Make layoutlib more lenient with recoverable errors

In many cases, throwing an exception will stop the inflation or
rendering of a layout. Sometimes, we could recover from some of the
failures and render a layout that is "usable".
I've done a first pass trying to follow the following rules:
 - Try simple recoveries by choosing sensible defaults. Not trying
 complex recoveries.
 - Only recover if the exception is not part of the class behaviour.
 Avoided removing declared exceptions or exceptions that are expected by
 the framework.
 - I've kept assertions in place so, in most cases, the behaviour will
 be almost identical to the previous one with assertions enabled.

Test: Checked with existing tests
Change-Id: I0001fdd3c808cf405c4eb8d734b9bbe63493e05c

tools/layoutlib/bridge/src/android/content/res/BridgeTypedArray.java

@@ -740,9 +740,11 @@ public final class BridgeTypedArray extends TypedArray {
         }
         int id = getResourceId(index, 0);
         String resIdMessage = id > 0 ? " (resource id 0x" + Integer.toHexString(id) + ')' : "";
-        throw new NotFoundException(
-                String.format("%1$s in %2$s%3$s is not a valid array resource.",
-                        resVal.getValue(), mNames[index], resIdMessage));
+        assert false :
+                String.format("%1$s in %2$s%3$s is not a valid array resource.", resVal.getValue(),
+                        mNames[index], resIdMessage);
+
+        return new CharSequence[0];
     }
 
     @Override

tools/layoutlib/bridge/src/android/graphics/BlendComposite.java

@@ -88,8 +88,9 @@ public final class BlendComposite implements Composite {
 
     private void setAlpha(float alpha) {
         if (alpha < 0.0f || alpha > 1.0f) {
-            throw new IllegalArgumentException(
-                    "alpha must be comprised between 0.0f and 1.0f");
+            assert false : "alpha must be comprised between 0.0f and 1.0f";
+            alpha = Math.min(alpha, 1.0f);
+            alpha = Math.max(alpha, 0.0f);
         }
 
         this.alpha = alpha;
@@ -266,9 +267,21 @@ public final class BlendComposite implements Composite {
                             return result;
                         }
                     };
+                default:
+                    assert false : "Blender not implement for " + composite.getMode().name();
+
+                    // Ignore the blend
+                    return new Blender() {
+                        @Override
+                        public int[] blend(int[] src, int[] dst, int[] result) {
+                            result[0] = dst[0];
+                            result[1] = dst[1];
+                            result[2] = dst[2];
+                            result[3] = dst[3];
+                            return result;
+                        }
+                    };
             }
-            throw new IllegalArgumentException("Blender not implement for " +
-                                               composite.getMode().name());
         }
     }
 }

tools/layoutlib/bridge/src/android/graphics/FontFamily_Delegate.java

@@ -252,7 +252,8 @@ public class FontFamily_Delegate {
     /*package*/ static boolean addFont(FontFamily thisFontFamily, String path, int ttcIndex,
             FontConfig.Axis[] axes, int weight, int italic) {
         if (thisFontFamily.mBuilderPtr == 0) {
-            throw new IllegalStateException("Unable to call addFont after freezing.");
+            assert false : "Unable to call addFont after freezing.";
+            return false;
         }
         final FontFamily_Delegate delegate = getDelegate(thisFontFamily.mBuilderPtr);
         return delegate != null && delegate.addFont(path, ttcIndex, weight, italic);

tools/layoutlib/bridge/src/android/graphics/Gradient_Delegate.java

@@ -49,21 +49,19 @@ public abstract class Gradient_Delegate extends Shader_Delegate {
      */
     protected Gradient_Delegate(long nativeMatrix, int colors[], float positions[]) {
         super(nativeMatrix);
-        if (colors.length < 2) {
-            throw new IllegalArgumentException("needs >= 2 number of colors");
-        }
-        if (positions != null && colors.length != positions.length) {
-            throw new IllegalArgumentException("color and position arrays must be of equal length");
-        }
+        assert colors.length >= 2 : "needs >= 2 number of colors";
 
         if (positions == null) {
             float spacing = 1.f / (colors.length - 1);
             positions = new float[colors.length];
             positions[0] = 0.f;
-            positions[colors.length-1] = 1.f;
-            for (int i = 1; i < colors.length - 1 ; i++) {
+            positions[colors.length - 1] = 1.f;
+            for (int i = 1; i < colors.length - 1; i++) {
                 positions[i] = spacing * i;
             }
+        } else {
+            assert colors.length == positions.length :
+                    "color and position " + "arrays must be of equal length";
         }
 
         mColors = colors;

tools/layoutlib/bridge/src/android/graphics/Path_Delegate.java

@@ -548,10 +548,11 @@ public final class Path_Delegate {
             case EVEN_ODD:
             case INVERSE_EVEN_ODD:
                 return GeneralPath.WIND_EVEN_ODD;
-        }
 
-        assert false;
-        throw new IllegalArgumentException();
+            default:
+                assert false;
+                return GeneralPath.WIND_NON_ZERO;
+        }
     }
 
     @NonNull

tools/layoutlib/bridge/src/android/graphics/RoundRectangle.java

@@ -61,10 +61,8 @@ public class RoundRectangle extends RectangularShape {
      * ellipse that corner is a quarter of.
      */
     public RoundRectangle(float x, float y, float width, float height, float[] cornerDimensions) {
-        if (cornerDimensions.length != 8) {
-            throw new IllegalArgumentException("The array of corner dimensions must have eight " +
-                    "elements");
-        }
+        assert cornerDimensions.length == 8 : "The array of corner dimensions must have eight " +
+                    "elements";
 
         this.x = x;
         this.y = y;

tools/layoutlib/bridge/src/android/graphics/drawable/VectorDrawable_Delegate.java

@@ -585,8 +585,8 @@ public class VectorDrawable_Delegate {
                     return this::setTrimPathOffset;
             }
 
-            throw new IllegalArgumentException("Invalid VFullPath_Delegate property index "
-                    + propertyIdx);
+            assert false : ("Invalid VFullPath_Delegate property index " + propertyIdx);
+            return t -> {};
         }
 
         @NonNull
@@ -598,8 +598,8 @@ public class VectorDrawable_Delegate {
                     return this::setFillColor;
             }
 
-            throw new IllegalArgumentException("Invalid VFullPath_Delegate property index "
-                    + propertyIdx);
+            assert false : ("Invalid VFullPath_Delegate property index " + propertyIdx);
+            return t -> {};
         }
 
         /////////////////////////////////////////////////////
@@ -827,8 +827,8 @@ public class VectorDrawable_Delegate {
                     return this::setTranslateY;
             }
 
-            throw new IllegalArgumentException("Invalid VGroup_Delegate property index "
-                    + propertyIdx);
+            assert false : ("Invalid VGroup_Delegate property index " + propertyIdx);
+            return t -> {};
         }
 
         /////////////////////////////////////////////////////

tools/layoutlib/bridge/src/android/text/StaticLayout_Delegate.java

@@ -164,7 +164,9 @@ public class StaticLayout_Delegate {
                         builder.mTabStopCalculator);
                 break;
             default:
-                throw new AssertionError("Unknown break strategy: " + builder.mBreakStrategy);
+                assert false : "Unknown break strategy: " + builder.mBreakStrategy;
+                builder.mLineBreaker = new GreedyLineBreaker(primitives, builder.mLineWidth,
+                        builder.mTabStopCalculator);
         }
         builder.mLineBreaker.computeBreaks(recycle);
         return recycle.breaks.length;

tools/layoutlib/bridge/src/android/util/PathParser_Delegate.java

@@ -361,7 +361,8 @@ public class PathParser_Delegate {
             }
             return Arrays.copyOf(results, count);
         } catch (NumberFormatException e) {
-            throw new RuntimeException("error in parsing \"" + s + "\"", e);
+            assert false : "error in parsing \"" + s + "\"" + e;
+            return new float[0];
         }
     }
 

tools/layoutlib/bridge/src/android/view/LayoutInflater_Delegate.java

@@ -16,6 +16,8 @@
 
 package android.view;
 
+import com.android.ide.common.rendering.api.LayoutLog;
+import com.android.layoutlib.bridge.Bridge;
 import com.android.tools.layoutlib.annotations.LayoutlibDelegate;
 
 import org.xmlpull.v1.XmlPullParser;
@@ -104,8 +106,10 @@ public class LayoutInflater_Delegate {
             if (layout == 0) {
                 final String value = attrs.getAttributeValue(null, ATTR_LAYOUT);
                 if (value == null || value.length() <= 0) {
-                    throw new InflateException("You must specify a layout in the"
-                            + " include tag: <include layout=\"@layout/layoutID\" />");
+                    Bridge.getLog().error(LayoutLog.TAG_BROKEN, "You must specify a layout in the"
+                            + " include tag: <include layout=\"@layout/layoutID\" />", null);
+                    LayoutInflater.consumeChildElements(parser);
+                    return;
                 }
 
                 // Attempt to resolve the "?attr/name" string to an identifier.
@@ -125,11 +129,11 @@ public class LayoutInflater_Delegate {
             if (layout == 0) {
                 final String value = attrs.getAttributeValue(null, ATTR_LAYOUT);
                 if (value == null) {
-                    throw new InflateException("You must specifiy a layout in the"
-                            + " include tag: <include layout=\"@layout/layoutID\" />");
+                    Bridge.getLog().error(LayoutLog.TAG_BROKEN, "You must specify a layout in the"
+                            + " include tag: <include layout=\"@layout/layoutID\" />", null);
                 } else {
-                    throw new InflateException("You must specifiy a valid layout "
-                            + "reference. The layout ID " + value + " is not valid.");
+                    Bridge.getLog().error(LayoutLog.TAG_BROKEN, "You must specify a valid layout "
+                            + "reference. The layout ID " + value + " is not valid.", null);
                 }
             } else {
                 final XmlResourceParser childParser =
@@ -144,8 +148,11 @@ public class LayoutInflater_Delegate {
                     }
 
                     if (type != XmlPullParser.START_TAG) {
-                        throw new InflateException(childParser.getPositionDescription() +
-                                ": No start tag found!");
+                        Bridge.getLog().error(LayoutLog.TAG_BROKEN,
+                                childParser.getPositionDescription() + ": No start tag found!",
+                                null);
+                        LayoutInflater.consumeChildElements(parser);
+                        return;
                     }
 
                     final String childName = childParser.getName();
@@ -219,7 +226,9 @@ public class LayoutInflater_Delegate {
                 }
             }
         } else {
-            throw new InflateException("<include /> can only be used inside of a ViewGroup");
+            Bridge.getLog().error(LayoutLog.TAG_BROKEN,
+                    "<include /> can only be used inside of a ViewGroup",
+                    null);
         }
 
         LayoutInflater.consumeChildElements(parser);

tools/layoutlib/bridge/src/android/view/RectShadowPainter.java

@@ -37,7 +37,8 @@ public class RectShadowPainter {
             @NonNull Canvas canvas) {
         Rect outline = new Rect();
         if (!viewOutline.getRect(outline)) {
-            throw new IllegalArgumentException("Outline is not a rect shadow");
+            assert false : "Outline is not a rect shadow";
+            return;
         }
 
         Rect originCanvasRect = canvas.getClipBounds();

tools/layoutlib/bridge/src/com/android/layoutlib/bridge/android/BridgeContext.java

@@ -652,7 +652,8 @@ public class BridgeContext extends Context {
             return null;
         }
 
-        throw new UnsupportedOperationException("Unsupported Service: " + service);
+        assert false : "Unsupported Service: " + service;
+        return null;
     }
 
     @Override
@@ -682,7 +683,9 @@ public class BridgeContext extends Context {
             }
 
             if (style == null) {
-                throw new Resources.NotFoundException();
+                Bridge.getLog().error(LayoutLog.TAG_RESOURCES_RESOLVE,
+                        "Failed to find style with " + resId, null);
+                return null;
             }
         }
 

tools/layoutlib/bridge/src/com/android/layoutlib/bridge/android/BridgePackageManager.java

@@ -49,6 +49,7 @@ import android.content.pm.VersionedPackage;
 import android.content.res.Resources;
 import android.content.res.XmlResourceParser;
 import android.graphics.Rect;
+import android.graphics.drawable.ColorDrawable;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.os.Handler;
@@ -307,7 +308,8 @@ public class BridgePackageManager extends PackageManager {
 
     @Override
     public Drawable getInstantAppIcon(String packageName) {
-        throw new UnsupportedOperationException();
+        assert false : "Unsupported operation";
+        return new ColorDrawable();
     }
 
     @Override

tools/layoutlib/bridge/src/com/android/layoutlib/bridge/bars/BridgeActionBar.java

@@ -21,6 +21,7 @@ import com.android.ide.common.rendering.api.ActionBarCallback.HomeButtonStyle;
 import com.android.ide.common.rendering.api.RenderResources;
 import com.android.ide.common.rendering.api.ResourceValue;
 import com.android.ide.common.rendering.api.SessionParams;
+import com.android.layoutlib.bridge.MockView;
 import com.android.layoutlib.bridge.android.BridgeContext;
 
 import android.annotation.NonNull;
@@ -53,35 +54,41 @@ public abstract class BridgeActionBar {
         mParams = params;
         mCallback = params.getLayoutlibCallback().getActionBarCallback();
         ResourceValue layoutName = getLayoutResource(context);
-        if (layoutName == null) {
-            throw new RuntimeException("Unable to find the layout for Action Bar.");
-        }
-        int layoutId;
-        if (layoutName.isFramework()) {
-            layoutId = context.getFrameworkResourceValue(layoutName.getResourceType(),
-                    layoutName.getName(), 0);
-        } else {
-            layoutId = context.getProjectResourceValue(layoutName.getResourceType(),
-                    layoutName.getName(), 0);
 
+        int layoutId = 0;
+        if (layoutName == null) {
+            assert false : "Unable to find the layout for Action Bar.";
+        }
+        else {
+            if (layoutName.isFramework()) {
+                layoutId = context.getFrameworkResourceValue(layoutName.getResourceType(),
+                        layoutName.getName(), 0);
+            } else {
+                layoutId = context.getProjectResourceValue(layoutName.getResourceType(),
+                        layoutName.getName(), 0);
+
+            }
         }
         if (layoutId == 0) {
-            throw new RuntimeException(
-                    String.format("Unable to resolve attribute \"%1$s\" of type \"%2$s\"",
-                            layoutName.getName(), layoutName.getResourceType()));
-        }
-        if (mCallback.isOverflowPopupNeeded()) {
-            // Create a RelativeLayout around the action bar, to which the overflow popup may be
-            // added.
-            mEnclosingLayout = new RelativeLayout(mBridgeContext);
-            setMatchParent(mEnclosingLayout);
-        } else {
+            assert false : String.format("Unable to resolve attribute \"%1$s\" of type \"%2$s\"",
+                    layoutName.getName(), layoutName.getResourceType());
+            mDecorContent = new MockView(context);
             mEnclosingLayout = null;
         }
+        else {
+            if (mCallback.isOverflowPopupNeeded()) {
+                // Create a RelativeLayout around the action bar, to which the overflow popup may be
+                // added.
+                mEnclosingLayout = new RelativeLayout(mBridgeContext);
+                setMatchParent(mEnclosingLayout);
+            } else {
+                mEnclosingLayout = null;
+            }
 
-        // Inflate action bar layout.
-        mDecorContent =
-                getInflater(context).inflate(layoutId, mEnclosingLayout, mEnclosingLayout != null);
+            // Inflate action bar layout.
+            mDecorContent = getInflater(context).inflate(layoutId, mEnclosingLayout,
+                    mEnclosingLayout != null);
+        }
     }
 
     /**

tools/layoutlib/bridge/src/com/android/layoutlib/bridge/bars/CustomBar.java

@@ -83,18 +83,18 @@ abstract class CustomBar extends LinearLayout {
         XmlPullParser parser;
         try {
             parser = ParserFactory.create(getClass().getResourceAsStream(layoutPath), name);
+
+            BridgeXmlBlockParser bridgeParser = new BridgeXmlBlockParser(parser, context, false);
+
+            try {
+                inflater.inflate(bridgeParser, this, true);
+            } finally {
+                bridgeParser.ensurePopped();
+            }
         } catch (XmlPullParserException e) {
             // Should not happen as the resource is bundled with the jar, and  ParserFactory should
             // have been initialized.
-            throw new AssertionError(e);
-        }
-
-        BridgeXmlBlockParser bridgeParser = new BridgeXmlBlockParser(parser, context, false);
-
-        try {
-            inflater.inflate(bridgeParser, this, true);
-        } finally {
-            bridgeParser.ensurePopped();
+            assert false;
         }
     }
 

tools/layoutlib/bridge/src/com/android/layoutlib/bridge/bars/FrameworkActionBar.java

@@ -176,7 +176,8 @@ public class FrameworkActionBar extends BridgeActionBar {
         ArrayList<MenuItemImpl> menus = mActionBar.getMenuBuilder().getNonActionItems();
         ActionMenuPresenter presenter = mActionBar.getActionMenuPresenter();
         if (presenter == null) {
-            throw new RuntimeException("Failed to create a Presenter for Action Bar Menus.");
+            assert false : "Failed to create a Presenter for Action Bar Menus.";
+            return false;
         }
         if (presenter.isOverflowReserved() &&
                 menus != null) {

tools/layoutlib/bridge/src/com/android/layoutlib/bridge/impl/ResourceHelper.java

@@ -43,6 +43,7 @@ import android.content.res.GradientColor;
 import android.content.res.Resources.Theme;
 import android.graphics.Bitmap;
 import android.graphics.Bitmap_Delegate;
+import android.graphics.Color;
 import android.graphics.NinePatch_Delegate;
 import android.graphics.Rect;
 import android.graphics.Typeface;
@@ -184,7 +185,8 @@ public final class ResourceHelper {
                     }
 
                     if (type != XmlPullParser.START_TAG) {
-                        throw new XmlPullParserException("No start tag found");
+                        assert false : "No start tag found";
+                        return null;
                     }
 
                     final String name = blockParser.getName();