* Added a --enable-plugins configure flag that builds the GL and X11 drivers

as plugins. This way, libcaca does not directly depend on those libraries.

caca/Makefile.am

@@ -3,6 +3,8 @@
 EXTRA_DIST = caca.pc.in
 DISTCLEANFILES = caca.pc
 
+AM_CPPFLAGS = -I$(top_srcdir) -I$(top_srcdir)/cucul -DPLUGINDIR=\"$(plugindir)\"
+
 pkgconfig_DATA = caca.pc
 pkgconfigdir = $(libdir)/pkgconfig
 
@@ -20,15 +22,28 @@ libcaca_la_SOURCES = \
 	event.c \
 	time.c \
 	driver_conio.c \
-	driver_gl.c \
 	driver_ncurses.c \
 	driver_raw.c \
 	driver_slang.c \
 	driver_vga.c \
 	driver_win32.c \
-	driver_x11.c \
+	$(extra_drivers) \
 	$(NULL)
-AM_CPPFLAGS = -I$(top_srcdir) -I$(top_srcdir)/cucul
 libcaca_la_LDFLAGS = -no-undefined -version-info @LT_VERSION@
 libcaca_la_LIBADD = ../cucul/libcucul.la @CACA_LIBS@
 
+if USE_PLUGINS
+plugin_LTLIBRARIES = libx11_plugin.la libgl_plugin.la
+plugindir = $(libdir)/caca
+
+libx11_plugin_la_SOURCES = driver_x11.c
+libx11_plugin_la_LDFLAGS = -no-undefined -module -no-version
+libx11_plugin_la_LIBADD = libcaca.la ../cucul/libcucul.la @X11_LIBS@
+
+libgl_plugin_la_SOURCES = driver_gl.c
+libgl_plugin_la_LDFLAGS = -no-undefined -module -no-version
+libgl_plugin_la_LIBADD = libcaca.la ../cucul/libcucul.la @GL_LIBS@
+else
+extra_drivers = driver_x11.c driver_gl.c
+endif
+

caca/caca.c

@@ -23,9 +23,15 @@
 #if !defined(__KERNEL__)
 #   include <stdlib.h>
 #   include <string.h>
+#   include <stdio.h>
 #   if defined(HAVE_ERRNO_H)
 #       include <errno.h>
 #   endif
+#   if defined(USE_PLUGINS)
+#       if defined(HAVE_DLFCN_H)
+#           include <dlfcn.h>
+#       endif
+#   endif
 #endif
 
 #include "cucul.h"
@@ -33,7 +39,15 @@
 #include "caca.h"
 #include "caca_internals.h"
 
-static int caca_select_driver(caca_display_t *dp);
+#if defined(USE_PLUGINS)
+#   define gl_install(p) caca_plugin_install("gl", p)
+#   define x11_install(p) caca_plugin_install("x11", p)
+#endif
+
+static int caca_select_driver(caca_display_t *);
+#if defined(USE_PLUGINS)
+static int caca_plugin_install(char const *, caca_display_t *);
+#endif
 
 /** \brief Attach a caca graphical context to a cucul canvas.
  *
@@ -62,9 +76,16 @@ caca_display_t * caca_create_display(cucul_canvas_t * cv)
     }
 
     dp->cv = cv;
+#if defined(USE_PLUGINS)
+    dp->plugin = NULL;
+#endif
 
     if(caca_select_driver(dp))
     {
+#if defined(USE_PLUGINS)
+        if(dp->plugin)
+            dlclose(dp->plugin);
+#endif
         free(dp);
 #if defined(HAVE_ERRNO_H)
         errno = ENODEV;
@@ -74,6 +95,10 @@ caca_display_t * caca_create_display(cucul_canvas_t * cv)
 
     if(dp->drv.init_graphics(dp))
     {
+#if defined(USE_PLUGINS)
+        if(dp->plugin)
+            dlclose(dp->plugin);
+#endif
         free(dp);
 #if defined(HAVE_ERRNO_H)
         errno = ENODEV;
@@ -128,6 +153,10 @@ caca_display_t * caca_create_display(cucul_canvas_t * cv)
 int caca_free_display(caca_display_t *dp)
 {
     dp->drv.end_graphics(dp);
+#if defined(USE_PLUGINS)
+    if(dp->plugin)
+        dlclose(dp->plugin);
+#endif
     dp->cv->refcount--;
     free(dp);
 
@@ -201,3 +230,31 @@ static int caca_select_driver(caca_display_t *dp)
     return -1;
 }
 
+#if defined(USE_PLUGINS)
+static int caca_plugin_install(char const *name, caca_display_t *dp)
+{
+    char buf[512];
+    int (*sym) (caca_display_t *);
+
+    sprintf(buf, "%s/lib%s_plugin.so", PLUGINDIR, name);
+    dp->plugin = dlopen(buf, RTLD_NOW);
+    if(!dp->plugin)
+    {
+        sprintf(buf, "lib%s_plugin.so", name);
+        dp->plugin = dlopen(buf, RTLD_NOW);
+        if(!dp->plugin)
+            return -1;
+    }
+
+    sprintf(buf, "%s_install", name);
+    sym = dlsym(dp->plugin, buf);
+    if(!sym)
+    {
+        dlclose(dp->plugin);
+        return -1;
+    }
+
+    return sym(dp);
+}
+#endif
+

caca/caca_internals.h

@@ -88,6 +88,10 @@ struct caca_display
     /* A link to our cucul canvas */
     cucul_canvas_t *cv;
 
+#if defined(USE_PLUGINS)
+    void *plugin;
+#endif
+
     /* Device-specific functions */
     struct drv
     {

configure.ac

@@ -62,10 +62,12 @@ AC_ARG_ENABLE(imlib2,
   [  --enable-imlib2         Imlib2 graphics support (default enabled)])
 
 dnl conditional builds
+AC_ARG_ENABLE(plugins,
+  [  --enable-plugins        build X11 and GL drivers as plugins])
 AC_ARG_ENABLE(doc,
   [  --enable-doc            build documentation (needs doxygen and LaTeX)])
 
-AC_CHECK_HEADERS(stdio.h stdarg.h signal.h sys/ioctl.h sys/time.h inttypes.h endian.h unistd.h arpa/inet.h netinet/in.h winsock2.h errno.h locale.h getopt.h)
+AC_CHECK_HEADERS(stdio.h stdarg.h signal.h sys/ioctl.h sys/time.h inttypes.h endian.h unistd.h arpa/inet.h netinet/in.h winsock2.h errno.h locale.h getopt.h dlfcn.h)
 AC_CHECK_FUNCS(signal ioctl vsnprintf getenv putenv strcasecmp htons)
 AC_CHECK_FUNCS(usleep gettimeofday)
 
@@ -156,7 +158,7 @@ if test "${enable_x11}" != "no"; then
     if test -n "${x_libraries}"; then X_LIBS="-L${x_libraries}"; fi
     AC_DEFINE(USE_X11, 1, Define to 1 to activate the X11 backend driver)
     CPPFLAGS="${CPPFLAGS} ${X_CFLAGS}"
-    CACA_LIBS="${CACA_LIBS} -lX11 ${X_LIBS}"
+    X11_LIBS="${X11_LIBS} -lX11 ${X_LIBS}"
     CACA_DRIVERS="${CACA_DRIVERS} x11"],
    [ac_cv_my_have_x11="no"],
    [[`if test -n "${x_libraries}"; then echo -L${x_libraries}; fi`]])
@@ -180,7 +182,7 @@ if test "${enable_gl}" != "no"; then
       break])
   if test "${ac_cv_my_have_gl}" = "yes"; then
     AC_DEFINE(USE_GL, 1, Define to 1 to activate the OpenGL backend driver)
-    CACA_LIBS="${CACA_LIBS} -lGL -lglut"
+    GL_LIBS="${GL_LIBS} -lGL -lglut"
     CACA_DRIVERS="${CACA_DRIVERS} gl"
   elif test "${enable_gl}" = "yes"; then
     AC_MSG_ERROR([cannot find OpenGL+FreeGLUT development files])
@@ -224,6 +226,15 @@ if test "${enable_vga}" = "yes"; then
 fi
 AM_CONDITIONAL(USE_KERNEL, test "${ac_cv_my_have_vga}" = "yes")
 
+if test "${enable_plugins}" = "yes"; then
+  ac_cv_my_have_plugins="yes"
+  AC_DEFINE(USE_PLUGINS, 1, Define to 1 to activate plugins)
+  CACA_LIBS="${CACA_LIBS} -ldl"
+else
+  CACA_LIBS="${CACA_LIBS} ${X11_LIBS} ${GL_LIBS}"
+fi
+AM_CONDITIONAL(USE_PLUGINS, test "${ac_cv_my_have_plugins}" = "yes")
+
 AC_MSG_CHECKING(valid output drivers)
 if test -z "${CACA_DRIVERS}"; then
   AC_MSG_RESULT(no)
@@ -237,6 +248,8 @@ fi
 AC_SUBST(MATH_LIBS)
 AC_SUBST(GETOPT_LIBS)
 AC_SUBST(CACA_LIBS)
+AC_SUBST(X11_LIBS)
+AC_SUBST(GL_LIBS)
 
 # Optimizations
 CFLAGS="${CFLAGS} -g -O2 -fno-strength-reduce -fomit-frame-pointer"
@@ -261,7 +274,7 @@ AM_CONDITIONAL(USE_NETWORK, test "${ac_cv_my_have_network}" = "yes")
 # Use Imlib2?
 if test "${enable_imlib2}" != "no"; then
   IMLIB2="no"
-  PKG_CHECK_MODULES(imlib2, imlib2, [IMLIB2="yes"], [AC_MSG_RESULT(no)])
+  PKG_CHECK_MODULES(IMLIB2, imlib2, [IMLIB2="yes"], [AC_MSG_RESULT(no)])
   if test "${IMLIB2}" = no; then
     AC_MSG_ERROR([[cannot find Imlib2 development files. Without Imlib2, cacaview will only open BMP files; if this is really what you want, re-run configure with '--disable-imlib2'.]])
   fi
@@ -269,7 +282,7 @@ fi
 
 # Build development tools?
 PANGOFT2="no"
-PKG_CHECK_MODULES(pangoft2, pangoft2, [PANGOFT2="yes"], [AC_MSG_RESULT(no)])
+PKG_CHECK_MODULES(PANGOFT2, pangoft2, [PANGOFT2="yes"], [AC_MSG_RESULT(no)])
 AM_CONDITIONAL(USE_PANGO, test "${PANGOFT2}" != "no")
 
 # Build documentation?