Add support for setting allow http flag in Dart VM (flutter#17653)

Author: mehmetf

common/settings.h

@@ -99,6 +99,10 @@ struct Settings {
   bool endless_trace_buffer = false;
   bool enable_dart_profiling = false;
   bool disable_dart_asserts = false;
+
+  // Used to signal the embedder whether HTTP connections are disabled.
+  bool disable_http = false;
+
   // Used as the script URI in debug messages. Does not affect how the Dart code
   // is executed.
   std::string advisory_script_uri = "main.dart";

lib/io/BUILD.gn

@@ -9,6 +9,7 @@ source_set("io") {
   ]
 
   deps = [
+    "//flutter/fml",
     "//flutter/third_party/tonic",
     "//third_party/dart/runtime:dart_api",
     "//third_party/dart/runtime/bin:dart_io_api",

lib/io/dart_io.cc

@@ -4,21 +4,31 @@
 
 #include "flutter/lib/io/dart_io.h"
 
+#include "flutter/fml/logging.h"
+
 #include "third_party/dart/runtime/include/bin/dart_io_api.h"
 #include "third_party/dart/runtime/include/dart_api.h"
 #include "third_party/tonic/converter/dart_converter.h"
+#include "third_party/tonic/logging/dart_error.h"
 
+using tonic::LogIfError;
 using tonic::ToDart;
 
 namespace flutter {
 
-void DartIO::InitForIsolate() {
+void DartIO::InitForIsolate(bool disable_http) {
   Dart_Handle result = Dart_SetNativeResolver(
       Dart_LookupLibrary(ToDart("dart:io")), dart::bin::LookupIONative,
       dart::bin::LookupIONativeSymbol);
-  if (Dart_IsError(result)) {
-    Dart_PropagateError(result);
-  }
+  FML_CHECK(!LogIfError(result));
+
+  // The SDK expects this field to represent "allow http" so we switch the
+  // value.
+  Dart_Handle allow_http_value = disable_http ? Dart_False() : Dart_True();
+  Dart_Handle set_field_result =
+      Dart_SetField(Dart_LookupLibrary(ToDart("dart:_http")),
+                    ToDart("_embedderAllowsHttp"), allow_http_value);
+  FML_CHECK(!LogIfError(set_field_result));
 }
 
 }  // namespace flutter

lib/io/dart_io.h

@@ -13,7 +13,7 @@ namespace flutter {
 
 class DartIO {
  public:
-  static void InitForIsolate();
+  static void InitForIsolate(bool disable_http);
 
  private:
   FML_DISALLOW_IMPLICIT_CONSTRUCTORS(DartIO);

runtime/dart_isolate.cc

@@ -137,7 +137,8 @@ DartIsolate::DartIsolate(const Settings& settings,
                   settings.log_tag,
                   settings.unhandled_exception_callback,
                   DartVMRef::GetIsolateNameServer()),
-      is_root_isolate_(is_root_isolate) {
+      is_root_isolate_(is_root_isolate),
+      disable_http_(settings.disable_http) {
   phase_ = Phase::Uninitialized;
 }
 
@@ -261,7 +262,7 @@ bool DartIsolate::LoadLibraries() {
 
   tonic::DartState::Scope scope(this);
 
-  DartIO::InitForIsolate();
+  DartIO::InitForIsolate(disable_http_);
 
   DartUI::InitForIsolate(IsRootIsolate());
 

runtime/dart_isolate.h

@@ -402,6 +402,7 @@ class DartIsolate : public UIDartState {
   std::vector<std::unique_ptr<AutoFireClosure>> shutdown_callbacks_;
   fml::RefPtr<fml::TaskRunner> message_handling_task_runner_;
   const bool is_root_isolate_;
+  const bool disable_http_;
 
   DartIsolate(const Settings& settings,
               TaskRunners task_runners,

shell/common/switches.cc

@@ -237,6 +237,9 @@ Settings SettingsFromCommandLine(const fml::CommandLine& command_line) {
     }
   }
 
+  settings.disable_http =
+      command_line.HasOption(FlagForSwitch(Switch::DisableHttp));
+
   // Disable need for authentication codes for VM service communication, if
   // specified.
   settings.disable_service_auth_codes =

shell/common/switches.h

@@ -174,6 +174,12 @@ DEF_SWITCH(DisableDartAsserts,
            "disabled. This flag may be specified if the user wishes to run "
            "with assertions disabled in the debug product mode (i.e. with JIT "
            "or DBC).")
+DEF_SWITCH(DisableHttp,
+           "disable-http",
+           "Dart VM has a master switch that can be set to disable insecure "
+           "HTTP and WebSocket protocols. Localhost or loopback addresses are "
+           "exempted. This flag can be specified if the embedder wants this "
+           "for a particular platform.")
 DEF_SWITCH(
     ForceMultithreading,
     "force-multithreading",