* mzscheme code can now dynamically load libraries, that are needed

  at runtime. This allows for code to be generated at some site, and
  distributed without the need for SWIG.

  The distribution needs only the header filesfor which the code has been
   generated. Linking is done at runtime, by loading the dynamic libraries.

   Functions are resolved when needed.

   Though somewhat inefficient, it provides for a way to distribute code
   or binaries that are independent of the version of the installed libraries,

   which comes in especially handy for e.g. binding against Gtk.


git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@9211 626c5289-ae23-0410-ae9c-e8d60b6d4f22

1 files changed, 194 insertions, 0 deletions

diff --git a/Lib/mzscheme/mzrun.swg b/Lib/mzscheme/mzrun.swg
index 52aa87aca..6a71fb79a 100644
--- a/Lib/mzscheme/mzrun.swg
+++ b/Lib/mzscheme/mzrun.swg
@@ -252,6 +252,199 @@ SWIG_MzScheme_new_scheme_struct (Scheme_Env* env, const char* basename,
     return new_type;
 }
 
+/*** DLOPEN PATCH ******************************************************
+ * Contributed by Hans Oesterholt-Dijkema (jan. 2006)
+ ***********************************************************************/
+
+#if defined(_WIN32) || defined(__WIN32__)
+#define __OS_WIN32
+#endif
+
+#ifdef __OS_WIN32
+#include <windows.h>
+#else
+#include <dlfcn.h>
+#endif
+
+  static char **mz_dlopen_libraries=NULL;
+  static void **mz_libraries=NULL;
+  static char **mz_dynload_libpaths=NULL;
+
+  static void mz_set_dlopen_libraries(const char *_libs)
+  {
+    int   i,k,n;
+    int   mz_dynload_debug=(1==0);
+    char *extra_paths[1000];
+    char *EP;
+    
+    {
+      char *dbg=getenv("MZ_DYNLOAD_DEBUG");
+      if (dbg!=NULL) {
+	mz_dynload_debug=atoi(dbg);
+      }
+    }
+
+    {
+      char *ep=getenv("MZ_DYNLOAD_LIBPATH");
+      int   i,k,j;
+      k=0;
+      if (ep!=NULL) {
+	EP=strdup(ep);
+	for(i=0,j=0;EP[i]!='\0';i++) {
+	  if (EP[i]==':') {
+	    EP[i]='\0';
+	    extra_paths[k++]=&EP[j];
+	    j=i+1;
+	  }
+	}
+	if (j!=i) {
+	  extra_paths[k++]=&EP[j];
+	}
+      }
+      else {
+	EP=strdup("");
+      }
+      extra_paths[k]=NULL;
+      k+=1;
+
+      if (mz_dynload_debug) {
+	fprintf(stderr,"SWIG:mzscheme:MZ_DYNLOAD_LIBPATH=%s\n",(ep==NULL) ? "(null)" : ep);
+	fprintf(stderr,"SWIG:mzscheme:extra_paths[%d]\n",k-1);
+	for(i=0;i<k-1;i++) {
+	  fprintf(stderr,"SWIG:mzscheme:extra_paths[%d]=%s\n",i,extra_paths[i]);
+	}
+      }
+
+      mz_dynload_libpaths=(char **) malloc(sizeof(char *)*k);
+      for(i=0;i<k;i++) {
+	if (extra_paths[i]!=NULL) {
+	  mz_dynload_libpaths[i]=strdup(extra_paths[i]);
+	}
+	else {
+	  mz_dynload_libpaths[i]=NULL;
+	}
+      }
+
+      if (mz_dynload_debug) {
+	int i;
+	for(i=0;extra_paths[i]!=NULL;i++) {
+	  fprintf(stderr,"SWIG:mzscheme:%s\n",extra_paths[i]);
+	}
+      }
+    }
+
+    {
+#ifdef MZ_DYNLOAD_LIBS
+      char *libs=(char *) malloc((strlen(MZ_DYNLOAD_LIBS)+1)*sizeof(char));
+      strcpy(libs,MZ_DYNLOAD_LIBS);
+#else
+      char *libs=(char *) malloc((strlen(_libs)+1)*sizeof(char));
+      strcpy(libs,_libs);
+#endif
+      
+      for(i=0,n=strlen(libs),k=0;i<n;i++) {
+	if (libs[i]==',') { k+=1; }
+      }
+      k+=1;
+      mz_dlopen_libraries=(char **) malloc(sizeof(char *)*(k+1));
+      mz_dlopen_libraries[0]=libs;
+      for(i=0,k=1,n=strlen(libs);i<n;i++) {
+	if (libs[i]==',') {
+	  libs[i]='\0';
+	  mz_dlopen_libraries[k++]=&libs[i+1];
+	  i+=1;
+	}
+      }
+      
+      if (mz_dynload_debug) {
+	fprintf(stderr,"k=%d\n",k);
+      }
+      mz_dlopen_libraries[k]=NULL;
+      
+      free(EP);
+    }
+  }
+
+  static void *mz_load_function(char *function)
+  {
+    int mz_dynload_debug=(1==0);
+    
+    {
+      char *dbg=getenv("MZ_DYNLOAD_DEBUG");
+      if (dbg!=NULL) {
+	mz_dynload_debug=atoi(dbg);
+      }
+    }
+
+    if (mz_dlopen_libraries==NULL) {
+      return NULL;
+    }
+    else {
+      if (mz_libraries==NULL) {
+        int i,n;
+        for(n=0;mz_dlopen_libraries[n]!=NULL;n++);
+	if (mz_dynload_debug) {
+	  fprintf(stderr,"SWIG:mzscheme:n=%d\n",n);
+	}
+        mz_libraries=(void **) malloc(sizeof(void*)*n);
+        for(i=0;i<n;i++) { 
+	  if (mz_dynload_debug) {
+	   fprintf(stderr,"SWIG:mzscheme:loading %s\n",mz_dlopen_libraries[i]);
+	  }
+#ifdef __OS_WIN32
+	  mz_libraries[i]=(void *) LoadLibrary(mz_dlopen_libraries[i]); 
+#else
+	  mz_libraries[i]=(void *) dlopen(mz_dlopen_libraries[i],RTLD_LAZY); 
+#endif
+	  if (mz_libraries[i]==NULL) {
+	    int k;
+	    char *libp;
+	    for(k=0;mz_dynload_libpaths[k]!=NULL && mz_libraries[i]==NULL;k++) {
+	      int L=strlen(mz_dynload_libpaths[k])+strlen("\\")+strlen(mz_dlopen_libraries[i])+1;
+	      libp=(char *) malloc(L*sizeof(char));
+	      sprintf(libp,"%s\\%s",mz_dynload_libpaths[k],mz_dlopen_libraries[i]);
+#ifdef __OS_WIN32
+	      mz_libraries[i]=(void *) LoadLibrary(libp); 
+#else
+	      mz_libraries[i]=(void *) dlopen(libp,RTLD_LAZY); 
+#endif
+	      if (mz_dynload_debug) {
+		fprintf(stderr,"SWIG:mzscheme:trying %s --> %p\n",libp,mz_libraries[i]);
+	      }
+	      free(libp);
+	    }
+	  }
+        }
+      }
+      {
+        int i;
+        void *func=NULL;
+
+        for(i=0;mz_dlopen_libraries[i]!=NULL && func==NULL;i++) {
+          if (mz_libraries[i]!=NULL) {
+#ifdef __OS_WIN32
+            func=GetProcAddress(mz_libraries[i],function);
+#else
+            func=dlsym(mz_libraries[i],function);
+#endif
+          }
+	  if (mz_dynload_debug) {
+	    fprintf(stderr,
+		    "SWIG:mzscheme:library:%s;dlopen=%p,function=%s,func=%p\n",
+		    mz_dlopen_libraries[i],mz_libraries[i],function,func
+		    );
+	  }
+        }
+
+        return func;
+      }
+    }
+  }
+
+/*** DLOPEN PATCH ******************************************************
+ * Contributed by Hans Oesterholt-Dijkema (jan. 2006)
+ ***********************************************************************/
+
 /* The interpreter will store a pointer to this structure in a global
    variable called swig-runtime-data-type-pointer.  The instance of this
    struct is only used if no other module has yet been loaded */
@@ -311,3 +504,4 @@ SWIG_MzScheme_SetModule(Scheme_Env *env, swig_module_info *module) {
 #ifdef __cplusplus
 }
 #endif
+