free-audio · abique · Jan 22, 2024 · Nov 28, 2023 · Nov 28, 2023 · Nov 30, 2023
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -50,6 +50,7 @@ add_custom_target(clap-tests)
 
 if (${CLAP_BUILD_TESTS})
     message(STATUS "Including CLAP tests, compile tests, and versions")
+    include(CheckIncludeFile)
 
     macro(clap_compile_cpp SUFFIX EXT STDC STDCPP)
         add_executable(clap-compile-${SUFFIX} EXCLUDE_FROM_ALL src/main.${EXT})
@@ -84,11 +85,17 @@ if (${CLAP_BUILD_TESTS})
     clap_compile_cpp(cpp17 cc 17 17)
     clap_compile_cpp(cpp20 cc 17 20)
 
+    check_include_file(threads.h CLAP_HAS_THREADS_H)
+
     add_library(clap-plugin-template MODULE EXCLUDE_FROM_ALL src/plugin-template.c)
     target_link_libraries(clap-plugin-template PRIVATE clap)
     set_target_properties(clap-plugin-template PROPERTIES C_STANDARD 11)
     add_dependencies(clap-tests clap-plugin-template)
 
+    if(CLAP_HAS_THREADS_H)
+        target_compile_definitions(clap-plugin-template PRIVATE CLAP_HAS_THREADS_H)
+    endif()
+
     if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
         target_link_libraries(clap-plugin-template PRIVATE -Wl,--version-script=${CMAKE_CURRENT_SOURCE_DIR}/src/linux-my_plug.version)
         target_link_libraries(clap-plugin-template PRIVATE -Wl,-z,defs)

diff --git a/ChangeLog.md b/ChangeLog.md
@@ -1,3 +1,77 @@
+# Changes in 1.2.0
+
+## New conventions
+
+* [extension-id](conventions/extension-id.md): introduce some rules about extension ID naming.
+
+## Stabilize extensions
+
+* `CLAP_EXT_AMBISONIC`
+* `CLAP_EXT_AUDIO_PORTS_ACTIVATION`
+* `CLAP_EXT_CONFIGURABLE_AUDIO_PORTS`
+* `CLAP_EXT_CONTEXT_MENU`
+* `CLAP_EXT_PARAM_INDICATION`
+* `CLAP_EXT_PRESET_LOAD`
+* `CLAP_EXT_REMOTE_CONTROLS`
+* `CLAP_EXT_STATE_CONTEXT`
+* `CLAP_EXT_SURROUND`
+* `CLAP_EXT_TRACK_INFO`
+
+### Notes regarding extension ID change after draft stabilization
+
+We changed the extension ID in the process of stabilization which leads to a **break**.
+
+To mitigate this transition, we've provided compatibility extension IDs which can be used to match and use the latest draft extensions as they are 100% compatible.
+
+For example, `CLAP_EXT_CONTEXT_MENU` for the stable ID and `CLAP_EXT_CONTEXT_MENU_COMPAT` for the draft ID.
+
+As you can see in [extension-id](conventions/extension-id.md), we introduced some rules, so this kind of break won't happen again.
+
+We may decide to remove the `*_COMPAT` IDs in the future once their usage becomes antiquated.
+
+## 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.
+* `CLAP_EXT_CV` the interface wasn't satisfying.
+
+## Stabilize factory
+
+* `CLAP_PRESET_DISCOVERY_FACTORY_ID`
+
+Note: we kept the last draft factory ID in order to not break plugins already using it.
+
+## Plugin State Converter
+
+* Introduction of a new factory which provides a plugin state convertion mechanism.
+
+## Refactoring
+
+* `clap_plugin_id_t` was renamed to `clap_universal_plugin_id_t` to make it clear that it can describe more than just a CLAP plugin ID.
+* `clap_timestamp_t` was renamed to `clap_timestamp` to be consistent with other types, like e.g. `clap_id`. Also it was moved to a separate header as `CLAP_PRESET_DISCOVERY_FACTORY_ID` was stabilized.
+
+## Documentation
+
+* [events.h](include/clap/events.h): Clarify how "Port Channel Key NoteID" matching works
+* [events.h](include/clap/events.h): Clarify how `clap_event_note` fields map to MIDI, Host, etc...
+* [events.h](include/clap/events.h): Expand clap note expression documentation
+* [plugin.h](include/clap/plugin.h): Style cleanup
+* [params.h](include/clap/ext/params.h): Fix incorrect function name reference
+* [latency.h](include/clap/ext/latency.h): Require the plugin to be activated to get the latency and clarify that the latency can only be fetched when the plugin is activated
+
+## Plugin Template
+
+* [plugin-template.c](src/plugin-template.c): implement thread-safe plugin entry init counter
+
+## Organization
+
+* `clap.h` no longer includes headers from `ext/draft` or `factory/draft`. Draft extension and factory headers must now be explicitly included, either individually or via the `all.h` header.
+
+## Other changes
+
+* [voice-info.h](include/clap/ext/voice-info.h): Make the voice info id `CLAP_CONSTEXPR` like all other ids
+* [preset-load.h](include/clap/ext/preset-load.h): Make the preset load id and compat id `CLAP_CONSTEXPR` like all other ids
+
 # Changes in 1.1.10
 
 * [params.h](include/clap/ext/params.h): add `CLAP_PARAM_IS_ENUM` flag.

diff --git a/README.md b/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)
@@ -32,6 +32,7 @@ that is, a plugin binary compiled with CLAP 1.x can be loaded by any other
 CLAP 1.y.
 
 To work with CLAP, include [clap/clap.h](include/clap/clap.h).
+To also include the draft extensions, include [clap/all.h](include/clap/all.h).
 
 The two most important objects are `clap_host` and `clap_plugin`.
 
@@ -81,34 +82,44 @@ 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
+  - [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, meant to be exposed to the user
+  - [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
 

diff --git a/conventions/extension-id.md b/conventions/extension-id.md
@@ -0,0 +1,32 @@
+# Extension ID
+
+## Naming
+
+The extension shall be named in the form: `clap.$NAME/$REV`.
+Where:
+- `$NAME` is the name of the exension.
+- `$REV` is the revision of the extension. This is an integer that is incremented for each iteration. It should start at 1.
+
+For extensions made by third-parties and not officially published by the CLAP project, please use the following form: `$REVERSE_URI.$NAME/$REV`.
+Where:
+- `$REVERSE_URI` would be something like `com.bitwig`.
+
+## Draft
+
+An extension is considered a draft extension if it is in the [draft](../include/clap/ext/draft/) folder.
+Make sure to also include it in [all.h](../include/clap/all.h).
+
+When the extension is migrating from draft to stable, its extension ID must not change.
+Move its inclusion from [all.h](../include/clap/all.h) into [clap.h](../include/clap/clap.h).
+
+All extensions must go though the draft phase first.
+
+## For factory ID
+
+Everything about the extension id symmetrically applies to factory id.
+
+## History
+
+Before version 1.2.0 when this document was written, existing extensions didn't honor these rules.
+We wanted to stabilize some draft extensions without breaking compatibility, yet their extension IDs contained the string `draft`.
+While these strings weren't user-facing, we still wanted to remove them, so we updated the extension IDs according to this document and introduced IDs with `_COMPAT` suffixes to provide backward compatibility with the draft versions.
diff --git a/include/clap/all.h b/include/clap/all.h
@@ -0,0 +1,12 @@
+#pragma once
+
+#include "clap.h"
+
+#include "factory/draft/plugin-invalidation.h"
+#include "factory/draft/plugin-state-converter.h"
+
+#include "ext/draft/extensible-audio-ports.h"
+#include "ext/draft/resource-directory.h"
+#include "ext/draft/transport-control.h"
+#include "ext/draft/triggers.h"
+#include "ext/draft/tuning.h"
diff --git a/include/clap/clap.h b/include/clap/clap.h
@@ -28,44 +28,37 @@
 #include "entry.h"
 
 #include "factory/plugin-factory.h"
-#include "factory/draft/plugin-invalidation.h"
-#include "factory/draft/preset-discovery.h"
+#include "factory/preset-discovery.h"
 
 #include "plugin.h"
 #include "plugin-features.h"
 #include "host.h"
+#include "universal-plugin-id.h"
 
+#include "ext/ambisonic.h"
+#include "ext/audio-ports-activation.h"
 #include "ext/audio-ports-config.h"
 #include "ext/audio-ports.h"
+#include "ext/configurable-audio-ports.h"
+#include "ext/context-menu.h"
 #include "ext/event-registry.h"
 #include "ext/gui.h"
 #include "ext/latency.h"
 #include "ext/log.h"
 #include "ext/note-name.h"
 #include "ext/note-ports.h"
+#include "ext/param-indication.h"
 #include "ext/params.h"
 #include "ext/posix-fd-support.h"
+#include "ext/preset-load.h"
+#include "ext/remote-controls.h"
 #include "ext/render.h"
+#include "ext/state-context.h"
 #include "ext/state.h"
+#include "ext/surround.h"
 #include "ext/tail.h"
 #include "ext/thread-check.h"
 #include "ext/thread-pool.h"
 #include "ext/timer-support.h"
+#include "ext/track-info.h"
 #include "ext/voice-info.h"
-
-#include "ext/draft/ambisonic.h"
-#include "ext/draft/audio-ports-activation.h"
-#include "ext/draft/context-menu.h"
-#include "ext/draft/cv.h"
-#include "ext/draft/midi-mappings.h"
-#include "ext/draft/param-indication.h"
-#include "ext/draft/preset-load.h"
-#include "ext/draft/remote-controls.h"
-#include "ext/draft/resource-directory.h"
-#include "ext/draft/state-context.h"
-#include "ext/draft/surround.h"
-#include "ext/draft/track-info.h"
-#include "ext/draft/triggers.h"
-#include "ext/draft/tuning.h"
-#include "ext/draft/configurable-audio-ports.h"
-#include "ext/draft/extensible-audio-ports.h"
diff --git a/include/clap/entry.h b/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 1.2.0, 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 1.2.0 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 1.2.0.
    //
    // 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 1.2.0.
+   //
+   // 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;