Expose CSSLayoutSetLogger to java

Summary: Expose CSSLayoutSetLogger to java

Reviewed By: astreet

Differential Revision: D4153502

fbshipit-source-id: 630909d9d0d36d94d7cd3027476ddb52668b8cc0

java/com/facebook/csslayout/CSSLogger.java

@@ -0,0 +1,27 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+package com.facebook.csslayout;
+
+import com.facebook.proguard.annotations.DoNotStrip;
+
+/**
+ * Inteface for recieving logs from native layer. Use by setting CSSNode.setLogger(myLogger);
+ * LOG_LEVEL_ERROR indicated a fatal error.
+ */
+public interface CSSLogger {
+  public final int LOG_LEVEL_ERROR = 0;
+  public final int LOG_LEVEL_WARN = 1;
+  public final int LOG_LEVEL_INFO = 2;
+  public final int LOG_LEVEL_DEBUG = 3;
+  public final int LOG_LEVEL_VERBOSE = 4;
+
+  @DoNotStrip
+  void log(int level, String message);
+}

java/com/facebook/csslayout/CSSNode.java

@@ -33,6 +33,12 @@ public class CSSNode implements CSSNodeAPI<CSSNode> {
    * Get native instance count. Useful for testing only.
    */
   static native int jni_CSSNodeGetInstanceCount();
+  static native void jni_CSSLog(int level, String message);
+
+  private static native void jni_CSSLayoutSetLogger(Object logger);
+  public static void setLogger(CSSLogger logger) {
+    jni_CSSLayoutSetLogger(logger);
+  }
 
   private CSSNode mParent;
   private List<CSSNode> mChildren;

java/jni/CSSJNI.cpp

@@ -68,10 +68,43 @@ static CSSSize _jniMeasureFunc(CSSNodeRef node,
   return CSSSize{measuredWidth, measuredHeight};
 }
 
+static global_ref<jobject> *jLogger;
+static int _jniLog(CSSLogLevel level, const char *format, va_list args) {
+  char buffer[256];
+  int result = vsnprintf(buffer, sizeof(buffer), format, args);
+
+  static auto logFunc =
+      findClassLocal("com/facebook/csslayout/CSSLogger")->getMethod<void(jint, jstring)>("log");
+  logFunc(jLogger->get(), static_cast<jint>(level), Environment::current()->NewStringUTF(buffer));
+
+  return result;
+}
+
 static inline CSSNodeRef _jlong2CSSNodeRef(jlong addr) {
   return reinterpret_cast<CSSNodeRef>(static_cast<intptr_t>(addr));
 }
 
+void jni_CSSLayoutSetLogger(alias_ref<jclass> clazz, alias_ref<jobject> logger) {
+  if (jLogger) {
+    jLogger->releaseAlias();
+    delete jLogger;
+  }
+
+  if (logger) {
+    jLogger = new global_ref<jobject>(make_global(logger));
+    CSSLayoutSetLogger(_jniLog);
+  } else {
+    jLogger = NULL;
+    CSSLayoutSetLogger(NULL);
+  }
+}
+
+void jni_CSSLog(alias_ref<jclass> clazz, jint level, jstring message) {
+  const char *nMessage = Environment::current()->GetStringUTFChars(message, 0);
+  CSSLog(static_cast<CSSLogLevel>(level), "%s", nMessage);
+  Environment::current()->ReleaseStringUTFChars(message, nMessage);
+}
+
 jint jni_CSSNodeGetInstanceCount(alias_ref<jclass> clazz) {
   return CSSNodeGetInstanceCount();
 }
@@ -256,6 +289,8 @@ jint JNI_OnLoad(JavaVM *vm, void *) {
                         CSSMakeNativeMethod(jni_CSSNodeStyleSetMaxHeight),
 
                         CSSMakeNativeMethod(jni_CSSNodeGetInstanceCount),
+                        CSSMakeNativeMethod(jni_CSSLayoutSetLogger),
+                        CSSMakeNativeMethod(jni_CSSLog),
                     });
   });
 }

java/tests/com/facebook/csslayout/CSSNodeTest.java

@@ -39,4 +39,36 @@ public class CSSNodeTest {
     assertEquals(100, (int) node.getLayoutWidth());
     assertEquals(100, (int) node.getLayoutHeight());
   }
+
+  private int mLogLevel;
+  private String mLogMessage;
+
+  @Test
+  public void testLogger() {
+    CSSNode.setLogger(new CSSLogger() {
+        public void log(int level, String message) {
+          mLogLevel = level;
+          mLogMessage = message;
+        }
+    });
+    CSSNode.jni_CSSLog(CSSLogger.LOG_LEVEL_DEBUG, "Hello");
+    assertEquals(CSSLogger.LOG_LEVEL_DEBUG, mLogLevel);
+    assertEquals("Hello", mLogMessage);
+  }
+
+  @Test
+  public void testUpdateLogger() {
+    CSSNode.setLogger(new CSSLogger() {
+        public void log(int level, String message) {}
+    });
+    CSSNode.setLogger(new CSSLogger() {
+        public void log(int level, String message) {
+          mLogLevel = level;
+          mLogMessage = message;
+        }
+    });
+    CSSNode.jni_CSSLog(CSSLogger.LOG_LEVEL_VERBOSE, "Flexbox");
+    assertEquals(CSSLogger.LOG_LEVEL_VERBOSE, mLogLevel);
+    assertEquals("Flexbox", mLogMessage);
+  }
 }