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