Merge branch 'next' into draft-includes

ChangeLog.md

@@ -14,6 +14,11 @@
 
 Note: we kept the last draft extension ID in order to not break plugins already using it.
 
+## Removed draft extensions
+
+* `CLAP_EXT_CHECK_FOR_UPDATE` wasn't used and it's design needed more thought.
+* `CLAP_EXT_MIDI_MAPPING` wasn't used. MIDI2 seems to do it better, and the interface wasn't satisfying.
+
 ## Stabilize factory
 * `CLAP_PRESET_DISCOVERY_FACTORY_ID`
 

README.md

@@ -11,7 +11,7 @@
   - [Extensions](#extensions)
   - [Fundamental extensions](#fundamental-extensions)
   - [Support extensions](#support-extensions)
-  - [Extra extensions](#extra-extensions)
+  - [Deeper Host integration](#deeper-host-integration)
   - [Third-party extensions](#third-party-extensions)
 - [Adapters](#adapters)
 - [Resources](#resources)
@@ -81,34 +81,45 @@ You can create your own extensions and share them. Make sure that the extension
 
 This is a list of the extensions that you most likely want to implement
 and use to get a basic plugin experience:
-- [log](include/clap/ext/log.h), lets the host aggregate plugin logs
-- [thread-check](include/clap/ext/thread-check.h), check which thread you are currently on, useful for correctness validation
-- [audio-ports](include/clap/ext/audio-ports.h), define the audio ports
-- [note-ports](include/clap/ext/note-ports.h), define the note ports
+- [state](include/clap/ext/state.h), save and load the plugin state
+  - [state-context](include/clap/ext/state-context.h), same as state but with additional context info (preset, duplicate, project)
+  - [resource-directory](include/clap/ext/draft/resource-directory.h), host provided folder for the plugin to save extra resource like multi-samples, ... (draft)
 - [params](include/clap/ext/params.h), parameters management
-- [latency](include/clap/ext/latency.h), report the plugin latency
+- [note-ports](include/clap/ext/note-ports.h), define the note ports
+- [audio-ports](include/clap/ext/audio-ports.h), define the audio ports
+  - [surround](include/clap/ext/surround.h), inspect surround channel mapping
+  - [ambisonic](include/clap/ext/draft/ambisonic.h), inspect ambisonic channel mapping (draft)
+  - [cv](include/clap/ext/draft/cv.h), inspect CV channel mapping (draft)
+  - [configurable-audio-ports](include/clap/ext/configurable-audio-ports.h), request the plugin to apply a given configuration
+  - [audio-ports-config](include/clap/ext/audio-ports-config.h), simple list of pre-defined audio ports configurations
+  - [audio-ports-activation](include/clap/ext/audio-ports-activation.h), activate and deactivate a given audio port
+  - [extensible-audio-ports](include/clap/ext/draft/extensible-audio-ports.h), let the host add audio ports to the plugin, this is useful for dynamic number of audio inputs (draft)
 - [render](include/clap/ext/render.h), renders realtime or offline
+- [latency](include/clap/ext/latency.h), report the plugin latency
 - [tail](include/clap/ext/tail.h), processing tail length
-- [state](include/clap/ext/state.h), save and load the plugin state
 - [gui](include/clap/ext/gui.h), generic gui controller
+- [voice-info](include/clap/ext/voice-info.h), let the host know how many voices the plugin has, this is important for polyphonic modulations
+- [track-info](include/clap/ext/track-info.h), give some info to the plugin about the track it belongs to
+- [tuning](include/clap/ext/draft/tuning.h), host provided microtuning (draft)
+- [triggers](include/clap/ext/draft/triggers.h), plugin's triggers, similar to parameters but stateless
 
 ## Support extensions
 
+- [thread-check](include/clap/ext/thread-check.h), check which thread you are currently on, useful for correctness validation
 - [thread-pool](include/clap/ext/thread-pool.h), use the host thread pool
+- [log](include/clap/ext/log.h), lets the host aggregate plugin logs
 - [timer-support](include/clap/ext/timer-support.h), lets the plugin register timer handlers
 - [posix-fd-support](include/clap/ext/posix-fd-support.h), lets the plugin register I/O handlers
 
-## Extra extensions
+## Deeper Host integration
 
+- [remote-controls](include/clap/ext/remote-controls.h), bank of controls that can be mapped on a controlles with 8 knobs
+- [preset-discovery](include/clap/factory/preset-discovery.h), let the host index the plugin's preset in their native file format
+- [preset-load](include/clap/ext/preset-load.h), let the host ask the plugin to load a preset
+- [param-indication](include/clap/ext/param-indication.h), let the plugin know when a physical control is mapped to a parameter and if there is automation data
 - [note-name](include/clap/ext/note-name.h), give a name to notes, useful for drum machines
-- [tuning](include/clap/ext/draft/tuning.h), host provided microtuning
-- [track-info](include/clap/ext/draft/track-info.h)
-- [quick-controls](include/clap/ext/draft/quick-controls.h), bank of controls that can be mapped on a controlles with 8 knobs
-- [file-reference](include/clap/ext/draft/file-reference.h), let the host know about the plugin's file reference, and perform "Collect & Save"
-- [check-for-update](include/clap/ext/draft/check-for-update.h), check if there is a new version of a plugin
-- [audio-ports-config](include/clap/ext/audio-ports-config.h), simple list of possible configurations
-- [surround](include/clap/ext/draft/surround.h), inspect surround channel mapping
-- [ambisonic](include/clap/ext/draft/ambisonic.h), inspect ambisonic channel mapping
+- [transport-control](include/clap/ext/draft/transport-control.h), let the plugin control the host's transport (draft)
+- [context-menu](include/clap/ext/context-menu.h), exchange context menu entries between host and plugin, let the plugin ask the host to popup its own context menu
 
 ## Third-party extensions
 

include/clap/entry.h

@@ -31,34 +31,100 @@ extern "C" {
 // Each directory should be recursively searched for files and/or bundles as appropriate in your OS
 // ending with the extension `.clap`.
 //
-// Every method must be thread-safe.
+// init and deinit in most cases are called once, in a matched pair, when the dso is loaded / unloaded.
+// In some rare situations it may be called multiple times in a process, so the functions must be defensive,
+// mutex locking and counting calls if undertaking non trivial non idempotent actions.
+//
+// Rationale:
+//
+//    The intent of the init() and deinit() functions is to provide a "normal" initialization patterh
+//    which occurs when the shared object is loaded or unloaded. As such, hosts will call each once and
+//    in matched pairs. In clap specifications prior to 1.1.11, this single-call was documented as a
+//    requirement.
+//
+//    We realized, though, that this is not a requirement hosts can meet. If hosts load a plugin
+//    which itself wraps another CLAP for instance, while also loading that same clap in its memory
+//    space, both the host and the wrapper will call init() and deinit() and have no means to communicate
+//    the state.
+//
+//    With clap 1.1.11 and beyond we are changing the spec to indicate that a host should make an
+//    absolute best effort to call init() and deinit() once, and always in matched pairs (for every
+//    init() which returns true, one deinit() should be called).
+//
+//    This takes the de-facto burden on plugin writers to deal with multiple calls into a hard requirement.
+//
+//    Most init() / deinit() pairs we have seen are the relatively trivial {return true;} and {}. But
+//    if your init() function does non-trivial one time work, the plugin author must maintain a counter
+//    and must manage a mutex lock. The most obvious implementation will maintain a static counter and a
+//    global mutex, increment the counter on each init, decrement it on each deinit, and only undertake
+//    the init or deinit action when the counter is zero.
 typedef struct clap_plugin_entry {
    clap_version_t clap_version; // initialized to CLAP_VERSION
 
-   // This function must be called first, and can only be called once.
+   // Initializes the DSO.
+   //
+   // This function must be called first, before any-other CLAP-related function or symbol from this
+   // DSO.
+   //
+   // It also must only be called once, until a later call to deinit() is made, after which init()
+   // can be called once more to re-initialize the DSO.
+   // This enables hosts to e.g. quickly load and unload a DSO for scanning its plugins, and then
+   // load it again later to actually use the plugins if needed.
+   //
+   // As stated above, even though hosts are forbidden to do so directly, multiple calls before any
+   // deinit() call may still happen. Implementations *should* take this into account, and *must*
+   // do so as of CLAP 1.11.
    //
    // It should be as fast as possible, in order to perform a very quick scan of the plugin
    // descriptors.
    //
-   // It is forbidden to display graphical user interface in this call.
-   // It is forbidden to perform user interaction in this call.
+   // It is forbidden to display graphical user interfaces in this call.
+   // It is forbidden to perform any user interaction in this call.
    //
    // If the initialization depends upon expensive computation, maybe try to do them ahead of time
    // and cache the result.
    //
-   // If init() returns false, then the host must not call deinit() nor any other clap
-   // related symbols from the DSO.
+   // Returns true on success. If init() returns false, then the DSO must be considered
+   // uninitialized, and the host must not call deinit() nor any other CLAP-related symbols from the
+   // DSO.
+   // This function also returns true in the case where the DSO is already initialized, and no
+   // actual initialization work is done in this call, as explain above.
    //
    // plugin_path is the path to the DSO (Linux, Windows), or the bundle (macOS).
+   //
+   // This function may be called on any thread, including a different one from the one a later call
+   // to deinit() (or a later init()) can be made.
+   // However, it is forbidden to call this function simultaneously from multiple threads.
+   // It is also forbidden to call it simultaneously with *any* other CLAP-related symbols from the
+   // DSO, including (but not limited to) deinit().
    bool(CLAP_ABI *init)(const char *plugin_path);
 
-   // No more calls into the DSO must be made after calling deinit().
+   // De-initializes the DSO, freeing any resources allocated or initialized by init().
+   //
+   // After this function is called, no more calls into the DSO must be made, except calling init()
+   // again to re-initialize the DSO.
+   // This means that after deinit() is called, the DSO can be considered to be in the same state
+   // as if init() was never called at all yet, enabling it to be re-initialized as needed.
+   //
+   // As stated above, even though hosts are forbidden to do so directly, multiple calls before any
+   // new init() call may still happen. Implementations *should* take this into account, and *must*
+   // do so as of CLAP 1.11.
+   //
+   // Just like init(), this function may be called on any thread, including a different one from
+   // the one init() was called from, or from the one a later init() call can be made.
+   // However, it is forbidden to call this function simultaneously from multiple threads.
+   // It is also forbidden to call it simultaneously with *any* other CLAP-related symbols from the
+   // DSO, including (but not limited to) deinit().
    void(CLAP_ABI *deinit)(void);
 
    // Get the pointer to a factory. See factory/plugin-factory.h for an example.
    //
    // Returns null if the factory is not provided.
    // The returned pointer must *not* be freed by the caller.
+   //
+   // Unlike init() and deinit(), this function can be called simultaneously by multiple threads.
+   //
+   // [thread-safe]
    const void *(CLAP_ABI *get_factory)(const char *factory_id);
 } clap_plugin_entry_t;
 

include/clap/ext/state-context.h

@@ -10,7 +10,8 @@
 /// on the context.
 ///
 /// Briefly, when loading a preset or duplicating a device, the plugin may want to partially load
-/// the state and initialize certain things differently.
+/// the state and initialize certain things differently, like handling limited resources or fixed
+/// connections to external hardware resources.
 ///
 /// Save and Load operations may have a different context.
 /// All three operations should be equivalent:
@@ -20,21 +21,28 @@
 ///        clap_plugin_state_context.save(CLAP_STATE_CONTEXT_FOR_PRESET),
 ///        CLAP_STATE_CONTEXT_FOR_PRESET)
 ///
+/// If in doubt, fallback to clap_plugin_state.
+///
 /// If the plugin implements CLAP_EXT_STATE_CONTEXT then it is mandatory to also implement
 /// CLAP_EXT_STATE.
+///
+/// It is unspecified which context is equivalent to clap_plugin_state.{save,load}()
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-static CLAP_CONSTEXPR const char CLAP_EXT_STATE_CONTEXT[] = "clap.state-context.draft/1";
+static CLAP_CONSTEXPR const char CLAP_EXT_STATE_CONTEXT[] = "clap.state-context/2";
 
 enum clap_plugin_state_context_type {
-   // suitable for duplicating a plugin instance
-   CLAP_STATE_CONTEXT_FOR_DUPLICATE = 1,
+   // suitable for storing and loading a state as a preset
+   CLAP_STATE_CONTEXT_FOR_PRESET = 1,
+
+  // suitable for duplicating a plugin instance
+   CLAP_STATE_CONTEXT_FOR_DUPLICATE = 2,
 
-   // suitable for loading a state as a preset
-   CLAP_STATE_CONTEXT_FOR_PRESET = 2,
+   // suitable for storing and loading a state within a project/song
+   CLAP_STATE_CONTEXT_FOR_PROJECT = 3,
 };
 
 typedef struct clap_plugin_state_context {

include/clap/ext/state.h

@@ -10,6 +10,10 @@
 /// values and non-parameter state. This is used to persist a plugin's state
 /// between project reloads, when duplicating and copying plugin instances, and
 /// for host-side preset management.
+///
+/// If you need to know if the save/load operation is meant for duplicating a plugin
+/// instance, for saving/loading a plugin preset or while saving/loading the project
+/// then have a look at clap_plugin_state_context_t.
 
 static CLAP_CONSTEXPR const char CLAP_EXT_STATE[] = "clap.state";