comparison audioio/AudioJACKTarget.cpp @ 2:42a78f0e8fe2

* Use pkgconfig to look up Vamp library and header details if possible
* Use runtime dlopen for JACK library when JACK support is enabled in a static
  build on Linux

 #include <iostream>
 #include <cmath>
 
 //#define DEBUG_AUDIO_JACK_TARGET 1
 
+#ifdef BUILD_STATIC
+#ifdef Q_OS_LINUX
+
+// Some lunacy to enable JACK support in static builds.  JACK isn't
+// supposed to be linked statically, because it depends on a
+// consistent shared memory layout between client library and daemon,
+// so it's very fragile in the face of version mismatches.
+//
+// Therefore for static builds on Linux we avoid linking against JACK
+// at all during the build, instead using dlopen and runtime symbol
+// lookup to switch on JACK support at runtime.  The following big
+// mess (down to the #endifs) is the code that implements this.
+
+static void *symbol(const char *name)
+{
+    static bool attempted = false;
+    static void *library = 0;
+    static std::map<const char *, void *> symbols;
+    if (symbols.find(name) != symbols.end()) return symbols[name];
+    if (!library) {
+        if (!attempted) {
+            library = ::dlopen("libjack.so.1", RTLD_NOW);
+            if (!library) library = ::dlopen("libjack.so.0", RTLD_NOW);
+            if (!library) library = ::dlopen("libjack.so", RTLD_NOW);
+            if (!library) {
+                std::cerr << "WARNING: AudioJACKTarget: Failed to load JACK library: "
+                          << ::dlerror() << " (tried .so, .so.0, .so.1)"
+                          << std::endl;
+            }
+            attempted = true;
+        }
+        if (!library) return 0;
+    }
+    void *symbol = ::dlsym(library, name);
+    if (!symbol) {
+        std::cerr << "WARNING: AudioJACKTarget: Failed to locate symbol "
+                  << name << ": " << ::dlerror() << std::endl;
+    }
+    symbols[name] = symbol;
+    return symbol;
+}
+
+static int dynamic_jack_set_process_callback(jack_client_t *client,
+                                             JackProcessCallback process_callback,
+                                             void *arg)
+{
+    typedef int (*func)(jack_client_t *client,
+                        JackProcessCallback process_callback,
+                        void *arg);
+    void *s = symbol("jack_set_process_callback");
+    if (!s) return 1;
+    func f = (func)s;
+    return f(client, process_callback, arg);
+}
+
+static const char **dynamic_jack_get_ports(jack_client_t *client, 
+                                           const char *port_name_pattern, 
+                                           const char *type_name_pattern, 
+                                           unsigned long flags)
+{
+    typedef const char **(*func)(jack_client_t *client, 
+                                 const char *port_name_pattern, 
+                                 const char *type_name_pattern, 
+                                 unsigned long flags);
+    void *s = symbol("jack_get_ports");
+    if (!s) return 0;
+    func f = (func)s;
+    return f(client, port_name_pattern, type_name_pattern, flags);
+}
+
+static jack_port_t *dynamic_jack_port_register(jack_client_t *client,
+                                               const char *port_name,
+                                               const char *port_type,
+                                               unsigned long flags,
+                                               unsigned long buffer_size)
+{
+    typedef jack_port_t *(*func)(jack_client_t *client,
+                                 const char *port_name,
+                                 const char *port_type,
+                                 unsigned long flags,
+                                 unsigned long buffer_size);
+    void *s = symbol("jack_port_register");
+    if (!s) return 0;
+    func f = (func)s;
+    return f(client, port_name, port_type, flags, buffer_size);
+}
+
+static int dynamic_jack_connect(jack_client_t *client,
+                                const char *source,
+                                const char *dest)
+{
+    typedef int (*func)(jack_client_t *client,
+                        const char *source,
+                        const char *dest);
+    void *s = symbol("jack_connect");
+    if (!s) return 1;
+    func f = (func)s;
+    return f(client, source, dest);
+}
+
+static void *dynamic_jack_port_get_buffer(jack_port_t *port,
+                                          jack_nframes_t sz)
+{
+    typedef void *(*func)(jack_port_t *, jack_nframes_t);
+    void *s = symbol("jack_port_get_buffer");
+    if (!s) return 0;
+    func f = (func)s;
+    return f(port, sz);
+}
+
+static int dynamic_jack_port_unregister(jack_client_t *client,
+                                        jack_port_t *port)
+{
+    typedef int(*func)(jack_client_t *, jack_port_t *);
+    void *s = symbol("jack_port_unregister");
+    if (!s) return 0;
+    func f = (func)s;
+    return f(client, port);
+}
+
+#define dynamic1(rv, name, argtype, failval) \
+    static rv dynamic_##name(argtype arg) { \
+        typedef rv (*func) (argtype); \
+        void *s = symbol(#name); \
+        if (!s) return failval; \
+        func f = (func) s; \
+        return f(arg); \
+    }
+
+dynamic1(jack_client_t *, jack_client_new, const char *, 0);
+dynamic1(jack_nframes_t, jack_get_buffer_size, jack_client_t *, 0);
+dynamic1(jack_nframes_t, jack_get_sample_rate, jack_client_t *, 0);
+dynamic1(int, jack_activate, jack_client_t *, 1);
+dynamic1(int, jack_deactivate, jack_client_t *, 1);
+dynamic1(int, jack_client_close, jack_client_t *, 1);
+dynamic1(jack_nframes_t, jack_port_get_latency, jack_port_t *, 0);
+dynamic1(const char *, jack_port_name, const jack_port_t *, 0);
+
+#define jack_client_new dynamic_jack_client_new
+#define jack_get_buffer_size dynamic_jack_get_buffer_size
+#define jack_get_sample_rate dynamic_jack_get_sample_rate
+#define jack_set_process_callback dynamic_jack_set_process_callback
+#define jack_activate dynamic_jack_activate
+#define jack_deactivate dynamic_jack_deactivate
+#define jack_client_close dynamic_jack_client_close
+#define jack_get_ports dynamic_jack_get_ports
+#define jack_port_register dynamic_jack_port_register
+#define jack_port_unregister dynamic_jack_port_unregister
+#define jack_port_get_latency dynamic_jack_port_get_latency
+#define jack_port_name dynamic_jack_port_name
+#define jack_connect dynamic_jack_connect
+#define jack_port_get_buffer dynamic_jack_port_get_buffer
+
+#endif
+#endif
+
 AudioJACKTarget::AudioJACKTarget(AudioCallbackPlaySource *source) :
     AudioCallbackPlayTarget(source),
     m_client(0),
     m_bufferSize(0),
     m_sampleRate(0)