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authorDavid Robillard <d@drobilla.net>2022-07-07 18:59:32 -0400
committerDavid Robillard <d@drobilla.net>2022-07-17 18:14:00 -0400
commit1eccbe4355685b322194df72b5de2382d5290b3b (patch)
tree0677b5c2f577a5024c351a164527f4bdd91a639b /include/lv2/worker/worker.h
parentd4a970f6962dda28133290194832b726b566ddab (diff)
downloadlv2-1eccbe4355685b322194df72b5de2382d5290b3b.tar.xz
Rearrange source tree to be directly usable by dependants
This allows the LV2 source distribution to be used as an include path for compilers and an LV2_PATH for applications, at the expense of self-contained bundles. That's a nice idea, but it made LV2 itself weird and annoying to depend on. This rearranges things so that directories in the source tree correspond more closely to installation directories. To make this possible, the "aux" directory in the documentation output has been changed to "style", to avoid the reserved name "aux" on Windows.
Diffstat (limited to 'include/lv2/worker/worker.h')
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1 files changed, 183 insertions, 0 deletions
diff --git a/include/lv2/worker/worker.h b/include/lv2/worker/worker.h
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+/*
+ Copyright 2012-2016 David Robillard <d@drobilla.net>
+
+ Permission to use, copy, modify, and/or distribute this software for any
+ purpose with or without fee is hereby granted, provided that the above
+ copyright notice and this permission notice appear in all copies.
+
+ THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#ifndef LV2_WORKER_H
+#define LV2_WORKER_H
+
+/**
+ @defgroup worker Worker
+ @ingroup lv2
+
+ Support for non-realtime plugin operations.
+
+ See <http://lv2plug.in/ns/ext/worker> for details.
+
+ @{
+*/
+
+#include "lv2/core/lv2.h"
+
+#include <stdint.h>
+
+// clang-format off
+
+#define LV2_WORKER_URI "http://lv2plug.in/ns/ext/worker" ///< http://lv2plug.in/ns/ext/worker
+#define LV2_WORKER_PREFIX LV2_WORKER_URI "#" ///< http://lv2plug.in/ns/ext/worker#
+
+#define LV2_WORKER__interface LV2_WORKER_PREFIX "interface" ///< http://lv2plug.in/ns/ext/worker#interface
+#define LV2_WORKER__schedule LV2_WORKER_PREFIX "schedule" ///< http://lv2plug.in/ns/ext/worker#schedule
+
+// clang-format on
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ Status code for worker functions.
+*/
+typedef enum {
+ LV2_WORKER_SUCCESS = 0, /**< Completed successfully. */
+ LV2_WORKER_ERR_UNKNOWN = 1, /**< Unknown error. */
+ LV2_WORKER_ERR_NO_SPACE = 2 /**< Failed due to lack of space. */
+} LV2_Worker_Status;
+
+/** Opaque handle for LV2_Worker_Interface::work(). */
+typedef void* LV2_Worker_Respond_Handle;
+
+/**
+ A function to respond to run() from the worker method.
+
+ The `data` MUST be safe for the host to copy and later pass to
+ work_response(), and the host MUST guarantee that it will be eventually
+ passed to work_response() if this function returns LV2_WORKER_SUCCESS.
+*/
+typedef LV2_Worker_Status (*LV2_Worker_Respond_Function)(
+ LV2_Worker_Respond_Handle handle,
+ uint32_t size,
+ const void* data);
+
+/**
+ Plugin Worker Interface.
+
+ This is the interface provided by the plugin to implement a worker method.
+ The plugin's extension_data() method should return an LV2_Worker_Interface
+ when called with LV2_WORKER__interface as its argument.
+*/
+typedef struct {
+ /**
+ The worker method. This is called by the host in a non-realtime context
+ as requested, possibly with an arbitrary message to handle.
+
+ A response can be sent to run() using `respond`. The plugin MUST NOT
+ make any assumptions about which thread calls this method, except that
+ there are no real-time requirements and only one call may be executed at
+ a time. That is, the host MAY call this method from any non-real-time
+ thread, but MUST NOT make concurrent calls to this method from several
+ threads.
+
+ @param instance The LV2 instance this is a method on.
+ @param respond A function for sending a response to run().
+ @param handle Must be passed to `respond` if it is called.
+ @param size The size of `data`.
+ @param data Data from run(), or NULL.
+ */
+ LV2_Worker_Status (*work)(LV2_Handle instance,
+ LV2_Worker_Respond_Function respond,
+ LV2_Worker_Respond_Handle handle,
+ uint32_t size,
+ const void* data);
+
+ /**
+ Handle a response from the worker. This is called by the host in the
+ run() context when a response from the worker is ready.
+
+ @param instance The LV2 instance this is a method on.
+ @param size The size of `body`.
+ @param body Message body, or NULL.
+ */
+ LV2_Worker_Status (*work_response)(LV2_Handle instance,
+ uint32_t size,
+ const void* body);
+
+ /**
+ Called when all responses for this cycle have been delivered.
+
+ Since work_response() may be called after run() finished, this provides
+ a hook for code that must run after the cycle is completed.
+
+ This field may be NULL if the plugin has no use for it. Otherwise, the
+ host MUST call it after every run(), regardless of whether or not any
+ responses were sent that cycle.
+ */
+ LV2_Worker_Status (*end_run)(LV2_Handle instance);
+} LV2_Worker_Interface;
+
+/** Opaque handle for LV2_Worker_Schedule. */
+typedef void* LV2_Worker_Schedule_Handle;
+
+/**
+ Schedule Worker Host Feature.
+
+ The host passes this feature to provide a schedule_work() function, which
+ the plugin can use to schedule a worker call from run().
+*/
+typedef struct {
+ /**
+ Opaque host data.
+ */
+ LV2_Worker_Schedule_Handle handle;
+
+ /**
+ Request from run() that the host call the worker.
+
+ This function is in the audio threading class. It should be called from
+ run() to request that the host call the work() method in a non-realtime
+ context with the given arguments.
+
+ This function is always safe to call from run(), but it is not
+ guaranteed that the worker is actually called from a different thread.
+ In particular, when free-wheeling (for example, during offline
+ rendering), the worker may be executed immediately. This allows
+ single-threaded processing with sample accuracy and avoids timing
+ problems when run() is executing much faster or slower than real-time.
+
+ Plugins SHOULD be written in such a way that if the worker runs
+ immediately, and responses from the worker are delivered immediately,
+ the effect of the work takes place immediately with sample accuracy.
+
+ The `data` MUST be safe for the host to copy and later pass to work(),
+ and the host MUST guarantee that it will be eventually passed to work()
+ if this function returns LV2_WORKER_SUCCESS.
+
+ @param handle The handle field of this struct.
+ @param size The size of `data`.
+ @param data Message to pass to work(), or NULL.
+ */
+ LV2_Worker_Status (*schedule_work)(LV2_Worker_Schedule_Handle handle,
+ uint32_t size,
+ const void* data);
+} LV2_Worker_Schedule;
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+/**
+ @}
+*/
+
+#endif /* LV2_WORKER_H */