Do not grow the viewport width to infinite to fit

the content. Limit the overview viewport width to
a level that if a site behaves badly, the WebView
still does reasonably.

Partially fix http://b/issue?id=2209659
maps.yahoo.com keeps growing due to a layout bug.
This prevents the browser to go insane.

Partially fix http://b/issue?id=2215387
caltrain.com has a super long   which caused
the page super wide. This prevents the browser to
become unusable.

This change will make sites like, caltrain.com/timetable.html
not fit all in the view. You have to scroll left
and right. And it is same as iPhone.

2 files changed, 29 insertions, 11 deletions

diff --git a/core/java/android/webkit/WebView.java b/core/java/android/webkit/WebView.java
index 8b67162..5f7fdda 100644
--- a/core/java/android/webkit/WebView.java
+++ b/core/java/android/webkit/WebView.java
@@ -504,6 +504,16 @@ public class WebView extends AbsoluteLayout
         "REQUEST_KEYBOARD" //                = 27;
     };
 
+    // If the site doesn't use the viewport meta tag to specify the viewport,
+    // use DEFAULT_VIEWPORT_WIDTH as the default viewport width
+    static final int DEFAULT_VIEWPORT_WIDTH = 800;
+
+    // normally we try to fit the content to the minimum preferred width
+    // calculated by the Webkit. To avoid the bad behavior when some site's
+    // minimum preferred width keeps growing when changing the viewport width or
+    // the minimum preferred width is huge, an upper limit is needed.
+    static int sMaxViewportWidth = DEFAULT_VIEWPORT_WIDTH;
+
     // default scale limit. Depending on the display density
     private static float DEFAULT_MAX_ZOOM_SCALE;
     private static float DEFAULT_MIN_ZOOM_SCALE;
@@ -523,7 +533,7 @@ public class WebView extends AbsoluteLayout
 
     // ideally mZoomOverviewWidth should be mContentWidth. But sites like espn,
     // engadget always have wider mContentWidth no matter what viewport size is.
-    int mZoomOverviewWidth = WebViewCore.DEFAULT_VIEWPORT_WIDTH;
+    int mZoomOverviewWidth = DEFAULT_VIEWPORT_WIDTH;
     float mLastScale;
 
     // default scale. Depending on the display density.
@@ -3732,6 +3742,14 @@ public class WebView extends AbsoluteLayout
             mZoomCenterY = getViewHeight() * .5f;
         }
 
+        // adjust the max viewport width depending on the view dimensions. This
+        // is to ensure the scaling is not going insane. So do not shrink it if
+        // the view size is temporarily smaller, e.g. when soft keyboard is up.
+        int newMaxViewportWidth = (int) (Math.max(w, h) / DEFAULT_MIN_ZOOM_SCALE);
+        if (newMaxViewportWidth > sMaxViewportWidth) {
+            sMaxViewportWidth = newMaxViewportWidth;
+        }
+
         // update mMinZoomScale if the minimum zoom scale is not fixed
         if (!mMinZoomScaleFixed) {
             // when change from narrow screen to wide screen, the new viewWidth
@@ -5165,8 +5183,11 @@ public class WebView extends AbsoluteLayout
                         mPictureListener.onNewPicture(WebView.this, capturePicture());
                     }
                     if (useWideViewport) {
-                        mZoomOverviewWidth = Math.max(draw.mMinPrefWidth,
-                                draw.mViewPoint.x);
+                        // limit mZoomOverviewWidth to sMaxViewportWidth so that
+                        // if the page doesn't behave well, the WebView won't go
+                        // insane.
+                        mZoomOverviewWidth = Math.min(sMaxViewportWidth, Math
+                                .max(draw.mMinPrefWidth, draw.mViewPoint.x));
                     }
                     if (!mMinZoomScaleFixed) {
                         mMinZoomScale = (float) viewWidth / mZoomOverviewWidth;
diff --git a/core/java/android/webkit/WebViewCore.java b/core/java/android/webkit/WebViewCore.java
index 5460a47..e0e7897 100644
--- a/core/java/android/webkit/WebViewCore.java
+++ b/core/java/android/webkit/WebViewCore.java
@@ -124,10 +124,6 @@ final class WebViewCore {
     private int mWebkitScrollX = 0;
     private int mWebkitScrollY = 0;
 
-    // If the site doesn't use viewport meta tag to specify the viewport, use
-    // DEFAULT_VIEWPORT_WIDTH as default viewport width
-    static final int DEFAULT_VIEWPORT_WIDTH = 800;
-
     // The thread name used to identify the WebCore thread and for use in
     // debugging other classes that require operation within the WebCore thread.
     /* package */ static final String THREAD_NAME = "WebViewCoreThread";
@@ -1522,7 +1518,7 @@ final class WebViewCore {
             if (mViewportWidth == -1) {
                 if (mSettings.getLayoutAlgorithm() ==
                         WebSettings.LayoutAlgorithm.NORMAL) {
-                    width = DEFAULT_VIEWPORT_WIDTH;
+                    width = WebView.DEFAULT_VIEWPORT_WIDTH;
                 } else {
                     /*
                      * if a page's minimum preferred width is wider than the
@@ -1536,8 +1532,9 @@ final class WebViewCore {
                      * In the worse case, the native width will be adjusted when
                      * next zoom or screen orientation change happens.
                      */
-                    width = Math.max(w, Math.max(DEFAULT_VIEWPORT_WIDTH,
-                            nativeGetContentMinPrefWidth()));
+                    width = Math.min(WebView.sMaxViewportWidth, Math.max(w,
+                            Math.max(WebView.DEFAULT_VIEWPORT_WIDTH,
+                                    nativeGetContentMinPrefWidth())));
                 }
             } else {
                 width = Math.max(w, mViewportWidth);
@@ -1637,7 +1634,7 @@ final class WebViewCore {
             draw.mViewPoint = new Point(mCurrentViewWidth, mCurrentViewHeight);
             if (mSettings.getUseWideViewPort()) {
                 draw.mMinPrefWidth = Math.max(
-                        mViewportWidth == -1 ? DEFAULT_VIEWPORT_WIDTH
+                        mViewportWidth == -1 ? WebView.DEFAULT_VIEWPORT_WIDTH
                                 : (mViewportWidth == 0 ? mCurrentViewWidth
                                         : mViewportWidth),
                         nativeGetContentMinPrefWidth());