[WIP] WebRestrictions

components/web_restriction/java/src/org/chromium/components/webrestriction/ContentResolverWebRestrictionProvider.java

Index: components/web_restriction/java/src/org/chromium/components/webrestriction/ContentResolverWebRestrictionProvider.java
diff --git a/components/web_restriction/java/src/org/chromium/components/webrestriction/ContentResolverWebRestrictionProvider.java b/components/web_restriction/java/src/org/chromium/components/webrestriction/ContentResolverWebRestrictionProvider.java
new file mode 100644
index 0000000000000000000000000000000000000000..88af8a0011c5da8874f0ff781aea5f6de7ae788a
--- /dev/null
+++ b/components/web_restriction/java/src/org/chromium/components/webrestriction/ContentResolverWebRestrictionProvider.java
@@ -0,0 +1,90 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.components.webrestriction;
+
+import android.content.ContentResolver;
+import android.content.ContentValues;
+import android.database.Cursor;
+import android.net.Uri;
+import android.text.TextUtils;
+
+import org.chromium.base.ContextUtils;
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+
+/**
+ * This class acts as an interface that talks to the content provider which actually implements the
+ * web restriction provider.
+ */
+@JNINamespace("web_restriction::android")
+public class ContentResolverWebRestrictionProvider {
+    private final ContentResolver mContentResolver;
+
+    private final Uri mRequestUri;
+    private final Uri mQueryUri;
+    private boolean mSupportsRequest;
+
+    /**
+     * Start the web restriction provider and setup the content resolver.
+     */
+    private ContentResolverWebRestrictionProvider(String authority) {
+        assert !TextUtils.isEmpty(authority);
+        Uri baseUri = new Uri.Builder().scheme("content").authority(authority).build();
+        mContentResolver = ContextUtils.getApplicationContext().getContentResolver();
+        mQueryUri = Uri.withAppendedPath(baseUri, "authorized");
+        mRequestUri = Uri.withAppendedPath(baseUri, "requested");
+        mSupportsRequest = mContentResolver.getType(mRequestUri) != null;
+    }
+
+    /**
+     * Simple helper method to expose the constructor over JNI.
+     */
+    @CalledByNative
+    private static ContentResolverWebRestrictionProvider create(String authority) {
+        return new ContentResolverWebRestrictionProvider(authority);
+    }
+
+    /**
+     * @return whether the web restriction provider supports requesting access for a blocked url.
+     */
+    @CalledByNative
+    private boolean supportsRequest() {
+        return mSupportsRequest;
+    }
+
+    /**
+     * Whether we can proceed with loading the {@code url}.
+     * In case the url is not to be loaded, the web restriction provider can return an optional
+     * error page to show instead.
+     */
+    @CalledByNative
+    private void shouldProceed(final long nativeCallback, final String url) {
+        String select = String.format("url = '%s'", url);
+        Cursor result = mContentResolver.query(mQueryUri, null, select, null, null);
+        boolean shouldProceed = result == null || result.getInt(0) > 0;
+        String errorPage = shouldProceed ? null : result.getString(1);
+        nativeShouldProceed(nativeCallback, shouldProceed, errorPage);
+    }
+
+    /**
+     * Request permission to load the {@code url}.
+     * The web restriction provider returns a {@code boolean} variable indicating whether it was
+     * able to forward the request to the appropriate authority who can approve it.
+     */
+    @CalledByNative
+    private void requestPermission(final long nativeCallback, final String url) {
+        // TODO(knn): register for updates
+        ContentValues values = new ContentValues(1);
+        values.put("url", url);
+        boolean requestSuccess = mContentResolver.insert(mRequestUri, values) != null;
+        nativeRequestSuccess(nativeCallback, requestSuccess);
+    }
+
+    private native void nativeShouldProceed(
+            long nativeSelfDeletingCallback, boolean shouldProceed, String errorPage);
+
+    private native void nativeRequestSuccess(
+            long nativeSelfDeletingCallback, boolean requestSuccess);
+}