core: add native-platform callback implementation (#316)

Co-authored-by: Jose Ulises Nino Rivera <junr03@users.noreply.github.com>
Signed-off-by: Mike Schore <mike.schore@gmail.com>

library/common/buffer/utility.cc

@@ -10,7 +10,7 @@ namespace Utility {
 Buffer::InstancePtr transformData(envoy_data) { return nullptr; }
 
 // TODO: implement this https://github.com/lyft/envoy-mobile/issues/284.
-envoy_data transformData(Buffer::Instance&) { return {0, nullptr}; }
+envoy_data transformData(Buffer::Instance&) { return envoy_nodata; }
 
 } // namespace Utility
 } // namespace Buffer

library/common/http/dispatcher.cc

@@ -16,26 +16,26 @@ void Dispatcher::DirectStreamCallbacks::onHeaders(HeaderMapPtr&& headers, bool e
   if (end_stream) {
     http_dispatcher_.removeStream(stream_);
   }
-  observer_.on_headers_f(Utility::transformHeaders(*headers), end_stream, observer_.context);
+  observer_.on_headers(Utility::transformHeaders(*headers), end_stream, observer_.context);
 }
 
 void Dispatcher::DirectStreamCallbacks::onData(Buffer::Instance& data, bool end_stream) {
   ENVOY_LOG(debug, "response data for stream (length={} end_stream={})", data.length(), end_stream);
   if (end_stream) {
     http_dispatcher_.removeStream(stream_);
   }
-  observer_.on_data_f(Envoy::Buffer::Utility::transformData(data), end_stream, observer_.context);
+  observer_.on_data(Envoy::Buffer::Utility::transformData(data), end_stream, observer_.context);
 }
 
 void Dispatcher::DirectStreamCallbacks::onTrailers(HeaderMapPtr&& trailers) {
   ENVOY_LOG(debug, "response trailers for stream:\n{}", *trailers);
   http_dispatcher_.removeStream(stream_);
-  observer_.on_trailers_f(Utility::transformHeaders(*trailers), observer_.context);
+  observer_.on_trailers(Utility::transformHeaders(*trailers), observer_.context);
 }
 
 void Dispatcher::DirectStreamCallbacks::onReset() {
   http_dispatcher_.removeStream(stream_);
-  observer_.on_error_f({ENVOY_STREAM_RESET, {0, nullptr}}, observer_.context);
+  observer_.on_error({ENVOY_STREAM_RESET, envoy_nodata}, observer_.context);
 }
 
 Dispatcher::DirectStream::DirectStream(AsyncClient::Stream& underlying_stream,

library/common/http/header_utility.cc

@@ -9,7 +9,7 @@ namespace Utility {
 static inline envoy_data copyEnvoyData(size_t length, const uint8_t* source) {
   uint8_t* destination = static_cast<uint8_t*>(malloc(sizeof(uint8_t) * length));
   memcpy(destination, source, length);
-  return {length, destination};
+  return {length, destination, nullptr, nullptr};
 }
 
 std::string convertToString(envoy_data s) {
@@ -18,7 +18,7 @@ std::string convertToString(envoy_data s) {
 
 HeaderMapPtr transformHeaders(envoy_headers headers) {
   Http::HeaderMapPtr transformed_headers = std::make_unique<HeaderMapImpl>();
-  for (uint64_t i = 0; i < headers.length; i++) {
+  for (envoy_header_size_t i = 0; i < headers.length; i++) {
     transformed_headers->addCopy(LowerCaseString(convertToString(headers.headers[i].key)),
                                  convertToString(headers.headers[i].value));
   }

library/common/include/BUILD

@@ -6,6 +6,7 @@ envoy_package()
 
 envoy_cc_library(
     name = "c_types_interface",
+    srcs = ["c_types.cc"],
     hdrs = ["c_types.h"],
     repository = "@envoy",
 )

library/common/include/c_types.cc

@@ -0,0 +1,16 @@
+#include "library/common/include/c_types.h"
+
+// NOLINT(namespace-envoy)
+
+void envoy_noop_release(void* context) { (void)context; }
+
+void release_envoy_headers(envoy_headers headers) {
+  for (envoy_header_size_t i = 0; i < headers.length; i++) {
+    envoy_header header = headers.headers[i];
+    header.key.release(header.key.context);
+    header.value.release(header.value.context);
+  }
+  free(headers.headers);
+}
+
+const envoy_data envoy_nodata = {0, NULL, envoy_noop_release, NULL};

library/common/include/c_types.h

@@ -3,6 +3,7 @@
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
+#include <stdlib.h>
 
 // NOLINT(namespace-envoy)
 
@@ -28,12 +29,31 @@ typedef enum { ENVOY_SUCCESS, ENVOY_FAILURE } envoy_status_t;
  */
 typedef enum { ENVOY_STREAM_RESET } envoy_error_code_t;
 
+#ifdef __cplusplus
+extern "C" { // release function
+#endif
+/**
+ * Callback indicating Envoy has drained the associated buffer.
+ */
+typedef void (*envoy_release_f)(void* context);
+
+/**
+ * No-op callback.
+ */
+void envoy_noop_release(void* context);
+
+#ifdef __cplusplus
+} // release function
+#endif
+
 /**
  * Holds raw binary data as an array of bytes.
  */
 typedef struct {
-  uint64_t length;
+  size_t length;
   const uint8_t* bytes;
+  envoy_release_f release;
+  void* context;
 } envoy_data;
 
 /**
@@ -56,19 +76,29 @@ typedef struct {
   envoy_data value;
 } envoy_header;
 
+/**
+ * Consistent type for dealing with encodable/processable header counts.
+ */
+typedef int envoy_header_size_t;
+
 /**
  * Holds an HTTP header map as an array of envoy_header structs.
  */
 typedef struct {
   // Number of header elements in the array.
-  uint64_t length;
+  envoy_header_size_t length;
   // Array of headers.
   envoy_header* headers;
 } envoy_headers;
 
+/**
+ * Helper function to free/release memory associated with underlying headers.
+ */
+void release_envoy_headers(envoy_headers headers);
+
 // Convenience constant to pass to function calls with no data.
 // For example when sending a headers-only request.
-const envoy_data envoy_nodata = {0, NULL};
+extern const envoy_data envoy_nodata;
 
 /**
  * Error struct.
@@ -88,7 +118,7 @@ extern "C" { // function pointers
  * @param context, contains the necessary state to carry out platform-specific dispatch and
  * execution.
  */
-typedef void (*on_headers)(envoy_headers headers, bool end_stream, void* context);
+typedef void (*envoy_on_headers_f)(envoy_headers headers, bool end_stream, void* context);
 /**
  * Called when a data frame gets received on the async HTTP stream.
  * This callback can be invoked multiple times if the data gets streamed.
@@ -97,30 +127,33 @@ typedef void (*on_headers)(envoy_headers headers, bool end_stream, void* context
  * @param context, contains the necessary state to carry out platform-specific dispatch and
  * execution.
  */
-typedef void (*on_data)(envoy_data data, bool end_stream, void* context);
+typedef void (*envoy_on_data_f)(envoy_data data, bool end_stream, void* context);
 /**
- * Called when all metadata get received on the async HTTP stream.
- * Note that end stream is implied when on_metadata is called.
+ * Called when a metadata frame gets received on the async HTTP stream.
+ * Note that metadata frames are prohibited from ending a stream.
  * @param metadata, the metadata received.
  * @param context, contains the necessary state to carry out platform-specific dispatch and
  * execution.
  */
-typedef void (*on_metadata)(envoy_headers metadata, void* context);
+typedef void (*envoy_on_metadata_f)(envoy_headers metadata, void* context);
 /**
  * Called when all trailers get received on the async HTTP stream.
  * Note that end stream is implied when on_trailers is called.
  * @param trailers, the trailers received.
  * @param context, contains the necessary state to carry out platform-specific dispatch and
  * execution.
  */
-typedef void (*on_trailers)(envoy_headers trailers, void* context);
+typedef void (*envoy_on_trailers_f)(envoy_headers trailers, void* context);
 /**
  * Called when the async HTTP stream has an error.
  * @param envoy_error, the error received/caused by the async HTTP stream.
  * @param context, contains the necessary state to carry out platform-specific dispatch and
  * execution.
  */
-typedef void (*on_error)(envoy_error error, void* context);
+typedef void (*envoy_on_error_f)(envoy_error error, void* context);
+
+// FIXME comments
+typedef void (*envoy_on_complete_f)(void* context);
 
 #ifdef __cplusplus
 } // function pointers
@@ -130,10 +163,11 @@ typedef void (*on_error)(envoy_error error, void* context);
  * Interface that can handle HTTP callbacks.
  */
 typedef struct {
-  on_headers on_headers_f;
-  on_data on_data_f;
-  on_metadata on_metadata_f;
-  on_trailers on_trailers_f;
-  on_error on_error_f;
+  envoy_on_headers_f on_headers;
+  envoy_on_data_f on_data;
+  envoy_on_metadata_f on_metadata;
+  envoy_on_trailers_f on_trailers;
+  envoy_on_complete_f on_complete;
+  envoy_on_error_f on_error;
   void* context; // Will be passed through to callbacks to provide dispatch and execution state.
 } envoy_observer;

library/common/main_interface.cc

@@ -30,7 +30,7 @@ envoy_status_t send_headers(envoy_stream_t stream_id, envoy_headers headers, boo
 
 // TODO: implement.
 envoy_status_t send_data(envoy_stream_t, envoy_data, bool) { return ENVOY_FAILURE; }
-envoy_status_t send_metadata(envoy_stream_t, envoy_headers, bool) { return ENVOY_FAILURE; }
+envoy_status_t send_metadata(envoy_stream_t, envoy_headers) { return ENVOY_FAILURE; }
 envoy_status_t send_trailers(envoy_stream_t, envoy_headers) { return ENVOY_FAILURE; }
 envoy_status_t locally_close_stream(envoy_stream_t) { return ENVOY_FAILURE; }
 envoy_status_t reset_stream(envoy_stream_t) { return ENVOY_FAILURE; }

library/common/main_interface.h

@@ -41,10 +41,9 @@ envoy_status_t send_data(envoy_stream_t stream, envoy_data data, bool end_stream
  * Send metadata over an HTTP stream. This method can be invoked multiple times.
  * @param stream, the stream to send metadata over.
  * @param metadata, the metadata to send.
- * @param end_stream, supplies whether this is the last data in the stream.
  * @return envoy_status_t, the resulting status of the operation.
  */
-envoy_status_t send_metadata(envoy_stream_t stream, envoy_headers metadata, bool end_stream);
+envoy_status_t send_metadata(envoy_stream_t stream, envoy_headers metadata);
 
 /**
  * Send trailers over an open HTTP stream. This method can only be invoked once per stream.

library/objective-c/BUILD

@@ -2,18 +2,19 @@ licenses(["notice"])  # Apache 2
 
 exports_files([
     "EnvoyEngine.h",
-    "EnvoyTypes.h",
 ])
 
 objc_library(
     name = "envoy_engine_objc_lib",
+    # TODO(@goaway): The headers here should really be in hdrs, but this causes them to be imported
+    # twice due to the way they're pulled into our swift framework rule. We should fix this to
+    # maintain a valid objc target.
     srcs = [
-        "EnvoyEngine.mm",
+        "EnvoyEngine.m",
     ],
     hdrs = [
         "EnvoyEngine.h",
     ],
-    copts = ["-std=c++14"],
     visibility = ["//visibility:public"],
     deps = ["//library/common:envoy_main_interface_lib"],
 )