| #ifndef QUICHE_HTTP2_ADAPTER_WINDOW_MANAGER_H_ |
| #define QUICHE_HTTP2_ADAPTER_WINDOW_MANAGER_H_ |
| |
| #include <functional> |
| |
| namespace http2 { |
| namespace adapter { |
| |
| // This class keeps track of a HTTP/2 flow control window, notifying a listener |
| // when a window update needs to be sent. This class is not thread-safe. |
| class WindowManager { |
| public: |
| // A WindowUpdateListener is invoked when it is time to send a window update. |
| typedef std::function<void(size_t)> WindowUpdateListener; |
| |
| WindowManager(size_t window_size_limit, |
| WindowUpdateListener listener); |
| |
| size_t CurrentWindowSize() const { return window_; } |
| size_t WindowSizeLimit() const { return limit_; } |
| |
| // Called when the window size limit is changed (typically via settings) but |
| // no window update should be sent. |
| void OnWindowSizeLimitChange(size_t new_limit); |
| |
| // Sets the window size limit to |new_limit| and notifies the listener to |
| // update as necessary. |
| void SetWindowSizeLimit(size_t new_limit); |
| |
| // Increments the running total of data bytes buffered. Returns true iff there |
| // is more window remaining. |
| bool MarkDataBuffered(size_t bytes); |
| |
| // Increments the running total of data bytes that have been flushed or |
| // dropped. Invokes the listener if the current window is smaller than some |
| // threshold and there is quota available to send. |
| void MarkDataFlushed(size_t bytes); |
| |
| // Convenience method, used when incoming data is immediately dropped or |
| // ignored. |
| void MarkWindowConsumed(size_t bytes) { |
| MarkDataBuffered(bytes); |
| MarkDataFlushed(bytes); |
| } |
| |
| private: |
| friend class WindowManagerPeer; |
| |
| void MaybeNotifyListener(); |
| |
| // The upper bound on the flow control window. The GFE attempts to maintain a |
| // window of this size at the peer as data is proxied through. |
| size_t limit_; |
| |
| // The current flow control window that has not been advertised to the peer |
| // and not yet consumed. The peer can send this many bytes before becoming |
| // blocked. |
| size_t window_; |
| |
| // The amount of data already buffered, which should count against the flow |
| // control window upper bound. |
| size_t buffered_; |
| |
| WindowUpdateListener listener_; |
| }; |
| |
| } // namespace adapter |
| } // namespace http2 |
| |
| #endif // QUICHE_HTTP2_ADAPTER_WINDOW_MANAGER_H_ |