53653: Eclipse: 100% CPU usage in ADT pattern matching code

Change-Id: I8ffcbecd6db644e9a199bd38da1df2aa12cae0a5

2 files changed, 43 insertions, 19 deletions

diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/Hyperlinks.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/Hyperlinks.java
index 91c4049..1df2e4d 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/Hyperlinks.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/Hyperlinks.java
@@ -162,7 +162,6 @@ import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.regex.Pattern;
 
 /**
  * Class containing hyperlink resolvers for XML and Java files to jump to associated
@@ -184,10 +183,36 @@ public class Hyperlinks {
         // for the various inner classes that are actual hyperlink resolvers.
     }
 
-    /** Regular expression matching a FQCN for a view class */
+    /**
+     * Returns whether a string represents a valid fully qualified name for a view class.
+     * Does not check for existence.
+     */
     @VisibleForTesting
-    /* package */ static final Pattern CLASS_PATTERN = Pattern.compile(
-        "(([a-zA-Z_\\$][a-zA-Z0-9_\\$]*)+\\.)+[a-zA-Z_\\$][a-zA-Z0-9_\\$]*"); //$NON-NLS-1$
+    static boolean isViewClassName(String name) {
+        int length = name.length();
+        if (length < 2 || name.indexOf('.') == -1) {
+            return false;
+        }
+
+        boolean lastWasDot = true;
+        for (int i = 0; i < length; i++) {
+            char c = name.charAt(i);
+            if (lastWasDot) {
+                if (!Character.isJavaIdentifierStart(c)) {
+                    return false;
+                }
+                lastWasDot = false;
+            } else {
+                if (c == '.') {
+                    lastWasDot = true;
+                } else if (!Character.isJavaIdentifierPart(c)) {
+                    return false;
+                }
+            }
+        }
+
+        return !lastWasDot;
+    }
 
     /** Determines whether the given attribute <b>name</b> is linkable */
     private static boolean isAttributeNameLink(XmlContext context) {
@@ -368,7 +393,7 @@ public class Hyperlinks {
         // If the element looks like a fully qualified class name (e.g. it's a custom view
         // element) offer it as a link
         String tag = context.getElement().getTagName();
-        return (tag.indexOf('.') != -1 && CLASS_PATTERN.matcher(tag).matches());
+        return isViewClassName(tag);
     }
 
     /** Returns the FQCN for a class declaration at the given context */
diff --git a/eclipse/plugins/com.android.ide.eclipse.tests/src/com/android/ide/eclipse/adt/internal/editors/HyperlinksTest.java b/eclipse/plugins/com.android.ide.eclipse.tests/src/com/android/ide/eclipse/adt/internal/editors/HyperlinksTest.java
index cb83947..20aae84 100644
--- a/eclipse/plugins/com.android.ide.eclipse.tests/src/com/android/ide/eclipse/adt/internal/editors/HyperlinksTest.java
+++ b/eclipse/plugins/com.android.ide.eclipse.tests/src/com/android/ide/eclipse/adt/internal/editors/HyperlinksTest.java
@@ -54,23 +54,22 @@ public class HyperlinksTest extends AdtProjectTest {
     }
 
     public void testFqnRegexp() throws Exception {
-        assertTrue(Hyperlinks.CLASS_PATTERN.matcher("com.android.Foo").matches());
-        assertTrue(Hyperlinks.CLASS_PATTERN.matcher("com.android.pk_g.Foo_Bar1").
-                matches());
-        assertTrue(Hyperlinks.CLASS_PATTERN.matcher("com.android.Foo$Inner").matches());
+        assertTrue(Hyperlinks.isViewClassName("com.android.Foo"));
+        assertTrue(Hyperlinks.isViewClassName("com.android.pk_g.Foo_Bar1"));
+        assertTrue(Hyperlinks.isViewClassName("com.android.Foo$Inner"));
 
         // Should we allow non-standard packages and class names?
         // For now, we're allowing it -- see how this works out in practice.
-        //assertFalse(XmlHyperlinkResolver.CLASS_PATTERN.matcher("Foo.bar").matches());
-        assertTrue(Hyperlinks.CLASS_PATTERN.matcher("Foo.bar").matches());
-
-        assertFalse(Hyperlinks.CLASS_PATTERN.matcher("LinearLayout").matches());
-        assertFalse(Hyperlinks.CLASS_PATTERN.matcher(".").matches());
-        assertFalse(Hyperlinks.CLASS_PATTERN.matcher(".F").matches());
-        assertFalse(Hyperlinks.CLASS_PATTERN.matcher("f.").matches());
-        assertFalse(Hyperlinks.CLASS_PATTERN.matcher("Foo").matches());
-        assertFalse(Hyperlinks.CLASS_PATTERN.matcher("com.android.1Foo").matches());
-        assertFalse(Hyperlinks.CLASS_PATTERN.matcher("1com.Foo").matches());
+        //assertFalse(XmlHyperlinkResolver.isViewClassName("Foo.bar"));
+        assertTrue(Hyperlinks.isViewClassName("Foo.bar"));
+
+        assertFalse(Hyperlinks.isViewClassName("LinearLayout"));
+        assertFalse(Hyperlinks.isViewClassName("."));
+        assertFalse(Hyperlinks.isViewClassName(".F"));
+        assertFalse(Hyperlinks.isViewClassName("f."));
+        assertFalse(Hyperlinks.isViewClassName("Foo"));
+        assertFalse(Hyperlinks.isViewClassName("com.android.1Foo"));
+        assertFalse(Hyperlinks.isViewClassName("1com.Foo"));
     }
 
     public void testNavigate1() throws Exception {