diff --git a/.gitignore b/.gitignore index dc8faa65..ba473737 100644 --- a/.gitignore +++ b/.gitignore @@ -58,3 +58,5 @@ cmake-build*/ # A place to store stuff and get it git ignored ignore/* + +.DS_Store diff --git a/ChangeLog.md b/ChangeLog.md index f9f9e351..c47a37dd 100644 --- a/ChangeLog.md +++ b/ChangeLog.md @@ -1,3 +1,12 @@ +# Changes in 1.2.2 + +* [thread-check.h](include/clap/ext/thread-check.h): expand the thread-doc to clarify and expand realtime +* [latency.h](include/clap/ext/latency.h): adjust latency extension requirements +* [undo.h](include/clap/ext/draft/undo.h): re-design the interface + * the plugin interfaces have been separated into 2 independent ones + * the plugin interfaces are optional + * simplification of the design + # Changes in 1.2.1 ## New draft extensions diff --git a/include/clap/events.h b/include/clap/events.h index a6e97513..198c7222 100644 --- a/include/clap/events.h +++ b/include/clap/events.h @@ -297,11 +297,27 @@ typedef struct clap_event_midi { uint8_t data[3]; } clap_event_midi_t; +// clap_event_midi_sysex contains a pointer to a sysex contents buffer. +// The lifetime of this buffer is (from host->plugin) only the process +// call in which the event is delivered or (from plugin->host) only the +// duration of a try_push call. +// +// Since `clap_output_events.try_push` requires hosts to make a copy of +// an event, host implementers receiving sysex messages from plugins need +// to take care to both copy the event (so header, size, etc...) but +// also memcpy the contents of the sysex pointer to host-owned memory, and +// not just copy the data pointer. +// +// Similarly plugins retaining the sysex outside the lifetime of a single +// process call must copy the sysex buffer to plugin-owned memory. +// +// As a consequence, the data structure pointed to by the sysex buffer +// must be contiguous and copyable with `memcpy` of `size` bytes. typedef struct clap_event_midi_sysex { clap_event_header_t header; uint16_t port_index; - const uint8_t *buffer; // midi buffer + const uint8_t *buffer; // midi buffer. See lifetime comment above. uint32_t size; } clap_event_midi_sysex_t; diff --git a/include/clap/ext/draft/undo.h b/include/clap/ext/draft/undo.h index 365780e6..76070c38 100644 --- a/include/clap/ext/draft/undo.h +++ b/include/clap/ext/draft/undo.h @@ -1,8 +1,11 @@ #pragma once #include "../../plugin.h" +#include "../../stream.h" -static CLAP_CONSTEXPR const char CLAP_EXT_UNDO[] = "clap.undo/2"; +static CLAP_CONSTEXPR const char CLAP_EXT_UNDO[] = "clap.undo/4"; +static CLAP_CONSTEXPR const char CLAP_EXT_UNDO_CONTEXT[] = "clap.undo_context/4"; +static CLAP_CONSTEXPR const char CLAP_EXT_UNDO_DELTA[] = "clap.undo_delta/4"; #ifdef __cplusplus extern "C" { @@ -15,7 +18,7 @@ extern "C" { /// /// Calling host->undo() or host->redo() is equivalent to clicking undo/redo within the host's GUI. /// -/// If the plugin implements this interface then its undo and redo should be entirely delegated to +/// If the plugin uses this interface then its undo and redo should be entirely delegated to /// the host; clicking in the plugin's UI undo or redo is equivalent to clicking undo or redo in the /// host's UI. /// @@ -40,31 +43,32 @@ extern "C" { /// history. This simplifies the host implementation, leading to less bugs, a more robust design /// and maybe an easier experience for the user because there's a single undo context versus one /// for the host and one for each plugin instance. - -enum clap_undo_context_flags { - // While the host is within a change, it is impossible to perform undo or redo. - CLAP_UNDO_IS_WITHIN_CHANGE = 1 << 0, -}; - -enum clap_undo_delta_properties_flags { - // If not set, then all clap_undo_delta_properties's attributes become irrelevant. - // If set, then the plugin will provide deltas in host->change_made(). - CLAP_UNDO_DELTA_PROPERTIES_HAS_DELTA = 1 << 0, - - // If set, then the delta will be reusable in the future as long as the plugin is - // compatible with the given format_version. - CLAP_UNDO_DELTA_PROPERTIES_IS_PERSISTENT = 1 << 1, -}; +/// +/// This extension tries to make it as easy as possible for the plugin to hook into the host undo +/// and make it efficient when possible by using deltas. The plugin interfaces are all optional, and +/// the plugin can for a minimal implementation, just use the host interface and call +/// host->change_made() without providing a delta. This is enough for the host to know that it can +/// capture a plugin state for the undo step. typedef struct clap_undo_delta_properties { - // Bitmask of clap_undo_delta_properties_flags - uint64_t flags; + // If true, then the plugin will provide deltas in host->change_made(). + // If false, then all clap_undo_delta_properties's attributes become irrelevant. + bool has_delta; + + // If true, then the deltas can be stored on disk and re-used in the future as long as the plugin + // is compatible with the given format_version. + // + // If false, then format_version must be set to CLAP_INVALID_ID. + bool are_deltas_persistent; - // This represents the delta format version that the plugin is using. - uint32_t format_version; + // This represents the delta format version that the plugin is currently using. + // Use CLAP_INVALID_ID for invalid value. + clap_id format_version; } clap_undo_delta_properties_t; -typedef struct clap_plugin_undo { +// Use CLAP_EXT_UNDO_DELTA. +// This is an optional interface, using deltas is an optimization versus making a state snapshot. +typedef struct clap_plugin_undo_delta { // Asks the plugin the delta properties. // [main-thread] void(CLAP_ABI *get_delta_properties)(const clap_plugin_t *plugin, @@ -76,25 +80,42 @@ typedef struct clap_plugin_undo { bool(CLAP_ABI *can_use_delta_format_version)(const clap_plugin_t *plugin, clap_id format_version); - // Applies synchronously a delta. + // Undo using the delta. // Returns true on success. // // [main-thread] - bool(CLAP_ABI *apply_delta)(const clap_plugin_t *plugin, - clap_id format_version, - const void *delta, - size_t delta_size); - - // Sets the undo context. - // flags: bitmask of clap_undo_context_flags values - // names: null terminated string if an redo/undo step exists, null otherwise. - // [main-thread] - void(CLAP_ABI *set_context_info)(const clap_plugin_t *plugin, - uint64_t flags, - const char *undo_name, - const char *redo_name); -} clap_plugin_undo_t; + bool(CLAP_ABI *undo)(const clap_plugin_t *plugin, + clap_id format_version, + const void *delta, + size_t delta_size); + // Redo using the delta. + // Returns true on success. + // + // [main-thread] + bool(CLAP_ABI *redo)(const clap_plugin_t *plugin, + clap_id format_version, + const void *delta, + size_t delta_size); +} clap_plugin_undo_delta_t; + +// Use CLAP_EXT_UNDO_CONTEXT. +// This is an optional interface, that the plugin can implement in order to know about +// the current undo context. +typedef struct clap_plugin_undo_context { + // Indicate if it is currently possible to perform an undo or redo operation. + // [main-thread & plugin-subscribed-to-undo-context] + void(CLAP_ABI *set_can_undo)(const clap_plugin_t *plugin, bool can_undo); + void(CLAP_ABI *set_can_redo)(const clap_plugin_t *plugin, bool can_redo); + + // Sets the name of the next undo or redo step. + // name: null terminated string. + // [main-thread & plugin-subscribed-to-undo-context] + void(CLAP_ABI *set_undo_name)(const clap_plugin_t *plugin, const char *name); + void(CLAP_ABI *set_redo_name)(const clap_plugin_t *plugin, const char *name); +} clap_plugin_undo_context_t; + +// Use CLAP_EXT_UNDO. typedef struct clap_host_undo { // Begins a long running change. // The plugin must not call this twice: there must be either a call to cancel_change() or @@ -112,36 +133,51 @@ typedef struct clap_host_undo { // // name: mandatory null terminated string describing the change, this is displayed to the user // - // deltas: optional, they are binary blobs used to perform the undo and redo. When not available + // delta: optional, it is a binary blobs used to perform the undo and redo. When not available // the host will save the plugin state and use state->load() to perform undo and redo. + // The plugin must be able to perform a redo operation using the delta, though the undo operation + // is only possible if delta_can_undo is true. // // Note: the provided delta may be used for incremental state saving and crash recovery. The // plugin can indicate a format version id and the validity lifetime for the binary blobs. // The host can use these to verify the compatibility before applying the delta. // If the plugin is unable to use a delta, a notification should be provided to the user and - // the crash recovery should perform a best effort job, at least restoring the latest saved state. + // the crash recovery should perform a best effort job, at least restoring the latest saved + // state. // // Special case: for objects with shared and synchronized state, changes shouldn't be reported // as the host already knows about it. // For example, plugin parameter changes shouldn't produce a call to change_made(). // + // Note: if the plugin asked for this interface, then host_state->mark_dirty() will not create an + // implicit undo step. + // + // Note: if the plugin did load a preset or did something that leads to a large delta, + // it may consider not producing a delta (pass null) and let the host make a state snapshot + // instead. + // + // Note: if a plugin is producing a lot of changes within a small amount of time, the host + // may merge them into a single undo step. + // // [main-thread] void(CLAP_ABI *change_made)(const clap_host_t *host, const char *name, - const void *redo_delta, - size_t redo_delta_size, - const void *undo_delta, - size_t undo_delta_size); - - // Asks the host to perform the next undo step. - // This operation may be asynchronous. - // [main-thread] - void(CLAP_ABI *undo)(const clap_host_t *host); + const void *delta, + size_t delta_size, + bool delta_can_undo); - // Asks the host to perform the next redo step. - // This operation may be asynchronous. + // Asks the host to perform the next undo or redo step. + // + // Note: this maybe a complex and asynchronous operation, which may complete after + // this function returns. + // + // Note: the host may ignore this request if there is no undo/redo step to perform, + // or if the host is unable to perform undo/redo at the time (eg: a long running + // change is going on). + // // [main-thread] - void(CLAP_ABI *redo)(const clap_host_t *host); + void(CLAP_ABI *request_undo)(const clap_host_t *host); + void(CLAP_ABI *request_redo)(const clap_host_t *host); // Subscribes to or unsubscribes from undo context info. // @@ -154,8 +190,10 @@ typedef struct clap_host_undo { // // is_subscribed: set to true to receive context info // + // It is mandatory for the plugin to implement CLAP_EXT_UNDO_CONTEXT when using this method. + // // [main-thread] - void(CLAP_ABI *set_context_info_subscription)(const clap_host_t *host, bool is_subscribed); + void(CLAP_ABI *set_wants_context_updates)(const clap_host_t *host, bool is_subscribed); } clap_host_undo_t; #ifdef __cplusplus diff --git a/include/clap/ext/latency.h b/include/clap/ext/latency.h index 6c9df1b1..d10a1326 100644 --- a/include/clap/ext/latency.h +++ b/include/clap/ext/latency.h @@ -10,15 +10,15 @@ extern "C" { typedef struct clap_plugin_latency { // Returns the plugin latency in samples. - // [main-thread & active] + // [main-thread & (being-activated | active)] uint32_t(CLAP_ABI *get)(const clap_plugin_t *plugin); } clap_plugin_latency_t; typedef struct clap_host_latency { // Tell the host that the latency changed. - // The latency is only allowed to change if the plugin is deactivated. + // The latency is only allowed to change during plugin->activate. // If the plugin is activated, call host->request_restart() - // [main-thread] + // [main-thread & being-activated] void(CLAP_ABI *changed)(const clap_host_t *host); } clap_host_latency_t; diff --git a/include/clap/ext/thread-check.h b/include/clap/ext/thread-check.h index 7b68e1b0..493e192d 100644 --- a/include/clap/ext/thread-check.h +++ b/include/clap/ext/thread-check.h @@ -17,23 +17,44 @@ extern "C" { /// This will be the same OS thread throughout the lifetime of the plug-in. /// On macOS and Windows, this must be the thread on which gui and timer events are received /// (i.e., the main thread of the program). -/// It isn't a realtime thread, yet this thread needs to respond fast enough to user interaction, -/// so it is recommended to run long and expensive tasks such as preset indexing or asset loading -/// in dedicated background threads. +/// It isn't a realtime thread, yet this thread needs to respond fast enough to allow responsive +/// user interaction, so it is strongly recommended plugins run long,and expensive or blocking +/// tasks such as preset indexing or asset loading in dedicated background threads started by the +/// plugin. /// /// audio-thread: -/// This thread is used for realtime audio processing. Its execution should be as deterministic -/// as possible to meet the audio interface's deadline (can be <1ms). In other words, there is a -/// known set of operations that should be avoided: malloc() and free(), mutexes (spin mutexes -/// are worse), I/O, waiting, ... -/// The audio-thread is something symbolic, there isn't one OS thread that remains the -/// audio-thread for the plugin lifetime. As you may guess, the host is likely to have a +/// This thread can be used for realtime audio processing. Its execution should be as +/// deterministic as possible to meet the audio interface's deadline (can be <1ms). There are a +/// known set of operations that should be avoided: malloc() and free(), contended locks and +/// mutexes, I/O, waiting, and so forth. +/// +/// The audio-thread is symbolic, there isn't one OS thread that remains the +/// audio-thread for the plugin lifetime. A host is may opt to have a /// thread pool and the plugin.process() call may be scheduled on different OS threads over time. -/// The most important thing is that there can't be two audio-threads at the same time. All the -/// functions marked with [audio-thread] **ARE NOT CONCURRENT**. The host may mark any OS thread, +/// However, the host must guarantee that single plugin instance will not be two audio-threads +/// at the same time. +/// +/// Functions marked with [audio-thread] **ARE NOT CONCURRENT**. The host may mark any OS thread, /// including the main-thread as the audio-thread, as long as it can guarantee that only one OS -/// thread is the audio-thread at a time. The audio-thread can be seen as a concurrency guard for -/// all functions marked with [audio-thread]. +/// thread is the audio-thread at a time in a plugin instance. The audio-thread can be seen as a +/// concurrency guard for all functions marked with [audio-thread]. +/// +/// The real-time constraint on the [audio-thread] interacts closely with the render extension. +/// If a plugin doesn't implement render, then that plugin must have all [audio-thread] functions +/// meet the real time standard. If the plugin does implement render, and returns true when +/// render mode is set to real-time or if the plugin advertises a hard realtime requirement, it +/// must implement realtime constraints. Hosts also provide functions marked [audio-thread]. +/// These can be safely called by a plugin in the audio thread. Therefore hosts must either (1) +/// implement those functions meeting the real-time constraints or (2) not process plugins which +/// advertise a hard realtime constraint or don't implement the render extension. Hosts which +/// provide [audio-thread] functions outside these conditions may experience inconsistent or +/// inaccurate rendering. +/// +/// Clap also tags some functions as [thread-safe]. Functions tagged as [thread-safe] can be called +/// from any thread unless explicitly counter-indicated (for instance [thread-safe, !audio-thread]) +/// and may be called concurrently. Since a [thread-safe] function may be called from the +/// [audio-thread] unless explicitly counter-indicated, it must also meet the realtime constraints +/// as describes above. // This interface is useful to do runtime checks and make // sure that the functions are called on the correct threads. diff --git a/include/clap/host.h b/include/clap/host.h index ddfeb8e7..c647c198 100644 --- a/include/clap/host.h +++ b/include/clap/host.h @@ -35,6 +35,12 @@ typedef struct clap_host { void(CLAP_ABI *request_process)(const struct clap_host *host); // Request the host to schedule a call to plugin->on_main_thread(plugin) on the main thread. + // This callback should be called as soon as practicable, usually in the host application's next + // available main thread time slice. Typically callbacks occur withink 33ms / 30hz. + // Despite this guidance, plugins should not make assumptions about the exactness of timing for + // a main thread callback, but hosts should endeavour to be prompt. For example, in high load situations + // the environment may starve the gui/main thread in favor of audio processing, leading to substantially + // longer latencies for the callback than the indicative times given here. // [thread-safe] void(CLAP_ABI *request_callback)(const struct clap_host *host); } clap_host_t; diff --git a/include/clap/version.h b/include/clap/version.h index fdbd03a7..d11069c1 100644 --- a/include/clap/version.h +++ b/include/clap/version.h @@ -22,7 +22,7 @@ typedef struct clap_version { #define CLAP_VERSION_MAJOR 1 #define CLAP_VERSION_MINOR 2 -#define CLAP_VERSION_REVISION 1 +#define CLAP_VERSION_REVISION 2 #define CLAP_VERSION_INIT \ { (uint32_t)CLAP_VERSION_MAJOR, (uint32_t)CLAP_VERSION_MINOR, (uint32_t)CLAP_VERSION_REVISION }