Substantial changes for new module system.

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@908 626c5289-ae23-0410-ae9c-e8d60b6d4f22

SWIG/Source/Swig/module.c

@@ -0,0 +1,166 @@
+/* ----------------------------------------------------------------------------- 
+ * module.c
+ *
+ *     This file implements the SWIG module system.  Modules are simply 
+ *     pieces of code that manipulate tree objects.  Each module is defined
+ *     by 4 quantities:
+ *  
+ *            -  Module name    (used to select the module on the command line)
+ *            -  init function  (called with the SWIG command line options).
+ *            -  start function (called to launch the module)
+ *            -  start tag      (starting tag expected by the module)
+ * 
+ *     Currently modules must be statically linked with SWIG.  However, it
+ *     is anticipated that the module system may eventually support
+ *     dynamic loading.
+ *
+ * Author(s) : David Beazley (beazley@cs.uchicago.edu)
+ *
+ * Copyright (C) 1999-2000.  The University of Chicago
+ * See the file LICENSE for information on usage and redistribution.	
+ * ----------------------------------------------------------------------------- */
+
+#include "swig.h"
+
+static char cvsroot[] = "$Header$";
+
+struct Module {
+  String   *modname;
+  int      (*initfunc)(int argc, char **argv);
+  DOH      *(*startfunc)(DOH *);
+  String   *starttag;
+  struct Module *next;
+};
+
+static Module *Modules = 0;
+static Hash   *LoadedModules = 0;
+
+/* -----------------------------------------------------------------------------
+ * Swig_register_module()
+ *
+ * Register a new module with the system
+ * ----------------------------------------------------------------------------- */
+
+void
+Swig_register_module(const String_or_char *modname, const String_or_char *starttag,
+		     int (*initfunc)(int argc, char **argv),
+		     DOH *(*startfunc)(DOH *))
+{
+  Module *m;
+  m = (Module *) malloc(sizeof(Module));
+  m->modname = NewString(modname);
+  m->starttag = NewString(starttag);
+  m->initfunc = initfunc;
+  m->startfunc = startfunc;
+  m->next = Modules;
+  Modules = m;
+}
+
+/* ----------------------------------------------------------------------------- 
+ * Swig_load_module()
+ *
+ * Load a module.  Returns the module object.
+ * ----------------------------------------------------------------------------- */
+
+Module *
+Swig_load_module(const String_or_char *modname) {
+  Module *m;
+  m = Modules;
+  while (m) {
+    if (Cmp(m->modname, modname) == 0) {
+      /* Create a new entry in the loaded modules table */
+      List *ml;
+      if (!LoadedModules) LoadedModules = NewHash();
+      ml = Getattr(LoadedModules,m->starttag);
+      if (!ml) {
+	ml = NewList();
+	Setattr(LoadedModules,m->starttag,ml);
+      }
+      Append(ml,NewVoid(m,0));
+      return m;
+    }
+    m = m->next;
+  }
+  return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * Swig_init_module()
+ * 
+ * Initialize a module
+ * ----------------------------------------------------------------------------- */
+
+int Swig_init_module(Module *m, int argc, char **argv) {
+  return (*m->initfunc)(argc,argv);
+}
+
+/* -----------------------------------------------------------------------------
+ * Swig_start_module()
+ *
+ * Start a module
+ * ----------------------------------------------------------------------------- */
+
+DOH *
+Swig_start_module(Module *m, DOH *obj) {
+  return (*m->startfunc)(obj);
+}
+
+/* -----------------------------------------------------------------------------
+ * Swig_run_modules()
+ *
+ * Given a tree node. This function tries to run it through all of the loaded
+ * modules.  This works by looking at the "tag" attribute of the node and
+ * searching for a loaded module that can handle that tag.  If no module can be
+ * found, processing stops and an error is generated.
+ *
+ * If more than one module can work on a given tag, those modules will be
+ * executed one after the other.  Caveat: if one of those modules outputs
+ * a different type of tree, processing immediately stops.
+ * ----------------------------------------------------------------------------- */
+
+DOH *Swig_run_modules(DOH *node) {
+  String *tag;
+  List   *ml;
+  DOH    *newnode;
+  String *newtag;
+  int     i;
+
+  tag = Getattr(node,"tag");
+  if (!tag) {
+    Printf(stderr,"Whoa.  No tag attribute on node passed to Swig_module_run.\n");
+    exit(EXIT_FAILURE);
+  }
+  /* Get the set of modules that can respond to this node */
+  while (node) {
+    if (!LoadedModules) {
+      Printf(stderr,"No modules loaded.\n");
+      return 0;
+    }
+    ml = Getattr(LoadedModules,tag);
+    if ((!ml) || (Len(ml) == 0)) {
+      Printf(stderr,"No module for object '%s'\n", tag);
+      return 0;
+    }
+    newnode = 0;
+    newtag = 0;
+    for (i = 0; i < Len(ml); i++) {
+      Module *m;
+      m = (Module *) Data(Getitem(ml,i));
+      assert(m);
+      newnode = (*m->startfunc)(node);
+      if (!newnode) return 0;   /* Done */
+      newtag = Getattr(newnode,"tag");
+      if (!newtag) {
+	Printf(stderr,"Fatal error. Module '%s' returns untagged object.\n", m->modname);
+	exit(EXIT_FAILURE);
+      }
+      if (Cmp(newtag,tag)) break;      /* Tag is different.  Oh well */
+    }
+    if (Cmp(newtag,tag) == 0) break;   /* Hmmm. The tag is the same but we already did everything */
+    node = newnode;
+    tag = newtag;
+  }
+  return 0;
+}
+ 
+