chromium/src/third_party/blink/public/platform/web_callbacks.h

/*
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 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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#ifndef THIRD_PARTY_BLINK_PUBLIC_PLATFORM_WEB_CALLBACKS_H_
#define THIRD_PARTY_BLINK_PUBLIC_PLATFORM_WEB_CALLBACKS_H_

namespace blink {

// A WebCallbacks<S, T> represents a callback object. Typically it is created
// in Blink and passed to Chromium, and onSuccess or onError will be called
// from Chromium.
// When transferring ownership, use |std::unique_ptr<X>| as a type
// parameter. Otherwise, |const X&| or |X| for a type parameter. It is
// generally not preferred to use |X*| because the object ownership is not well
// specified.

template <typename S, typename T>
class WebCallbacks {
 public:
  virtual ~WebCallbacks() = default;
  virtual void OnSuccess(S) {}
  virtual void OnError(T) {}
};

template <typename S>
class WebCallbacks<S, void> {
 public:
  virtual ~WebCallbacks() = default;
  virtual void OnSuccess(S) {}
  virtual void OnError() {}
};

}  // namespace blink

#endif