void start_capture_thread();
void stop_capture_thread();
- // TODO: Worry about hotplug.
- struct Device {
- std::string address; // E.g. “hw:0,0”.
- std::string name, info;
- unsigned num_channels;
- };
- static std::vector<Device> enumerate_devices();
-
private:
void capture_thread_func();
int64_t frames_to_pts(uint64_t n) const;
void die_on_error(const char *func_name, int err);
- static bool set_base_params(const char *device, snd_pcm_t *pcm_handle, snd_pcm_hw_params_t *hw_params, unsigned *sample_rate);
std::string device;
unsigned sample_rate, num_channels, num_periods;
std::unique_ptr<uint8_t[]> buffer;
};
+// The class dealing with the collective of all ALSA cards in the system.
+// In particular, it deals with enumeration of cards, and hotplug of new ones.
+class ALSAPool {
+public:
+ ~ALSAPool();
+
+ struct Device {
+ enum class State {
+ // There is no card here. (There probably used to be one,
+ // but it got removed.) We don't insert a card before
+ // we've actually probed it, ie., we know whether it
+ // can be captured from at all, and what its name is.
+ EMPTY,
+
+ // This card is ready for capture, as far as we know.
+ // (It could still be used by someone else; we don't know
+ // until we try to open it.)
+ READY,
+
+ // We are trying to start capture from this card, but we are not
+ // streaming yet. Note that this could in theory go on forever,
+ // if the card is in use by some other process; in the UI,
+ // we will show this state as “(busy)”.
+ STARTING,
+
+ // The card is capturing and sending data. If there's a fatal error,
+ // it could go back to STARTING, or it could go to DEAD
+ // (depending on the error).
+ RUNNING,
+
+ // The card is gone (e.g., unplugged). However, since there's
+ // still a bus using it, we can't just remove the entry.
+ // If the card comes back (ie., a new card is plugged in,
+ // and we believe it has the same configuration), it could be
+ // installed in place of this card, and then presumably be put
+ // back into STARTING or RUNNING.
+ DEAD
+ } state;
+
+ std::string address; // E.g. “hw:0,0”.
+ std::string name, info;
+ unsigned num_channels;
+ ALSAInput *input = nullptr; // nullptr iff EMPTY or DEAD.
+
+ // Whether the AudioMixer is interested in this card or not.
+ // “Interested” could mean either of two things: Either it is part of
+ // a bus mapping, or it is in the process of enumerating devices
+ // (to show to the user). A card that is _not_ held can disappear
+ // at any given time as a result of an error or hotplug event;
+ // a card that is held will go to the DEAD state instead.
+ bool held = false;
+ };
+
+ void init();
+
+ // Get the list of all current devices. Note that this will implicitly mark
+ // all of the returned devices as held, since the input mapping UI needs
+ // some kind of stability when the user is to choose. Thus, when you are done
+ // with the list and have set a new mapping, you must go through all the devices
+ // you don't want and release them using release_device().
+ std::vector<Device> get_devices();
+
+ void hold_device(unsigned index);
+ void release_device(unsigned index); // Note: index is allowed to go out of bounds.
+
+ // If device is held, start or restart capture. If device is not held,
+ // stop capture if it isn't already.
+ void reset_device(unsigned index);
+
+ // Note: The card must be held. Returns OUTPUT_FREQUENCY if the card is in EMPTY or DEAD.
+ unsigned get_capture_frequency(unsigned index);
+
+ // TODO: Add accessors and/or callbacks about changed state, so that
+ // the UI actually stands a chance in using that information.
+
+private:
+ mutable std::mutex mu;
+ std::vector<Device> devices; // Under mu.
+ std::vector<std::unique_ptr<ALSAInput>> inputs; // Under mu, corresponds 1:1 to devices.
+
+ void enumerate_devices();
+ bool add_device(unsigned card_index, unsigned dev_index);
+};
+
#endif // !defined(_ALSA_INPUT_H)
projects / nageru / blobdiff