4 #include <alsa/asoundlib.h>
10 #include <unordered_map>
13 #include "alsa_input.h"
14 #include "bmusb/bmusb.h"
18 class DeviceSpecProto;
20 // The class dealing with the collective of all ALSA cards in the system.
21 // In particular, it deals with enumeration of cards, and hotplug of new ones.
29 // There is no card here. (There probably used to be one,
30 // but it got removed.) We don't insert a card before
31 // we've actually probed it, ie., we know whether it
32 // can be captured from at all, and what its name is.
35 // This card is ready for capture, as far as we know.
36 // (It could still be used by someone else; we don't know
37 // until we try to open it.)
40 // We are trying to start capture from this card, but we are not
41 // streaming yet. Note that this could in theory go on forever,
42 // if the card is in use by some other process; in the UI,
43 // we will show this state as “(busy)”.
46 // The card is capturing and sending data. If there's a fatal error,
47 // it could go back to STARTING, or it could go to DEAD
48 // (depending on the error).
51 // The card is gone (e.g., unplugged). However, since there's
52 // still a bus using it, we can't just remove the entry.
53 // If the card comes back (ie., a new card is plugged in,
54 // and we believe it has the same configuration), it could be
55 // installed in place of this card, and then presumably be put
56 // back into STARTING or RUNNING.
58 } state = State::EMPTY;
60 std::string address; // E.g. “hw:0,0”.
61 std::string name, info;
62 unsigned num_channels;
63 ALSAInput *input = nullptr; // nullptr iff EMPTY or DEAD.
65 // Whether the AudioMixer is interested in this card or not.
66 // “Interested” could mean either of two things: Either it is part of
67 // a bus mapping, or it is in the process of enumerating devices
68 // (to show to the user). A card that is _not_ held can disappear
69 // at any given time as a result of an error or hotplug event;
70 // a card that is held will go to the DEAD state instead.
73 std::string display_name() const { return name + " (" + info + ")"; }
78 // Get the list of all current devices. Note that this will implicitly mark
79 // all of the returned devices as held, since the input mapping UI needs
80 // some kind of stability when the user is to choose. Thus, when you are done
81 // with the list and have set a new mapping, you must go through all the devices
82 // you don't want and release them using release_device().
83 std::vector<Device> get_devices();
85 void hold_device(unsigned index);
86 void release_device(unsigned index); // Note: index is allowed to go out of bounds.
88 // If device is held, start or restart capture. If device is not held,
89 // stop capture if it isn't already.
90 void reset_device(unsigned index);
92 // Note: The card must be held. Returns OUTPUT_FREQUENCY if the card is in EMPTY or DEAD.
93 unsigned get_capture_frequency(unsigned index);
95 // Note: The card must be held.
96 Device::State get_card_state(unsigned index);
98 // Only for ALSAInput.
99 void set_card_state(unsigned index, Device::State state);
101 // Just a short form for taking <mu> and then moving the card to
102 // EMPTY or DEAD state. Only for ALSAInput and for internal use.
103 void free_card(unsigned index);
105 // Create a new card, mark it immediately as DEAD and hold it.
106 // Returns the new index.
107 unsigned create_dead_card(const std::string &name, const std::string &info, unsigned num_channels);
109 // Make a protobuf representation of the given card, so that it can be
110 // matched against at a later stage. For AudioMixer only.
111 // The given card must be held.
112 void serialize_device(unsigned index, DeviceSpecProto *serialized);
115 mutable std::mutex mu;
116 std::vector<Device> devices; // Under mu.
117 std::vector<std::unique_ptr<ALSAInput>> inputs; // Under mu, corresponds 1:1 to devices.
119 // Keyed on device address (e.g. “hw:0,0”). If there's an entry here,
120 // it means we already have a thread doing retries, so we shouldn't
122 std::unordered_map<std::string, unsigned> add_device_tries_left; // Under add_device_mutex.
123 std::mutex add_device_mutex;
125 static constexpr int num_retries = 10;
127 void inotify_thread_func();
128 void enumerate_devices();
130 // Try to add an input at the given card/device. If it succeeds, return
131 // synchronously. If not, fire off a background thread to try up to
132 // <num_retries> times.
133 void probe_device_with_retry(unsigned card_index, unsigned dev_index);
134 void probe_device_retry_thread_func(unsigned card_index, unsigned dev_index);
136 enum class ProbeResult {
141 ProbeResult probe_device_once(unsigned card_index, unsigned dev_index);
143 void unplug_device(unsigned card_index, unsigned dev_index);
145 // Must be called with <mu> held. Will allocate a new entry if needed.
146 // The returned entry will be set to READY state.
147 unsigned find_free_device_index(const std::string &name,
148 const std::string &info,
149 unsigned num_channels,
150 const std::string &address);
152 std::atomic<bool> should_quit{false};
154 std::thread inotify_thread;
155 std::atomic<int> retry_threads_running{0};
157 friend class ALSAInput;
160 #endif // !defined(_ALSA_POOL_H)