56 lines
1.8 KiB
C
56 lines
1.8 KiB
C
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// gKeyMapper daemon - watches the mappings file for changes (inotify).
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#ifndef GKEYMAPPER_DAEMON_CONFIG_WATCH_H
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#define GKEYMAPPER_DAEMON_CONFIG_WATCH_H
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#include <string>
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namespace gkeymapper::daemon {
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// Watches mappings.conf so a save in the GUI is picked up without a signal.
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//
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// The *directory* is watched, not the file: that also catches an atomic save
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// (write a temporary file, rename it over the config) and the config appearing
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// after it was deleted.
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//
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// poll_events() collects whatever happened since the last call and take_change()
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// reports it once. Because the daemon evaluates this once per loop iteration
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// (at least every read timeout, i.e. 500 ms), all events a single save produces
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// collapse into one reload, and the file is complete by the time it is read
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// (that is what the atomic save in shared/mapping.cpp guarantees).
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//
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// The daemon still accepts SIGHUP/SIGUSR1 as a fallback when inotify is
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// unavailable.
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class ConfigWatcher {
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public:
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ConfigWatcher() = default;
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~ConfigWatcher();
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ConfigWatcher(const ConfigWatcher&) = delete;
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ConfigWatcher& operator=(const ConfigWatcher&) = delete;
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// Watches the directory holding `path` (creating it if it does not exist
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// yet). Returns false if inotify cannot be set up; the daemon then relies
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// on signals only.
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bool init(const std::string& path);
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bool is_watching() const { return fd_ >= 0; }
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// Consumes queued inotify events. Non-blocking and cheap; call it once per
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// event-loop iteration.
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void poll_events();
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// True if the mappings file changed since the last call; clears the mark so
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// every change is reported exactly once.
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bool take_change();
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private:
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int fd_ = -1;
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std::string directory_;
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std::string name_;
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bool pending_ = false;
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};
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} // namespace gkeymapper::daemon
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#endif // GKEYMAPPER_DAEMON_CONFIG_WATCH_H
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