1 files changed, 94 insertions, 0 deletions
diff --git a/js/src/debugger/NoExecute.h b/js/src/debugger/NoExecute.h
new file mode 100644
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+++ b/js/src/debugger/NoExecute.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef debugger_NoExecute_h
+#define debugger_NoExecute_h
+
+#include "mozilla/Assertions.h"  // for AssertionConditionType, MOZ_ASSERT
+#include "mozilla/Attributes.h"  // for MOZ_RAII
+
+#include "NamespaceImports.h"  // for HandleScript
+#include "js/Promise.h"        // for JS::AutoDebuggerJobQueueInterruption
+
+namespace js {
+
+class Debugger;
+class LeaveDebuggeeNoExecute;
+
+// Prevents all the debuggeee compartments of a given Debugger from executing
+// scripts. Attempts to run script will throw an
+// instance of Debugger.DebuggeeWouldRun from the topmost locked Debugger's
+// compartment.
+class MOZ_RAII EnterDebuggeeNoExecute {
+  friend class LeaveDebuggeeNoExecute;
+
+  Debugger& dbg_;
+  EnterDebuggeeNoExecute** stack_;
+  EnterDebuggeeNoExecute* prev_;
+
+  // Non-nullptr when unlocked temporarily by a LeaveDebuggeeNoExecute.
+  LeaveDebuggeeNoExecute* unlocked_;
+
+  // When DebuggeeWouldRun is a warning instead of an error, whether we've
+  // reported a warning already.
+  bool reported_;
+
+ public:
+  // Mark execution in dbg's debuggees as forbidden, for the lifetime of this
+  // object. Require an AutoDebuggerJobQueueInterruption in scope.
+  explicit EnterDebuggeeNoExecute(
+      JSContext* cx, Debugger& dbg,
+      const JS::AutoDebuggerJobQueueInterruption& adjqiProof);
+
+  ~EnterDebuggeeNoExecute() {
+    MOZ_ASSERT(*stack_ == this);
+    *stack_ = prev_;
+  }
+
+  Debugger& debugger() const { return dbg_; }
+
+#ifdef DEBUG
+  static bool isLockedInStack(JSContext* cx, Debugger& dbg);
+#endif
+
+  // Given a JSContext entered into a debuggee realm, find the lock
+  // that locks it. Returns nullptr if not found.
+  static EnterDebuggeeNoExecute* findInStack(JSContext* cx);
+
+  // Given a JSContext entered into a debuggee compartment, report a
+  // warning or an error if there is a lock that locks it.
+  static bool reportIfFoundInStack(JSContext* cx, HandleScript script);
+};
+
+// Given a JSContext entered into a debuggee compartment, if it is in
+// an NX section, unlock the topmost EnterDebuggeeNoExecute instance.
+//
+// Does nothing if debuggee is not in an NX section. For example, this
+// situation arises when invocation functions are called without entering
+// Debugger code, e.g., calling D.O.p.executeInGlobal or D.O.p.apply.
+class MOZ_RAII LeaveDebuggeeNoExecute {
+  EnterDebuggeeNoExecute* prevLocked_;
+
+ public:
+  explicit LeaveDebuggeeNoExecute(JSContext* cx)
+      : prevLocked_(EnterDebuggeeNoExecute::findInStack(cx)) {
+    if (prevLocked_) {
+      MOZ_ASSERT(!prevLocked_->unlocked_);
+      prevLocked_->unlocked_ = this;
+    }
+  }
+
+  ~LeaveDebuggeeNoExecute() {
+    if (prevLocked_) {
+      MOZ_ASSERT(prevLocked_->unlocked_ == this);
+      prevLocked_->unlocked_ = nullptr;
+    }
+  }
+};
+
+} /* namespace js */
+
+#endif /* debugger_NoExecute_h */