src/developer/feedback_agent/scenic_ptr.cc

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.

#include "src/developer/feedback_agent/scenic_ptr.h"

#include <lib/async/cpp/task.h>
#include <lib/syslog/cpp/logger.h>
#include <zircon/errors.h>
#include <zircon/status.h>

namespace fuchsia {
namespace feedback {

Scenic::Scenic(async_dispatcher_t* dispatcher, std::shared_ptr<::sys::ServiceDirectory> services)
    : dispatcher_(dispatcher), services_(services) {}

fit::promise<fuchsia::ui::scenic::ScreenshotData> Scenic::TakeScreenshot(
    const zx::duration timeout) {
  scenic_ = services_->Connect<fuchsia::ui::scenic::Scenic>();

  // fit::promise does not have the notion of a timeout. So we post a delayed task that will call
  // the completer after the timeout and return an error.
  //
  // We wrap the delayed task in a CancelableClosure so we can cancel it when the fit::bridge is
  // completed another way.
  //
  // It is safe to pass "this" to the fit::function as the callback won't be callable when the
  // CancelableClosure goes out of scope, which is before "this".
  done_after_timeout_.Reset([this] {
    if (!done_.completer) {
      return;
    }

    FX_LOGS(ERROR) << "Screenshot take timed out";
    done_.completer.complete_error();
  });
  const zx_status_t post_status = async::PostDelayedTask(
      dispatcher_, [cb = done_after_timeout_.callback()] { cb(); }, timeout);
  if (post_status != ZX_OK) {
    FX_PLOGS(ERROR, post_status) << "Failed to post delayed task";
    FX_LOGS(ERROR) << "Skipping screenshot take as it is not safe without a timeout";
    return fit::make_result_promise<fuchsia::ui::scenic::ScreenshotData>(fit::error());
  }

  scenic_.set_error_handler([this](zx_status_t status) {
    if (!done_.completer) {
      return;
    }

    FX_PLOGS(ERROR, status) << "Lost connection to fuchsia.ui.scenic.Scenic";
    done_.completer.complete_error();
  });

  scenic_->TakeScreenshot([this](fuchsia::ui::scenic::ScreenshotData raw_screenshot, bool success) {
    if (!done_.completer) {
      return;
    }

    if (!success) {
      FX_LOGS(ERROR) << "Scenic failed to take screenshot";
      done_.completer.complete_error();
    } else {
      done_.completer.complete_ok(std::move(raw_screenshot));
    }
  });

  return done_.consumer.promise_or(fit::error())
      .then([this](fit::result<fuchsia::ui::scenic::ScreenshotData>& result) {
        done_after_timeout_.Cancel();
        return std::move(result);
      });
}

}  // namespace feedback
}  // namespace fuchsia