Add logging API

7 files changed, 104 insertions, 18 deletions

diff --git a/pugl/detail/implementation.c b/pugl/detail/implementation.c
index 7764bbd..9d3d6b4 100644
--- a/pugl/detail/implementation.c
+++ b/pugl/detail/implementation.c
@@ -22,9 +22,34 @@
 #include "pugl/pugl.h"
 
 #include <stdbool.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
+static const char*
+puglLogLevelPrefix(const PuglLogLevel level)
+{
+	switch (level) {
+	case PUGL_LOG_LEVEL_ERR:
+		return "error: ";
+	case PUGL_LOG_LEVEL_WARNING:
+		return "warning: ";
+	case PUGL_LOG_LEVEL_INFO:
+	case PUGL_LOG_LEVEL_DEBUG:
+		return "";
+	}
+
+	return "";
+}
+
+static void
+puglDefaultLogFunc(PuglWorld*   PUGL_UNUSED(world),
+                   PuglLogLevel level,
+                   const char*  msg)
+{
+	fprintf(stderr, "%s%s", puglLogLevelPrefix(level), msg);
+}
+
 const char*
 puglStrerror(const PuglStatus status)
 {
@@ -98,6 +123,9 @@ puglNewWorld(void)
 	}
 
 	world->startTime = puglGetTime(world);
+	world->logFunc   = puglDefaultLogFunc;
+	world->logLevel  = PUGL_LOG_LEVEL_INFO;
+
 	puglSetString(&world->className, "Pugl");
 
 	return world;
@@ -125,6 +153,22 @@ puglGetWorldHandle(PuglWorld* world)
 }
 
 PuglStatus
+puglSetLogFunc(PuglWorld* world, PuglLogFunc logFunc)
+{
+	world->logFunc = logFunc;
+
+	return PUGL_SUCCESS;
+}
+
+PuglStatus
+puglSetLogLevel(PuglWorld* world, PuglLogLevel level)
+{
+	world->logLevel = level;
+
+	return PUGL_SUCCESS;
+}
+
+PuglStatus
 puglSetClassName(PuglWorld* const world, const char* const name)
 {
 	puglSetString(&world->className, name);
diff --git a/pugl/detail/types.h b/pugl/detail/types.h
index 2e41003..08a7854 100644
--- a/pugl/detail/types.h
+++ b/pugl/detail/types.h
@@ -78,10 +78,12 @@ struct PuglViewImpl {
 struct PuglWorldImpl {
 	PuglWorldInternals* impl;
 	PuglWorldHandle     handle;
+	PuglLogFunc         logFunc;
 	char*               className;
 	double              startTime;
 	size_t              numViews;
 	PuglView**          views;
+	PuglLogLevel        logLevel;
 };
 
 /** Opaque surface used by graphics backend. */
diff --git a/pugl/detail/win.c b/pugl/detail/win.c
index bf60ddb..0c8078f 100644
--- a/pugl/detail/win.c
+++ b/pugl/detail/win.c
@@ -29,7 +29,6 @@
 
 #include <math.h>
 #include <stdbool.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <wctype.h>
diff --git a/pugl/detail/x11.c b/pugl/detail/x11.c
index 25693a2..ee5fb69 100644
--- a/pugl/detail/x11.c
+++ b/pugl/detail/x11.c
@@ -41,7 +41,6 @@
 #include <math.h>
 #include <stdbool.h>
 #include <stdint.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
@@ -94,9 +93,7 @@ puglInitWorldInternals(void)
 	XSetLocaleModifiers("");
 	if (!(impl->xim = XOpenIM(display, NULL, NULL, NULL))) {
 		XSetLocaleModifiers("@im=");
-		if (!(impl->xim = XOpenIM(display, NULL, NULL, NULL))) {
-			fprintf(stderr, "warning: XOpenIM failed\n");
-		}
+		impl->xim = XOpenIM(display, NULL, NULL, NULL);
 	}
 
 	XFlush(display);
@@ -252,7 +249,9 @@ puglCreateWindow(PuglView* view, const char* title)
 	                            XNClientWindow, win,
 	                            XNFocusWindow,  win,
 	                            NULL))) {
-		fprintf(stderr, "warning: XCreateIC failed\n");
+		view->world->logFunc(view->world,
+		                     PUGL_LOG_LEVEL_WARNING,
+		                     "XCreateID failed\n");
 	}
 
 	const PuglEvent createEvent = {{PUGL_CREATE, 0}};
diff --git a/pugl/detail/x11_cairo.c b/pugl/detail/x11_cairo.c
index b084f5a..d06c0d5 100644
--- a/pugl/detail/x11_cairo.c
+++ b/pugl/detail/x11_cairo.c
@@ -28,7 +28,6 @@
 #include <cairo-xlib.h>
 #include <cairo.h>
 
-#include <stdio.h>
 #include <stdlib.h>
 
 typedef struct {
diff --git a/pugl/detail/x11_gl.c b/pugl/detail/x11_gl.c
index 5e4a5ca..fec0899 100644
--- a/pugl/detail/x11_gl.c
+++ b/pugl/detail/x11_gl.c
@@ -85,23 +85,28 @@ puglX11GlConfigure(PuglView* view)
 	int          n_fbc = 0;
 	GLXFBConfig* fbc   = glXChooseFBConfig(display, screen, attrs, &n_fbc);
 	if (n_fbc <= 0) {
-		fprintf(stderr, "error: Failed to create GL context\n");
 		return PUGL_CREATE_CONTEXT_FAILED;
 	}
 
 	surface->fb_config = fbc[0];
 	impl->vi           = glXGetVisualFromFBConfig(impl->display, fbc[0]);
 
-	printf("Using visual 0x%lX: R=%d G=%d B=%d A=%d D=%d"
-	       " DOUBLE=%d SAMPLES=%d\n",
-	       impl->vi->visualid,
-	       puglX11GlGetAttrib(display, fbc[0], GLX_RED_SIZE),
-	       puglX11GlGetAttrib(display, fbc[0], GLX_GREEN_SIZE),
-	       puglX11GlGetAttrib(display, fbc[0], GLX_BLUE_SIZE),
-	       puglX11GlGetAttrib(display, fbc[0], GLX_ALPHA_SIZE),
-	       puglX11GlGetAttrib(display, fbc[0], GLX_DEPTH_SIZE),
-	       puglX11GlGetAttrib(display, fbc[0], GLX_DOUBLEBUFFER),
-	       puglX11GlGetAttrib(display, fbc[0], GLX_SAMPLES));
+	char msg[128];
+
+	snprintf(
+	    msg,
+	    sizeof(msg),
+	    "Using visual 0x%lX: R=%d G=%d B=%d A=%d D=%d DOUBLE=%d SAMPLES=%d\n",
+	    impl->vi->visualid,
+	    puglX11GlGetAttrib(display, fbc[0], GLX_RED_SIZE),
+	    puglX11GlGetAttrib(display, fbc[0], GLX_GREEN_SIZE),
+	    puglX11GlGetAttrib(display, fbc[0], GLX_BLUE_SIZE),
+	    puglX11GlGetAttrib(display, fbc[0], GLX_ALPHA_SIZE),
+	    puglX11GlGetAttrib(display, fbc[0], GLX_DEPTH_SIZE),
+	    puglX11GlGetAttrib(display, fbc[0], GLX_DOUBLEBUFFER),
+	    puglX11GlGetAttrib(display, fbc[0], GLX_SAMPLES));
+
+	view->world->logFunc(view->world, PUGL_LOG_LEVEL_INFO, msg);
 
 	XFree(fbc);
 
diff --git a/pugl/pugl.h b/pugl/pugl.h
index 718e76a..c5f8969 100644
--- a/pugl/pugl.h
+++ b/pugl/pugl.h
@@ -491,6 +491,27 @@ typedef struct PuglWorldImpl PuglWorld;
 typedef void* PuglWorldHandle;
 
 /**
+   A log message level, compatible with syslog.
+*/
+typedef enum {
+	PUGL_LOG_LEVEL_ERR     = 3, ///< Error
+	PUGL_LOG_LEVEL_WARNING = 4, ///< Warning
+	PUGL_LOG_LEVEL_INFO    = 6, ///< Informational message
+	PUGL_LOG_LEVEL_DEBUG   = 7  ///< Debug message
+} PuglLogLevel;
+
+/**
+   A function called to report log messages.
+
+   @param world The world that produced this log message.
+   @param level Log level.
+   @param msg Message string.
+*/
+typedef void (*PuglLogFunc)(PuglWorld*   world,
+                            PuglLogLevel level,
+                            const char*  msg);
+
+/**
    Create a new world.
 
    @return A new world, which must be later freed with puglFreeWorld().
@@ -533,6 +554,23 @@ PUGL_API void*
 puglGetNativeWorld(PuglWorld* world);
 
 /**
+   Set the function to call to log a message.
+
+   This will be called to report any log messages generated internally by Pugl
+   which are enabled according to the log level.
+*/
+PUGL_API PuglStatus
+puglSetLogFunc(PuglWorld* world, PuglLogFunc logFunc);
+
+/**
+   Set the level of log messages to emit.
+
+   Any log messages with a level less than or equal to `level` will be emitted.
+*/
+PUGL_API PuglStatus
+puglSetLogLevel(PuglWorld* world, PuglLogLevel level);
+
+/**
    Set the class name of the application.
 
    This is a stable identifier for the application, used as the window