Issue #1442 - Part 2: Add a run-time preference for toggling the streams API. https://bugzilla.mozilla.org/show_bug.cgi?id=1272697

dom/workers/RuntimeService.cpp

@@ -299,6 +299,7 @@ LoadContextOptions(const char* aPrefName, void* /* aClosure */)
                 .setNativeRegExp(GetWorkerPref<bool>(NS_LITERAL_CSTRING("native_regexp")))
                 .setAsyncStack(GetWorkerPref<bool>(NS_LITERAL_CSTRING("asyncstack")))
                 .setWerror(GetWorkerPref<bool>(NS_LITERAL_CSTRING("werror")))
+                .setStreams(GetWorkerPref<bool>(NS_LITERAL_CSTRING("streams")))
                 .setExtraWarnings(GetWorkerPref<bool>(NS_LITERAL_CSTRING("strict")))
                 .setArrayProtoValues(GetWorkerPref<bool>(
                       NS_LITERAL_CSTRING("array_prototype_values")));

js/src/jsapi.h

@@ -1161,6 +1161,16 @@ class JS_PUBLIC_API(ContextOptions) {
         return *this;
     }
 
+    bool streams() const { return streams_; }
+    ContextOptions& setStreams(bool flag) {
+        streams_ = flag;
+        return *this;
+    }
+    ContextOptions& toggleStreams() {
+        streams_ = !streams_;
+        return *this;
+    }
+
     bool nativeRegExp() const { return nativeRegExp_; }
     ContextOptions& setNativeRegExp(bool flag) {
         nativeRegExp_ = flag;
@@ -1243,6 +1253,7 @@ class JS_PUBLIC_API(ContextOptions) {
     bool strictMode_ : 1;
     bool extraWarnings_ : 1;
     bool arrayProtoValues_ : 1;
+    bool streams_ : 1;
 };
 
 JS_PUBLIC_API(ContextOptions&)

js/src/shell/js.cpp

@@ -318,6 +318,7 @@ static bool enableUnboxedArrays = false;
 static bool enableSharedMemory = SHARED_MEMORY_DEFAULT;
 static bool enableWasmAlwaysBaseline = false;
 static bool enableArrayProtoValues = true;
+static bool enableStreams = false;
 static bool printTiming = false;
 static const char* jsCacheDir = nullptr;
 static const char* jsCacheAsmJSPath = nullptr;
@@ -7565,6 +7566,7 @@ SetContextOptions(JSContext* cx, const OptionParser& op)
     enableUnboxedArrays = op.getBoolOption("unboxed-arrays");
     enableWasmAlwaysBaseline = op.getBoolOption("wasm-always-baseline");
     enableArrayProtoValues = !op.getBoolOption("no-array-proto-values");
+    enableStreams = op.getBoolOption("enable-streams");
 
     JS::ContextOptionsRef(cx).setBaseline(enableBaseline)
                              .setIon(enableIon)
@@ -7573,7 +7575,8 @@ SetContextOptions(JSContext* cx, const OptionParser& op)
                              .setWasmAlwaysBaseline(enableWasmAlwaysBaseline)
                              .setNativeRegExp(enableNativeRegExp)
                              .setUnboxedArrays(enableUnboxedArrays)
-                             .setArrayProtoValues(enableArrayProtoValues);
+                             .setArrayProtoValues(enableArrayProtoValues)
+                             .setStreams(enableStreams);
 
     if (op.getBoolOption("wasm-check-bce"))
         jit::JitOptions.wasmAlwaysCheckBounds = true;
@@ -7845,7 +7848,8 @@ SetWorkerContextOptions(JSContext* cx)
                              .setWasmAlwaysBaseline(enableWasmAlwaysBaseline)
                              .setNativeRegExp(enableNativeRegExp)
                              .setUnboxedArrays(enableUnboxedArrays)
-                             .setArrayProtoValues(enableArrayProtoValues);
+                             .setArrayProtoValues(enableArrayProtoValues)
+                             .setStreams(enableStreams);
     cx->setOffthreadIonCompilationEnabled(offthreadCompilation);
     cx->profilingScripts = enableCodeCoverage || enableDisassemblyDumps;
 
@@ -8019,6 +8023,7 @@ main(int argc, char** argv, char** envp)
         || !op.addBoolOption('\0', "wasm-always-baseline", "Enable wasm baseline compiler when possible")
         || !op.addBoolOption('\0', "wasm-check-bce", "Always generate wasm bounds check, even redundant ones.")
         || !op.addBoolOption('\0', "no-array-proto-values", "Remove Array.prototype.values")
+        || !op.addBoolOption('\0', "enable-streams", "Enable WHATWG Streams")
 #ifdef ENABLE_SHARED_ARRAY_BUFFER
         || !op.addStringOption('\0', "shared-memory", "on/off",
                                "SharedArrayBuffer and Atomics "

js/xpconnect/src/XPCJSContext.cpp

@@ -1439,6 +1439,8 @@ ReloadPrefsCallback(const char* pref, void* data)
 
     bool extraWarnings = Preferences::GetBool(JS_OPTIONS_DOT_STR "strict");
     
+    bool streams = Preferences::GetBool(JS_OPTIONS_DOT_STR "streams");
+
     bool unboxedObjects = Preferences::GetBool(JS_OPTIONS_DOT_STR "unboxed_objects");
     
     bool inlining = Preferences::GetBool(JS_OPTIONS_DOT_STR "ion.inlining");
@@ -1463,7 +1465,8 @@ ReloadPrefsCallback(const char* pref, void* data)
                              .setDumpStackOnDebuggeeWouldRun(dumpStackOnDebuggeeWouldRun)
                              .setWerror(werror)
                              .setExtraWarnings(extraWarnings)
-                             .setArrayProtoValues(arrayProtoValues);
+                             .setArrayProtoValues(arrayProtoValues)
+                             .setStreams(streams);
 
     JS_SetParallelParsingEnabled(cx, parallelParsing);
     JS_SetOffthreadIonCompilationEnabled(cx, offthreadIonCompilation);

modules/libpref/init/all.js

@@ -1334,6 +1334,9 @@ pref("javascript.options.main_thread_stack_quota_cap", 2097152);
 // Dynamic module import.
 pref("javascript.options.dynamicImport", true);
 
+// Streams API
+pref("javascript.options.streams", false);
+
 // advanced prefs
 pref("advanced.mailftp",                    false);
 pref("image.animation_mode",                "normal");