From 4cbcb1c8f0842920eee5e153245d1b7e47553c0d Mon Sep 17 00:00:00 2001
From: Jan de Mooij <jdemooij@mozilla.com>
Date: Sat, 28 May 2016 13:11:17 +0200
Subject: [PATCH] Bug 1274922 part 2 - Give the shell its own
 EnvironmentPreparer. r=jorendorff

---
 js/src/shell/js.cpp | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/js/src/shell/js.cpp b/js/src/shell/js.cpp
index 54782aa36f82..be92680563ad 100644
--- a/js/src/shell/js.cpp
+++ b/js/src/shell/js.cpp
@@ -178,6 +178,16 @@ struct ShellRuntime
     bool quitting;
 };
 
+struct MOZ_STACK_CLASS EnvironmentPreparer : public js::ScriptEnvironmentPreparer {
+    JSContext* cx;
+    explicit EnvironmentPreparer(JSContext* cx)
+      : cx(cx)
+    {
+        js::SetScriptEnvironmentPreparer(JS_GetRuntime(cx), this);
+    }
+    void invoke(JS::HandleObject scope, Closure& closure) override;
+};
+
 // Shell state set once at startup.
 static bool enableCodeCoverage = false;
 static bool enableDisassemblyDumps = false;
@@ -496,6 +506,18 @@ SkipUTF8BOM(FILE* file)
         ungetc(ch1, file);
 }
 
+void
+EnvironmentPreparer::invoke(HandleObject scope, Closure& closure)
+{
+    MOZ_ASSERT(!JS_IsExceptionPending(cx));
+
+    AutoCompartment ac(cx, scope);
+    if (!closure(cx))
+        JS_ReportPendingException(cx);
+
+    MOZ_ASSERT(!JS_IsExceptionPending(cx));
+}
+
 static void
 RunFile(JSContext* cx, const char* filename, FILE* file, bool compileOnly)
 {
@@ -2952,6 +2974,8 @@ WorkerMain(void* arg)
     JS::SetEnqueuePromiseJobCallback(rt, ShellEnqueuePromiseJobCallback);
 #endif // SPIDERMONKEY_PROMISE
 
+    EnvironmentPreparer environmentPreparer(cx);
+
     JS::SetLargeAllocationFailureCallback(rt, my_LargeAllocFailCallback, (void*)cx);
 
     do {
@@ -7441,6 +7465,8 @@ main(int argc, char** argv, char** envp)
     JS::SetEnqueuePromiseJobCallback(rt, ShellEnqueuePromiseJobCallback);
 #endif // SPIDERMONKEY_PROMISE
 
+    EnvironmentPreparer environmentPreparer(cx);
+
     JS_SetGCParameter(rt, JSGC_MODE, JSGC_MODE_INCREMENTAL);
 
     JS::SetLargeAllocationFailureCallback(rt, my_LargeAllocFailCallback, (void*)cx);