Move control of the in-VM context lifecycle to the host specific code. (proxy-wasm#17)

* Move control of the in-VM context lifecycle to the host specific code.

Signed-off-by: John Plevyak <[email protected]>

Author: jplevyak

WORKSPACE

@@ -5,7 +5,7 @@ load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
 
 git_repository(
     name = "proxy_wasm_cpp_sdk",
-    commit = "b273b07ae0cfa9cc76dfe38236b163e9e3a2ab49",
+    commit = "f750d1f5da6a2f20cc55da75dd9772b7ba1650ca",
     remote = "https://github.com/proxy-wasm/proxy-wasm-cpp-sdk",
 )
 

include/proxy-wasm/null_plugin.h

@@ -42,7 +42,7 @@ template <typename T> using Optional = optional<T>;
 struct NullPluginRegistry {
   uint32_t (*proxy_validate_configuration_)(uint32_t root_context_id,
                                             uint32_t plugin_configuration_size) = nullptr;
-  uint32_t (*proxy_on_context_create_)(uint32_t context_id, uint32_t parent_context_id) = nullptr;
+  void (*proxy_on_context_create_)(uint32_t context_id, uint32_t parent_context_id) = nullptr;
   uint32_t (*proxy_on_vm_start_)(uint32_t root_context_id,
                                  uint32_t vm_configuration_size) = nullptr;
   uint32_t (*proxy_on_configure_)(uint32_t root_context_id,

src/context.cc

@@ -251,6 +251,7 @@ bool ContextBase::onStart(std::shared_ptr<PluginBase> plugin) {
   if (wasm_->on_context_create_) {
     plugin_ = plugin;
     wasm_->on_context_create_(this, id_, 0);
+    in_vm_context_created_ = true;
     plugin_.reset();
   }
   if (wasm_->on_vm_start_) {
@@ -277,10 +278,14 @@ bool ContextBase::onConfigure(std::shared_ptr<PluginBase> plugin) {
 }
 
 void ContextBase::onCreate(uint32_t parent_context_id) {
-  if (wasm_->on_context_create_) {
+  if (!in_vm_context_created_ && wasm_->on_context_create_) {
     DeferAfterCallActions actions(this);
     wasm_->on_context_create_(this, id_, parent_context_id);
+    in_vm_context_created_ = true;
   }
+  // NB: If no on_context_create function is registered the in-VM SDK is responsible for
+  // managing any required in-VM state.
+  in_vm_context_created_ = true;
 }
 
 // Shared Data
@@ -337,11 +342,10 @@ void ContextBase::onTick(uint32_t) {
 }
 
 FilterStatus ContextBase::onNetworkNewConnection() {
-  DeferAfterCallActions actions(this);
-  onCreate(root_context_id_);
   if (!wasm_->on_new_connection_) {
     return FilterStatus::Continue;
   }
+  DeferAfterCallActions actions(this);
   if (wasm_->on_new_connection_(this, id_).u64_ == 0) {
     return FilterStatus::Continue;
   }
@@ -388,12 +392,10 @@ void ContextBase::onUpstreamConnectionClose(CloseType close_type) {
 template <typename P> static uint32_t headerSize(const P &p) { return p ? p->size() : 0; }
 
 FilterHeadersStatus ContextBase::onRequestHeaders(uint32_t headers, bool end_of_stream) {
-  DeferAfterCallActions actions(this);
-  onCreate(root_context_id_);
-  in_vm_context_created_ = true;
   if (!wasm_->on_request_headers_) {
     return FilterHeadersStatus::Continue;
   }
+  DeferAfterCallActions actions(this);
   auto result =
       wasm_->on_request_headers_(this, id_, headers, static_cast<uint32_t>(end_of_stream)).u64_;
   if (result > static_cast<uint64_t>(FilterHeadersStatus::StopAllIterationAndWatermark))
@@ -438,18 +440,10 @@ FilterMetadataStatus ContextBase::onRequestMetadata(uint32_t elements) {
 }
 
 FilterHeadersStatus ContextBase::onResponseHeaders(uint32_t headers, bool end_of_stream) {
-  DeferAfterCallActions actions(this);
-  if (!in_vm_context_created_) {
-    // If the request is invalid then onRequestHeaders() will not be called and neither will
-    // onCreate() then sendLocalReply be called which will call this function. In this case we
-    // need to call onCreate() so that the Context inside the VM is created before the
-    // onResponseHeaders() call.
-    onCreate(root_context_id_);
-    in_vm_context_created_ = true;
-  }
   if (!wasm_->on_response_headers_) {
     return FilterHeadersStatus::Continue;
   }
+  DeferAfterCallActions actions(this);
   auto result =
       wasm_->on_response_headers_(this, id_, headers, static_cast<uint32_t>(end_of_stream)).u64_;
   if (result > static_cast<uint64_t>(FilterHeadersStatus::StopAllIterationAndWatermark))
@@ -542,23 +536,23 @@ void ContextBase::onGrpcClose(uint32_t token, uint32_t status_code) {
 }
 
 bool ContextBase::onDone() {
-  DeferAfterCallActions actions(this);
   if (wasm_->on_done_) {
+    DeferAfterCallActions actions(this);
     return wasm_->on_done_(this, id_).u64_ != 0;
   }
   return true;
 }
 
 void ContextBase::onLog() {
-  DeferAfterCallActions actions(this);
   if (wasm_->on_log_) {
+    DeferAfterCallActions actions(this);
     wasm_->on_log_(this, id_);
   }
 }
 
 void ContextBase::onDelete() {
-  DeferAfterCallActions actions(this);
-  if (wasm_->on_delete_) {
+  if (in_vm_context_created_ && wasm_->on_delete_) {
+    DeferAfterCallActions actions(this);
     wasm_->on_delete_(this, id_);
   }
 }