2001-10-14 Roland McGrath <roland@frob.com>

	* url.c: New file.
	(store_url_open): New function.
	(store_url_open_class): New const variable.
	* store.h: Declare them.
	* std.c (store_std_classes): Add &store_url_open_class to the list,
	move &store_nbd_class after it.

3 files changed, 129 insertions, 1 deletions

diff --git a/libstore/std.c b/libstore/std.c
index 4f82c380..90ddecd1 100644
--- a/libstore/std.c
+++ b/libstore/std.c
@@ -30,10 +30,15 @@ store_std_classes[] =
   &store_file_class,
   &store_zero_class,
   &store_task_class,
-  &store_nbd_class,
   &store_ileave_class, &store_concat_class, &store_remap_class,
   &store_query_class,
   &store_copy_class, &store_gunzip_class, &store_bunzip2_class,
+
+  /* This pseudo-class must appear before any real STORAGE_NETWORK class,
+     to parse STORAGE_NETWORK file_get_storage_info results properly.  */
+  &store_url_open_class,
+  &store_nbd_class,
+
   &store_typed_open_class,
   0
 };
diff --git a/libstore/store.h b/libstore/store.h
index a8ff49fe..0f13f96f 100644
--- a/libstore/store.h
+++ b/libstore/store.h
@@ -421,6 +421,13 @@ error_t store_typed_open (const char *name, int flags,
 			  const struct store_class *const *classes,
 			  struct store **store);
 
+/* Similar to store_typed_open, but NAME must be in URL format,
+   i.e. a class name followed by a ':' and any type-specific name.
+   A leading ':' or no ':' at all is invalid syntax.  */
+error_t store_url_open (const char *name, int flags,
+			const struct store_class *const *classes,
+			struct store **store);
+
 /* Return a new store in STORE that interleaves all the stores in STRIPES
    (NUM_STRIPES of them) every INTERLEAVE bytes; INTERLEAVE must be an
    integer multiple of each stripe's block size.  The stores in STRIPES are
@@ -526,6 +533,7 @@ extern const struct store_class store_copy_class;
 extern const struct store_class store_gunzip_class;
 extern const struct store_class store_bunzip2_class;
 extern const struct store_class store_typed_open_class;
+extern const struct store_class store_url_open_class;
 
 /* The following are not included in STORE_STD_CLASSES.  */
 extern const struct store_class store_mvol_class;
diff --git a/libstore/url.c b/libstore/url.c
new file mode 100644
index 00000000..967f1342
--- /dev/null
+++ b/libstore/url.c
@@ -0,0 +1,115 @@
+/* Support for opening stores named in URL syntax.
+
+   Copyright (C) 2001 Free Software Foundation, Inc.
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   The GNU Hurd is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
+
+#include "store.h"
+#include <string.h>
+#include <stdlib.h>
+
+static const struct store_class *
+find_url_class (const char *name, const struct store_class *const *classes)
+{
+  const struct store_class *const *cl;
+  const char *clname_end = strchr (name, ':');
+
+  if (clname_end == name || clname_end == 0)
+    return 0;
+
+  for (cl = classes ?: store_std_classes; *cl; cl++)
+    if (strlen ((*cl)->name) == (clname_end - name)
+	&& strncmp (name, (*cl)->name, (clname_end - name)) == 0)
+      return *cl;
+
+# pragma weak store_module_open_class
+  if (classes == 0 && store_module_open_class)
+    {
+      const struct store_class *cl;
+      if (store_module_open_class (name, &cl) == 0)
+	return cl;
+    }
+
+  return 0;
+}
+
+/* Similar to store_typed_open, but NAME must be in URL format,
+   i.e. a class name followed by a ':' and any type-specific name.
+   Store classes opened this way must strip off the "class:" prefix.
+   A leading ':' or no ':' at all is invalid syntax.  */
+
+error_t
+store_url_open (const char *name, int flags,
+		const struct store_class *const *classes,
+		struct store **store)
+{
+  const struct store_class *cl = find_url_class (name, classes);
+
+  if (cl == 0)
+    return EINVAL;
+
+  if (! cl->open)
+    /* CL cannot be opened.  */
+    return EOPNOTSUPP;
+
+  return (*cl->open) (name, flags, classes, store);
+}
+
+static error_t
+url_decode (struct store_enc *enc, const struct store_class *const *classes,
+	    struct store **store)
+{
+  const struct store_class *cl;
+
+  /* This is pretty bogus.  We use decode.c's code just to validate
+     the generic format and extract the name from the data.  */
+  struct store dummy, *dummyptr;
+  error_t dummy_create (mach_port_t port, int flags, size_t block_size,
+			const struct store_run *runs, size_t num_runs,
+			struct store **store)
+    {
+      *store = &dummy;
+      return 0;
+    }
+  error_t err = store_std_leaf_decode (enc, &dummy_create, &dummyptr);
+  if (err)
+    return err;
+
+  /* Find the class matching this name.  */
+  cl = find_url_class (dummy.name, classes);
+  free (dummy.name);
+  free (dummy.misc);
+
+  if (cl == 0)
+    return EINVAL;
+
+  /* Now that we have the class, we just punt to its own decode hook.  */
+
+  return (!cl->decode ? EOPNOTSUPP : (*cl->decode) (enc, classes, store));
+}
+
+/* This class is only trivially different from the "typed" class when used
+   by name.  Its real purpose is to decode file_get_storage_info results
+   that use the STORAGE_NETWORK type, for which the convention is that the
+   name be in URL format (i.e. "type:something").  */
+
+const struct store_class store_url_open_class =
+{
+  STORAGE_NETWORK, "url",
+  open: store_url_open,
+  decode: url_decode
+};