextPullParser extends KXmlParser implements ILayoutPullParser {
     // --- KXMLParser override
 
     @Override
+    public String getName() {
+        String name = super.getName();
+
+        // At designtime, replace fragments with includes.
+        if (name.equals(VIEW_FRAGMENT)) {
+            mFragmentLayout = findFragmentLayout();
+            if (mFragmentLayout != null) {
+                return VIEW_INCLUDE;
+            }
+        } else {
+            mFragmentLayout = null;
+        }
+
+        return name;
+    }
+
+    @Override
     public String getAttributeValue(String namespace, String localName) {
+        if (localName.equals(ATTR_LAYOUT) && mFragmentLayout != null) {
+            return mFragmentLayout;
+        }
+
         String value = super.getAttributeValue(namespace, localName);
 
         // on the fly convert match_parent to fill_parent for compatibility with older
@@ -76,4 +114,58 @@ public class ContextPullParser extends KXmlParser implements ILayoutPullParser {
 
         return value;
     }
+
+    /**
+     * This method determines whether the {@code <fragment>} tag in the current parsing
+     * context has been configured with a layout to render at designtime. If so,
+     * it returns the resource name of the layout, and if not, returns null.
+     */
+    private String findFragmentLayout() {
+        try {
+            if (!isEmptyElementTag()) {
+                // We need to look inside the <fragment> tag to see
+                // if it contains a comment which indicates a fragment
+                // to be rendered.
+                String file = AdtPlugin.readFile(mFile);
+
+                int line = getLineNumber() - 1;
+                int column = getColumnNumber() - 1;
+                int offset = 0;
+                int currentLine = 0;
+                int length = file.length();
+                while (currentLine < line && offset < length) {
+                    int next = file.indexOf('\n', offset);
+                    if (next == -1) {
+                        break;
+                    }
+
+                    currentLine++;
+                    offset = next + 1;
+                }
+                if (currentLine == line) {
+                    offset += column;
+                    if (offset < length) {
+                        offset = file.indexOf('<', offset);
+                        if (offset != -1 && file.startsWith(COMMENT_PREFIX, offset)) {
+                            // The fragment tag contains a comment
+                            int end = file.indexOf(COMMENT_SUFFIX, offset);
+                            if (end != -1) {
+                                String commentText = file.substring(
+                                        offset + COMMENT_PREFIX.length(), end);
+                                String l = LayoutMetadata.getProperty(KEY_FRAGMENT_LAYOUT,
+                                        commentText);
+                                if (l != null) {
+                                    return l;
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        } catch (XmlPullParserException e) {
+            AdtPlugin.log(e, null);
+        }
+
+        return null;
+    }
 }
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/ProjectCallback.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/ProjectCallback.java
index c3698fd..c71005c 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/ProjectCallback.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/ProjectCallback.java
@@ -34,6 +34,7 @@ import com.android.ide.common.rendering.api.ResourceReference;
 import com.android.ide.common.rendering.api.ResourceValue;
 import com.android.ide.common.rendering.api.Result;
 import com.android.ide.common.rendering.legacy.LegacyCallback;
+import com.android.ide.common.resources.ResourceResolver;
 import com.android.ide.eclipse.adt.AdtConstants;
 import com.android.ide.eclipse.adt.AdtPlugin;
 import com.android.ide.eclipse.adt.internal.editors.layout.gle2.LayoutMetadata;
@@ -47,7 +48,12 @@ import com.android.sdklib.xml.ManifestData;
 import com.android.util.Pair;
 
 import org.eclipse.core.resources.IProject;
+import org.xmlpull.v1.XmlPullParser;
+import org.xmlpull.v1.XmlPullParserException;
 
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
@@ -58,7 +64,7 @@ import java.util.TreeSet;
 /**
  * Loader for Android Project class in order to use them in the layout editor.
  * <p/>This implements {@link IProjectCallback} for the old and new API through
- * {@link ILegacyCallback}
+ * {@link LegacyCallback}
  */
 public final class ProjectCallback extends LegacyCallback {
     private final HashMap<String, Class<?>> mLoadedClasses = new HashMap<String, Class<?>>();
@@ -75,7 +81,7 @@ public final class ProjectCallback extends LegacyCallback {
 
     private String mLayoutName;
     private ILayoutPullParser mLayoutEmbeddedParser;
-
+    private ResourceResolver mResourceResolver;
 
     /**
      * Creates a new {@link ProjectCallback} to be used with the layout lib.
@@ -396,15 +402,51 @@ public final class ProjectCallback extends LegacyCallback {
     }
 
     public ILayoutPullParser getParser(String layoutName) {
-        if (layoutName.equals(mLayoutName)) {
-            return mLayoutEmbeddedParser;
+        // Try to compute the ResourceValue for this layout since layoutlib
+        // must be an older version which doesn't pass the value:
+        if (mResourceResolver != null) {
+            ResourceValue value = mResourceResolver.getProjectResource(ResourceType.LAYOUT,
+                    layoutName);
+            if (value != null) {
+                return getParser(value);
+            }
         }
 
-        return null;
+        return getParser(layoutName, null);
     }
 
     public ILayoutPullParser getParser(ResourceValue layoutResource) {
-        return getParser(layoutResource.getName());
+        return getParser(layoutResource.getName(),
+                new File(layoutResource.getValue()));
+    }
+
+    private ILayoutPullParser getParser(String layoutName, File xml) {
+        if (layoutName.equals(mLayoutName)) {
+            ILayoutPullParser parser = mLayoutEmbeddedParser;
+            // The parser should only be used once!! If it is included more than once,
+            // subsequent includes should just use a plain pull parser that is not tied
+            // to the XML model
+            mLayoutEmbeddedParser = null;
+            return parser;
+        }
+
+        // For included layouts, create a ContextPullParser such that we get the
+        // layout editor behavior in included layouts as well - which for example
+        // replaces <fragment> tags with <include>.
+        if (xml != null && xml.isFile()) {
+            ContextPullParser parser = new ContextPullParser(this, xml);
+            try {
+                parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true);
+                parser.setInput(new FileInputStream(xml), "UTF-8"); //$NON-NLS-1$
+                return parser;
+            } catch (XmlPullParserException e) {
+                AdtPlugin.log(e, null);
+            } catch (FileNotFoundException e) {
+                // Shouldn't happen since we check isFile() above
+            }
+        }
+
+        return null;
     }
 
     public Object getAdapterItemValue(ResourceReference adapterView, Object adapterCookie,
@@ -543,4 +585,13 @@ public final class ProjectCallback extends LegacyCallback {
 
         return binding;
     }
+
+    /**
+     * Sets the {@link ResourceResolver} to be used when looking up resources
+     *
+     * @param resolver the resolver to use
+     */
+    public void setResourceResolver(ResourceResolver resolver) {
+        mResourceResolver = resolver;
+    }
 }
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/GraphicalEditorPart.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/GraphicalEditorPart.java
index 5d0f5b6..e3d484d 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/GraphicalEditorPart.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/GraphicalEditorPart.java
@@ -220,16 +220,10 @@ public class GraphicalEditorPart extends EditorPart
     private Map<ResourceType, Map<String, ResourceValue>> mConfiguredProjectRes;
     private ProjectCallback mProjectCallback;
     private boolean mNeedsRecompute = false;
-
     private TargetListener mTargetListener;
-
     private ConfigListener mConfigListener;
     private ResourceResolver mResourceResolver;
-
     private ReloadListener mReloadListener;
-
-    private boolean mUseExplodeMode;
-
     private int mMinSdkVersion;
     private int mTargetSdkVersion;
     private LayoutActionBar mActionBar;
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/LayoutMetadata.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/LayoutMetadata.java
index d2c4985..906a2ec 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/LayoutMetadata.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/LayoutMetadata.java
@@ -98,22 +98,7 @@ public class LayoutMetadata {
             Node comment = findComment(node);
             if (comment != null) {
                 String text = comment.getNodeValue();
-                assert text.startsWith(COMMENT_PROLOGUE);
-                String valuesString = text.substring(COMMENT_PROLOGUE.length());
-                String[] values = valuesString.split(","); //$NON-NLS-1$
-                if (values.length == 1) {
-                    valuesString = values[0].trim();
-                    if (valuesString.indexOf('\n') != -1) {
-                        values = valuesString.split("\n"); //$NON-NLS-1$
-                    }
-                }
-                String target = name + '=';
-                for (int j = 0; j < values.length; j++) {
-                    String value = values[j].trim();
-                    if (value.startsWith(target)) {
-                        return value.substring(target.length()).trim();
-                    }
-                }
+                return getProperty(name, text);
             }
 
             return null;
@@ -125,6 +110,33 @@ public class LayoutMetadata {
     }
 
     /**
+     * Returns the given property specified in the given XML comment
+     *
+     * @param name the name of the property to look up
+     * @param text the comment text for an XML node
+     * @return the value stored with the given node and name, or null
+     */
+    public static String getProperty(String name, String text) {
+        assert text.startsWith(COMMENT_PROLOGUE);
+        String valuesString = text.substring(COMMENT_PROLOGUE.length());
+        String[] values = valuesString.split(","); //$NON-NLS-1$
+        if (values.length == 1) {
+            valuesString = values[0].trim();
+            if (valuesString.indexOf('\n') != -1) {
+                values = valuesString.split("\n"); //$NON-NLS-1$
+            }
+        }
+        String target = name + '=';
+        for (int j = 0; j < values.length; j++) {
+            String value = values[j].trim();
+            if (value.startsWith(target)) {
+                return value.substring(target.length()).trim();
+            }
+        }
+        return null;
+    }
+
+    /**
      * Sets the given property of the given DOM node to a given value, or if null clears
      * the property.
      *
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/RenderService.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/RenderService.java
index 36cea84..a03d038 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/RenderService.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/RenderService.java
@@ -320,7 +320,7 @@ public class RenderService {
                         // as it's what IXmlPullParser.getParser(String) will receive.
                         String queryLayoutName = mEditor.getLayoutResourceName();
                         mProjectCallback.setLayoutParser(queryLayoutName, modelParser);
-                        topParser = new ContextPullParser(mProjectCallback);
+                        topParser = new ContextPullParser(mProjectCallback, layoutFile);
                         topParser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true);
                         topParser.setInput(new FileInputStream(layoutFile), "UTF-8"); //$NON-NLS-1$
                     } catch (XmlPullParserException e) {
@@ -376,6 +376,7 @@ public class RenderService {
 
         try {
             mProjectCallback.setLogger(mLogger);
+            mProjectCallback.setResourceResolver(mResourceResolver);
             return mLayoutLib.createSession(params);
         } catch (RuntimeException t) {
             // Exceptions from the bridge
@@ -383,6 +384,7 @@ public class RenderService {
             throw t;
         } finally {
             mProjectCallback.setLogger(null);
+            mProjectCallback.setResourceResolver(null);
         }
     }
 
@@ -482,6 +484,7 @@ public class RenderService {
         RenderSession session = null;
         try {
             mProjectCallback.setLogger(mLogger);
+            mProjectCallback.setResourceResolver(mResourceResolver);
             session = mLayoutLib.createSession(params);
             if (session.getResult().isSuccess()) {
                 assert session.getRootViews().size() == 1;
@@ -506,6 +509,7 @@ public class RenderService {
             throw t;
         } finally {
             mProjectCallback.setLogger(null);
+            mProjectCallback.setResourceResolver(null);
             if (session != null) {
                 session.dispose();
             }