/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: sw=2 ts=8 et :
 */
/* 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/. */

#include "X11Util.h"
#include "nsDebug.h"          // for NS_ASSERTION, etc
#include "MainThreadUtils.h"  // for NS_IsMainThread

namespace mozilla {

void FindVisualAndDepth(Display* aDisplay, VisualID aVisualID, Visual** aVisual,
                        int* aDepth) {
  const Screen* screen = DefaultScreenOfDisplay(aDisplay);

  for (int d = 0; d < screen->ndepths; d++) {
    Depth* d_info = &screen->depths[d];
    for (int v = 0; v < d_info->nvisuals; v++) {
      Visual* visual = &d_info->visuals[v];
      if (visual->visualid == aVisualID) {
        *aVisual = visual;
        *aDepth = d_info->depth;
        return;
      }
    }
  }

  NS_ASSERTION(aVisualID == X11None, "VisualID not on Screen.");
  *aVisual = nullptr;
  *aDepth = 0;
}

void FinishX(Display* aDisplay) {
  unsigned long lastRequest = NextRequest(aDisplay) - 1;
  if (lastRequest == LastKnownRequestProcessed(aDisplay)) return;

  XSync(aDisplay, False);
}

ScopedXErrorHandler::ErrorEvent* ScopedXErrorHandler::sXErrorPtr;

int ScopedXErrorHandler::ErrorHandler(Display*, XErrorEvent* ev) {
  // only record the error if no error was previously recorded.
  // this means that in case of multiple errors, it's the first error that we
  // report.
  if (!sXErrorPtr->mError.error_code) sXErrorPtr->mError = *ev;
  return 0;
}

ScopedXErrorHandler::ScopedXErrorHandler(bool aAllowOffMainThread) {
  if (!aAllowOffMainThread) {
    // Off main thread usage is not safe in general, but OMTC GL layers uses
    // this with the main thread blocked, which makes it safe.
    NS_WARNING_ASSERTION(
        NS_IsMainThread(),
        "ScopedXErrorHandler being called off main thread, may cause issues");
  }
  // let sXErrorPtr point to this object's mXError object, but don't reset this
  // mXError object! think of the case of nested ScopedXErrorHandler's.
  mOldXErrorPtr = sXErrorPtr;
  sXErrorPtr = &mXError;
  mOldErrorHandler = XSetErrorHandler(ErrorHandler);
}

ScopedXErrorHandler::~ScopedXErrorHandler() {
  sXErrorPtr = mOldXErrorPtr;
  XSetErrorHandler(mOldErrorHandler);
}

bool ScopedXErrorHandler::SyncAndGetError(Display* dpy, XErrorEvent* ev) {
  FinishX(dpy);

  bool retval = mXError.mError.error_code != 0;
  if (ev) *ev = mXError.mError;
  mXError = ErrorEvent();  // reset
  return retval;
}

}  // namespace mozilla