1 files changed, 188 insertions, 0 deletions
diff --git a/js/xpconnect/src/XPCThrower.cpp b/js/xpconnect/src/XPCThrower.cpp
new file mode 100644
index 0000000000..bee0a0b0f5
--- /dev/null
+++ b/js/xpconnect/src/XPCThrower.cpp
@@ -0,0 +1,188 @@
+/* -*- 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/. */
+
+/* Code for throwing errors into JavaScript. */
+
+#include "xpcprivate.h"
+#include "XPCWrapper.h"
+#include "js/CharacterEncoding.h"
+#include "js/Printf.h"
+#include "mozilla/dom/BindingUtils.h"
+#include "mozilla/dom/DOMException.h"
+#include "mozilla/dom/Exceptions.h"
+#include "nsString.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+bool XPCThrower::sVerbose = true;
+
+// static
+void XPCThrower::Throw(nsresult rv, JSContext* cx) {
+  const char* format;
+  if (JS_IsExceptionPending(cx)) {
+    return;
+  }
+  if (!nsXPCException::NameAndFormatForNSResult(rv, nullptr, &format)) {
+    format = "";
+  }
+  dom::Throw(cx, rv, nsDependentCString(format));
+}
+
+namespace xpc {
+
+bool Throw(JSContext* cx, nsresult rv) {
+  XPCThrower::Throw(rv, cx);
+  return false;
+}
+
+}  // namespace xpc
+
+/*
+ * If there has already been an exception thrown, see if we're throwing the
+ * same sort of exception, and if we are, don't clobber the old one. ccx
+ * should be the current call context.
+ */
+// static
+bool XPCThrower::CheckForPendingException(nsresult result, JSContext* cx) {
+  RefPtr<Exception> e = XPCJSContext::Get()->GetPendingException();
+  if (!e) {
+    return false;
+  }
+  XPCJSContext::Get()->SetPendingException(nullptr);
+
+  if (e->GetResult() != result) {
+    return false;
+  }
+
+  ThrowExceptionObject(cx, e);
+  return true;
+}
+
+// static
+void XPCThrower::Throw(nsresult rv, XPCCallContext& ccx) {
+  char* sz;
+  const char* format;
+
+  if (CheckForPendingException(rv, ccx)) {
+    return;
+  }
+
+  if (!nsXPCException::NameAndFormatForNSResult(rv, nullptr, &format)) {
+    format = "";
+  }
+
+  sz = (char*)format;
+  NS_ENSURE_TRUE_VOID(sz);
+
+  if (sz && sVerbose) {
+    Verbosify(ccx, &sz, false);
+  }
+
+  dom::Throw(ccx, rv, nsDependentCString(sz));
+
+  if (sz && sz != format) {
+    js_free(sz);
+  }
+}
+
+// static
+void XPCThrower::ThrowBadResult(nsresult rv, nsresult result,
+                                XPCCallContext& ccx) {
+  char* sz;
+  const char* format;
+  const char* name;
+
+  /*
+   *  If there is a pending exception when the native call returns and
+   *  it has the same error result as returned by the native call, then
+   *  the native call may be passing through an error from a previous JS
+   *  call. So we'll just throw that exception into our JS.  Note that
+   *  we don't need to worry about NS_ERROR_UNCATCHABLE_EXCEPTION,
+   *  because presumably there would be no pending exception for that
+   *  nsresult!
+   */
+
+  if (CheckForPendingException(result, ccx)) {
+    return;
+  }
+
+  // else...
+
+  if (!nsXPCException::NameAndFormatForNSResult(rv, nullptr, &format) ||
+      !format) {
+    format = "";
+  }
+
+  if (nsXPCException::NameAndFormatForNSResult(result, &name, nullptr) &&
+      name) {
+    sz = JS_smprintf("%s 0x%x (%s)", format, (unsigned)result, name).release();
+  } else {
+    sz = JS_smprintf("%s 0x%x", format, (unsigned)result).release();
+  }
+  NS_ENSURE_TRUE_VOID(sz);
+
+  if (sz && sVerbose) {
+    Verbosify(ccx, &sz, true);
+  }
+
+  dom::Throw(ccx, result, nsDependentCString(sz));
+
+  if (sz) {
+    js_free(sz);
+  }
+}
+
+// static
+void XPCThrower::ThrowBadParam(nsresult rv, unsigned paramNum,
+                               XPCCallContext& ccx) {
+  char* sz;
+  const char* format;
+
+  if (!nsXPCException::NameAndFormatForNSResult(rv, nullptr, &format)) {
+    format = "";
+  }
+
+  sz = JS_smprintf("%s arg %d", format, paramNum).release();
+  NS_ENSURE_TRUE_VOID(sz);
+
+  if (sz && sVerbose) {
+    Verbosify(ccx, &sz, true);
+  }
+
+  dom::Throw(ccx, rv, nsDependentCString(sz));
+
+  if (sz) {
+    js_free(sz);
+  }
+}
+
+// static
+void XPCThrower::Verbosify(XPCCallContext& ccx, char** psz, bool own) {
+  char* sz = nullptr;
+
+  if (ccx.HasInterfaceAndMember()) {
+    XPCNativeInterface* iface = ccx.GetInterface();
+    jsid id = ccx.GetMember()->GetName();
+    const char* name;
+    JS::UniqueChars bytes;
+    if (!id.isVoid()) {
+      bytes = JS_EncodeStringToLatin1(ccx, id.toString());
+      name = bytes ? bytes.get() : "";
+    } else {
+      name = "Unknown";
+    }
+    sz =
+        JS_smprintf("%s [%s.%s]", *psz, iface->GetNameString(), name).release();
+  }
+
+  if (sz) {
+    if (own) {
+      js_free(*psz);
+    }
+    *psz = sz;
+  }
+}