feat: wrap LV2_Lib_Descriptor

Use lv2_lib_descriptor in amp example plugin to improve lib memory handling

Signed-off-by: Christopher Arndt <chris@chrisarndt.de>

examples/amp_plugin.nim

@@ -33,14 +33,17 @@ proc instantiate(descriptor: ptr Lv2Descriptor; sampleRate: cdouble;
 
         if plug.map.isNil:
             freeShared(plug)
-            return nil
+            return cast[Lv2Handle](nil)
 
         let logPtr = cast[ptr Log](lv2FeaturesData(features, lv2LogLog))
-        plug.log.init(logPtr, plug.map)
-        plug.log.note("nymph amp plugin instance created.")
+
+        if not plug.log.setup(logPtr, plug.map):
+            plug.log.warning("LV2 Log feature not available.")
+
+        plug.log.note("nymph amp LV2 plugin instance created.")
         return cast[Lv2Handle](plug)
     except OutOfMemDefect:
-        return nil
+        return cast[Lv2Handle](nil)
 
 
 proc connectPort(instance: Lv2Handle; port: cuint;
@@ -57,7 +60,7 @@ proc connectPort(instance: Lv2Handle; port: cuint;
 
 proc activate(instance: Lv2Handle) {.cdecl.} =
     let plug = cast[ptr AmpPlugin](instance)
-    plug.log.note("nymph amp plugin activated.")
+    plug.log.note("nymph amp LV2 plugin activated.")
 
 
 proc run(instance: Lv2Handle; nSamples: cuint) {.cdecl.} =
@@ -68,12 +71,12 @@ proc run(instance: Lv2Handle; nSamples: cuint) {.cdecl.} =
 
 proc deactivate(instance: Lv2Handle) {.cdecl.} =
     let plug = cast[ptr AmpPlugin](instance)
-    plug.log.note("nymph amp plugin deactivated.")
+    plug.log.note("nymph amp LV2 plugin deactivated.")
 
 
-proc cleanup(instance: Lv2Handle) {.cdecl.} =
+proc cleanupInstance(instance: Lv2Handle) {.cdecl.} =
     let plug = cast[ptr AmpPlugin](instance)
-    plug.log.note("De-allocating nymph amp plugin instance.")
+    plug.log.note("nymph amp LV2 plugin instance will be de-allocated.")
     freeShared(cast[ptr AmpPlugin](instance))
 
 
@@ -82,26 +85,44 @@ proc extensionData(uri: cstring): pointer {.cdecl.} =
 
 
 proc NimMain() {.cdecl, importc.}
+proc NimDestroyGlobals() {.cdecl, importc.}
 
 
-let descriptor = Lv2Descriptor(
+let pluginDescriptor = Lv2Descriptor(
     uri: cstring(PluginUri),
     instantiate: instantiate,
     connectPort: connectPort,
     activate: activate,
     run: run,
     deactivate: deactivate,
-    cleanup: cleanup,
+    cleanup: cleanupInstance,
     extensionData: extensionData,
 )
 
-proc lv2Descriptor(index: cuint): ptr Lv2Descriptor {.
-                   cdecl, exportc, dynlib, extern: "lv2_descriptor".} =
 
-    echo fmt"nymph am plugin descriptor #{index} requested"
+proc cleanupLib(handle: Lv2LibHandle) {.cdecl.} =
+    echo "Cleaning up nymph amp library globals."
+    NimDestroyGlobals()
 
+
+proc getPlugin(handle: Lv2Libhandle, index: cuint): ptr Lv2Descriptor {.cdecl.} =
     if index == 0:
-        NimMain()
-        return addr(descriptor)
+        echo &"Providing nymph amp LV2 plugin descriptor #{index} to host."
+        return addr(pluginDescriptor)
 
     return nil
+
+
+let libDescriptor = Lv2LibDescriptor(
+    handle: cast[Lv2LibHandle](nil),
+    size: sizeof(Lv2LibDescriptor).cuint,
+    cleanup: cleanupLib,
+    getPlugin: getPlugin,
+)
+
+
+proc lv2LibDescriptor(bundlePath: cstring, features: ptr UncheckedArray[ptr Lv2Feature]): ptr Lv2LibDescriptor {.
+                      cdecl, dynlib, exportc: "lv2_lib_descriptor".} =
+    NimMain()
+    echo "Providing nymph amp LV2 library descriptor to host."
+    return addr(libDescriptor)

examples/faustlpf_plugin.nim

@@ -21,12 +21,12 @@ proc instantiate(descriptor: ptr Lv2Descriptor; sampleRate: cdouble;
                  bundlePath: cstring; features: ptr UncheckedArray[ptr Lv2Feature]):
                  Lv2Handle {.cdecl.} =
     try:
-        let plug = cast[ptr FaustLPFPlugin](createShared(FaustLPFPlugin))
+        let plug: ptr FaustLPFPlugin = createShared(FaustLPFPlugin)
         plug.flt = newfaustlpf()
         initfaustlpf(plug.flt, sampleRate.cint)
         return cast[Lv2Handle](plug)
     except OutOfMemDefect:
-        return nil
+        return cast[Lv2Handle](nil)
 
 
 proc connectPort(instance: Lv2Handle; port: cuint;
@@ -73,7 +73,7 @@ let descriptor = Lv2Descriptor(
 )
 
 proc lv2Descriptor(index: cuint): ptr Lv2Descriptor {.
-                   cdecl, exportc, dynlib, extern: "lv2_descriptor".} =
+                   cdecl, dynlib, exportc: "lv2_descriptor".} =
     if index == 0:
         NimMain()
         return addr(descriptor)

examples/miditranspose_plugin.nim

@@ -28,16 +28,19 @@ type
 proc instantiate(descriptor: ptr Lv2Descriptor; sampleRate: cdouble;
                  bundlePath: cstring; features: ptr UncheckedArray[ptr Lv2Feature]):
                  Lv2Handle {.cdecl.} =
-    let plug: ptr MidiTransposePlugin = createShared(MidiTransposePlugin)
-    plug.map = cast[ptr UridMap](lv2FeaturesData(features, lv2UridMap))
+    try:
+        let plug: ptr MidiTransposePlugin = createShared(MidiTransposePlugin)
+        plug.map = cast[ptr UridMap](lv2FeaturesData(features, lv2UridMap))
 
-    if plug.map.isNil:
-        freeShared(plug)
-        return nil
+        if plug.map.isNil:
+            freeShared(plug)
+            return cast[Lv2Handle](nil)
 
-    plug.midi_urid = plug.map.map(plug.map.handle, lv2MidiMidiEvent)
+        plug.midi_urid = plug.map.map(plug.map.handle, lv2MidiMidiEvent)
 
-    return cast[Lv2Handle](plug)
+        return cast[Lv2Handle](plug)
+    except OutOfMemDefect:
+        return cast[Lv2Handle](nil)
 
 
 proc connectPort(instance: Lv2Handle; port: cuint;
@@ -95,7 +98,7 @@ let descriptor = Lv2Descriptor(
 )
 
 proc lv2Descriptor(index: cuint): ptr Lv2Descriptor {.
-                   cdecl, exportc, dynlib, extern: "lv2_descriptor".} =
+                   cdecl, dynlib, exportc: "lv2_descriptor".} =
     if index == 0:
         NimMain()
         return addr(descriptor)

examples/multimodefilter_plugin.nim

@@ -27,12 +27,12 @@ proc instantiate(descriptor: ptr Lv2Descriptor; sampleRate: cdouble;
                  bundlePath: cstring; features: ptr UncheckedArray[ptr Lv2Feature]):
                  Lv2Handle {.cdecl.} =
     try:
-        let plug = createShared(SVFPlugin)
+        let plug: ptr SVFPlugin = createShared(SVFPlugin)
         plug.svf = initSVFilter(fmLowPass, sampleRate)
         plug.smoothCutoff = initParamSmooth(20.0, sampleRate)
         return cast[Lv2Handle](plug)
     except OutOfMemDefect:
-        return nil
+        return cast[Lv2Handle](nil)
 
 
 proc connectPort(instance: Lv2Handle; port: cuint;
@@ -91,7 +91,7 @@ let descriptor = Lv2Descriptor(
 )
 
 proc lv2Descriptor(index: cuint): ptr Lv2Descriptor {.
-                   cdecl, exportc, dynlib, extern: "lv2_descriptor".} =
+                   cdecl, dynlib, exportc: "lv2_descriptor".} =
     if index == 0:
         NimMain()
         return addr(descriptor)

examples/tiltfilter_plugin.nim

@@ -30,12 +30,12 @@ proc instantiate(descriptor: ptr Lv2Descriptor; sampleRate: cdouble;
                  bundlePath: cstring; features: ptr UncheckedArray[ptr Lv2Feature]):
                  Lv2Handle {.cdecl.} =
     try:
-        let plug = createShared(TiltFilterPlugin)
+        let plug: ptr TiltFilterPlugin = createShared(TiltFilterPlugin)
         plug.flt = initTiltFilter(10_000.0, 1.0, fmLowPass, sampleRate)
         plug.smoothFreq = initParamSmooth(20.0, sampleRate)
         return cast[Lv2Handle](plug)
     except OutOfMemDefect:
-        return nil
+        return cast[Lv2Handle](nil)
 
 
 proc connectPort(instance: Lv2Handle; port: cuint;
@@ -91,7 +91,7 @@ let descriptor = Lv2Descriptor(
 )
 
 proc lv2Descriptor(index: cuint): ptr Lv2Descriptor {.
-                   cdecl, exportc, dynlib, extern: "lv2_descriptor".} =
+                   cdecl, dynlib, exportc: "lv2_descriptor".} =
     if index == 0:
         NimMain()
         return addr(descriptor)

nymph.nimble

@@ -11,7 +11,7 @@ srcDir        = "src"
 
 # Dependencies
 
-requires "nim >= 2.0"
+requires "nim >= 2.2.2"
 
 # Custom tasks
 
@@ -89,7 +89,7 @@ task lv2lint, "Run lv2lint check on given example plugin":
     let ex = getExample("lv2lint")
 
     if fileExists(ex.dll):
-        exec(&"lv2lint -s NimMain -s NimDestroyGlobals -I \"{ex.bundle}\" \"{ex.uri}\"")
+        exec(&"lv2lint -s NimMain -s NimDestroyGlobals -s lv2_lib_descriptor -I \"{ex.bundle}\" \"{ex.uri}\"")
     else:
         echo &"Example '{ex.name}' shared library not found. Use task 'build_ex' to build it."
 

src/nymph/core.nim

@@ -92,29 +92,32 @@ const
     lv2CoreInstanceSampleRate* = lv2CorePrefix & "sampleRate"
     lv2CoreInstanceToggled* = lv2CorePrefix & "toggled"
 
-type Lv2Handle* = pointer
+type
+    Lv2Handle* = distinct pointer
 
-type Lv2Feature* = object
-    uri*: cstring
-    data*: pointer
+    Lv2LibHandle* = distinct pointer
 
-type Lv2Descriptor* = object
-    uri*: cstring
+    Lv2Feature* = object
+        uri*: cstring
+        data*: pointer
 
-    instantiate*: proc(descriptor: ptr Lv2Descriptor, sampleRate: cdouble, bundlePath: cstring,
-                       features: ptr UncheckedArray[ptr Lv2Feature]): Lv2Handle {.cdecl.}
+    Lv2Descriptor* = object
+        uri*: cstring
+        instantiate*: proc(descriptor: ptr Lv2Descriptor, sampleRate: cdouble, bundlePath: cstring,
+                           features: ptr UncheckedArray[ptr Lv2Feature]): Lv2Handle {.cdecl.}
+        connectPort*: proc(instance: Lv2Handle, port: cuint, dataLocation: pointer) {.cdecl.}
+        activate*: proc(instance: Lv2Handle) {.cdecl.}
+        run*: proc(instance: Lv2Handle, sampleCount: cuint) {.cdecl.}
+        deactivate*: proc(instance: Lv2Handle) {.cdecl.}
+        cleanup*: proc(instance: Lv2Handle) {.cdecl.}
+        extensionData*: proc(uri: cstring): pointer {.cdecl.}
 
-    connectPort*: proc(instance: Lv2Handle, port: cuint, dataLocation: pointer) {.cdecl.}
+    Lv2LibDescriptor* = object
+        handle*: Lv2LibHandle
+        size*: cuint
+        cleanup*: proc(handle: Lv2LibHandle) {.cdecl.}
+        getPlugin*: proc(handle: Lv2LibHandle, index: cuint): ptr Lv2Descriptor {.cdecl.}
 
-    activate*: proc(instance: Lv2Handle) {.cdecl.}
-
-    run*: proc(instance: Lv2Handle, sampleCount: cuint) {.cdecl.}
-
-    deactivate*: proc(instance: Lv2Handle) {.cdecl.}
-
-    cleanup*: proc(instance: Lv2Handle) {.cdecl.}
-
-    extensionData*: proc(uri: cstring): pointer {.cdecl.}
-
-type lv2Descriptor* = proc(index: cuint): ptr Lv2Descriptor {.cdecl.}
+    lv2Descriptor* = proc(index: cuint): ptr Lv2Descriptor {.cdecl.}
 
+    lv2LibDescriptor* = proc(bundle_path: cstring, features: ptr UncheckedArray[ptr Lv2Feature]): LV2_Lib_Descriptor {.cdecl.}

src/nymph/log.nim

@@ -21,7 +21,7 @@ const
     lv2LogLog* = lv2LogPrefix & "log"
 
 type
-    LogHandle* = distinct pointer
+    LogHandle = distinct pointer
 
     Log* = object
         handle: LogHandle 
@@ -32,7 +32,7 @@ type
         Error, Note, Trace, Warning: Urid
 
 
-proc init*(logger: var Logger, log: ptr Log, map: ptr UridMap) = 
+proc setup*(logger: var Logger, log: ptr Log, map: ptr UridMap): bool =
   logger.pLog = log
 
   if not map.isNil:
@@ -46,25 +46,27 @@ proc init*(logger: var Logger, log: ptr Log, map: ptr UridMap) =
     logger.Trace =  Urid(0)
     logger.Warning =  Urid(0)
 
+  return not (log.isNil or map.isNil)
 
-proc log*(logger: Logger, `type`: Urid, msg: string) = 
+proc log*(logger: Logger, `type`: Urid, msg: string, nl: string = "\n") =
+    let mmsg = msg & nl
     if logger.pLog.isNil:
-        echo(msg)
+        echo(mmsg)
     else:
-        logger.pLog.printf(logger.pLog.handle, `type`, msg.cstring)
+        logger.pLog.printf(logger.pLog.handle, `type`, mmsg.cstring)
         
 
-proc error*(logger: Logger, msg: string) = 
-    log(logger, logger.Error, msg)
+proc error*(logger: Logger, msg: string, nl: string = "\n") =
+    log(logger, logger.Error, msg, nl)
 
 
-proc note*(logger: Logger, msg: string) = 
-    log(logger, logger.Note, msg)
+proc note*(logger: Logger, msg: string, nl: string = "\n") =
+    log(logger, logger.Note, msg, nl)
 
 
-proc trace*(logger: Logger, msg: string) = 
-    log(logger, logger.Trace, msg)
+proc trace*(logger: Logger, msg: string, nl: string = "\n") =
+    log(logger, logger.Trace, msg, nl)
 
 
-proc warning*(logger: Logger, msg: string) = 
-    log(logger, logger.Warning, msg)
+proc warning*(logger: Logger, msg: string, nl: string = "\n") =
+    log(logger, logger.Warning, msg, nl)