android: wire up on trailers (#514)

Description: this PR wires up on trailers callback for android, which was previously missing. Risk Level: low - using already battled tested code paths for accumulating headers. Testing: pending testing with gRPC on the Lyft android app Fixes #506 Signed-off-by: Jose Nino <[email protected]> Signed-off-by: JP Simard <[email protected]>
envoyproxy · Nov 29, 2022 · 0b57e34 · 0b57e34
1 parent d8a854b
commit 0b57e34
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diff --git a/mobile/library/common/jni_interface.cc b/mobile/library/common/jni_interface.cc
@@ -172,7 +172,18 @@ static void jvm_on_metadata(envoy_headers metadata, void* context) {
 
 static void jvm_on_trailers(envoy_headers trailers, void* context) {
   __android_log_write(ANDROID_LOG_ERROR, "jni_lib", "jvm_on_trailers");
-  __android_log_write(ANDROID_LOG_ERROR, "jni_lib", std::to_string(trailers.length).c_str());
+
+  JNIEnv* env = get_env();
+  jobject j_context = static_cast<jobject>(context);
+
+  jclass jcls_JvmCallbackContext = env->GetObjectClass(j_context);
+  jmethodID jmid_onTrailers = env->GetMethodID(jcls_JvmCallbackContext, "onTrailers", "(J)V");
+  // Note: be careful of JVM types
+  // FIXME: make this cast safer
+  env->CallVoidMethod(j_context, jmid_onTrailers, (jlong)trailers.length);
+
+  env->DeleteLocalRef(jcls_JvmCallbackContext);
+  pass_headers(env, trailers, j_context);
 }
 
 static void jvm_on_error(envoy_error error, void* context) {

diff --git a/mobile/library/java/src/io/envoyproxy/envoymobile/engine/JvmCallbackContext.java b/mobile/library/java/src/io/envoyproxy/envoymobile/engine/JvmCallbackContext.java
@@ -42,6 +42,14 @@ public void onHeaders(long length, boolean endStream) {
     startAccumulation(FrameType.HEADERS, length, endStream);
   }
 
+  /**
+   * Initializes state for accumulating trailer pairs via passHeaders, ultimately
+   * to be dispatched via the callback.
+   *
+   * @param length, the total number of trailers included in this header block.
+   */
+  public void onTrailers(long length) { startAccumulation(FrameType.TRAILERS, length, true); }
+
   /**
    * Allows pairs of strings to be passed across the JVM, reducing overall calls
    * (at the expense of some complexity).