Add lint rule to find incorrect alias files

This helps catch errors like
http://code.google.com/p/android/issues/detail?id=36821

Change-Id: I1ceda3183d8b1e29510ba0be2523dc6eb9c7a23b

3 files changed, 113 insertions, 1 deletions

diff --git a/lint/libs/lint_checks/src/com/android/tools/lint/checks/BuiltinIssueRegistry.java b/lint/libs/lint_checks/src/com/android/tools/lint/checks/BuiltinIssueRegistry.java
index 8e4ab9d..3c08e82 100644
--- a/lint/libs/lint_checks/src/com/android/tools/lint/checks/BuiltinIssueRegistry.java
+++ b/lint/libs/lint_checks/src/com/android/tools/lint/checks/BuiltinIssueRegistry.java
@@ -54,7 +54,7 @@ public class BuiltinIssueRegistry extends IssueRegistry {
     private static final List<Issue> sIssues;
 
     static {
-        final int initialCapacity = 104;
+        final int initialCapacity = 105;
         List<Issue> issues = new ArrayList<Issue>(initialCapacity);
 
         issues.add(AccessibilityDetector.ISSUE);
@@ -145,6 +145,7 @@ public class BuiltinIssueRegistry extends IssueRegistry {
         issues.add(TypoDetector.ISSUE);
         issues.add(ViewTypeDetector.ISSUE);
         issues.add(WrongImportDetector.ISSUE);
+        issues.add(WrongLocationDetector.ISSUE);
         issues.add(ViewConstructorDetector.ISSUE);
         issues.add(NamespaceDetector.CUSTOMVIEW);
         issues.add(NamespaceDetector.UNUSED);
diff --git a/lint/libs/lint_checks/src/com/android/tools/lint/checks/WrongLocationDetector.java b/lint/libs/lint_checks/src/com/android/tools/lint/checks/WrongLocationDetector.java
new file mode 100644
index 0000000..8a19e20
--- /dev/null
+++ b/lint/libs/lint_checks/src/com/android/tools/lint/checks/WrongLocationDetector.java
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.tools.lint.checks;
+
+import static com.android.tools.lint.detector.api.LintConstants.TAG_RESOURCES;
+
+import com.android.annotations.NonNull;
+import com.android.tools.lint.detector.api.Category;
+import com.android.tools.lint.detector.api.Issue;
+import com.android.tools.lint.detector.api.LayoutDetector;
+import com.android.tools.lint.detector.api.Scope;
+import com.android.tools.lint.detector.api.Severity;
+import com.android.tools.lint.detector.api.Speed;
+import com.android.tools.lint.detector.api.XmlContext;
+
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+
+/** Looks for problems with XML files being placed in the wrong folder */
+public class WrongLocationDetector extends LayoutDetector {
+    /** Main issue investigated by this detector */
+    public static final Issue ISSUE = Issue.create(
+            "WrongFolder", //$NON-NLS-1$
+
+            "Finds resource files that are placed in the wrong folders",
+
+            "Resource files are sometimes placed in the wrong folder, and it can lead to " +
+            "subtle bugs that are hard to understand. This check looks for problems in this " +
+            "area, such as attempting to place a layout \"alias\" file in a `layout/` folder " +
+            "rather than the `values/` folder where it belongs.",
+            Category.CORRECTNESS,
+            8,
+            Severity.ERROR,
+            WrongLocationDetector.class,
+            Scope.RESOURCE_FILE_SCOPE);
+
+    /** Constructs a new {@link WrongLocationDetector} check */
+    public WrongLocationDetector() {
+    }
+
+    @Override
+    public @NonNull Speed getSpeed() {
+        return Speed.FAST;
+    }
+
+    @Override
+    public void visitDocument(@NonNull XmlContext context, @NonNull Document document) {
+        Element root = document.getDocumentElement();
+        if (root != null && root.getTagName().equals(TAG_RESOURCES)) {
+            context.report(ISSUE, context.getLocation(root),
+                    "This file should be placed in a values/ folder, not a layout/ folder", null);
+        }
+    }
+}
diff --git a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/WrongLocationDetectorTest.java b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/WrongLocationDetectorTest.java
new file mode 100644
index 0000000..f30a604
--- /dev/null
+++ b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/WrongLocationDetectorTest.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.tools.lint.checks;
+
+import com.android.tools.lint.detector.api.Detector;
+
+@SuppressWarnings("javadoc")
+public class WrongLocationDetectorTest extends AbstractCheckTest {
+    @Override
+    protected Detector getDetector() {
+        return new WrongLocationDetector();
+    }
+
+    public void test() throws Exception {
+        assertEquals(
+            "res/layout/alias.xml:17: Error: This file should be placed in a values/ folder, not a layout/ folder [WrongFolder]\n" +
+            "<resources>\n" +
+            "^\n" +
+            "1 errors, 0 warnings\n",
+
+        lintProject("res/values/strings.xml=>res/layout/alias.xml"));
+    }
+
+    public void testOk() throws Exception {
+        assertEquals("No warnings.",
+
+        lintProject("res/values/strings.xml"));
+    }
+}