(struct store): Remove CLASS field. METHS field renamed CLASS.

(STORE_IMMUTABLE_FLAGS, STORE_GENERIC_FLAGS, STORE_BACKEND_SPEC_BASE,
  STORE_BACKEND_FLAGS, STORE_READONLY, STORE_HARD_READONLY, STORE_ENFORCED):
    New macros.
(struct store_class):
  Renamed from store_meths; all uses changed.
  Add ID, NAME, DECODE, SET_FLAGS, CLEAR_FLAGS, and NEXT fields.
(store_std_leaf_decode): Renamed from store_default_leaf_decode.
(store_std_leaf_create_t): New type.
(_STORE_STD_CLASS): New macro.
(struct store_argp_params): READONLY field deleted, FLAGS field added.
(store_allocate_child_encodings, store_encode_children, store_decode_children,
  store_set_flags, store_clear_flags, store_file_open, store_device_open,
  store_null_create, store_std_classes, _store_add_std_class,
  store_allocate_child_encodings, store_encode_children,
  store_decode_children): New declarations
(store_decode, store_create, store_device_create, _store_device_create,
  store_file_create, _store_file_create, store_ileave_create,
  store_concat_create, _make_store): Declarations updated.

1 files changed, 161 insertions, 69 deletions

diff --git a/libstore/store.h b/libstore/store.h
index 2186c259..84e8aae3 100644
--- a/libstore/store.h
+++ b/libstore/store.h
@@ -41,9 +41,6 @@ struct store
      our store.  */
   file_t source;
 
-  /* The type of storage this is (see STORAGE_ in hurd/hurd_types.h).  */
-  enum file_storage_class class;
-
   /* Address ranges in the underlying storage which make up our contiguous
      address space.  In units of BLOCK_SIZE, below.  */
   struct store_run *runs;	/* Malloced */
@@ -81,7 +78,7 @@ struct store
   void *misc;			/* malloced */
   size_t misc_len;
 
-  struct store_meths *meths;
+  struct store_class *class;
 
   /* A list of sub-stores.  The interpretation of this is type-specific.  */
   struct store **children;
@@ -89,6 +86,23 @@ struct store
 
   void *hook;			/* Type specific noise.  */
 };
+
+/* Store flags.  These are in addition to the STORAGE_ flags defined in
+   <hurd/hurd_types.h>.  XXX synchronize these values.  */
+
+/* Flags that reflect something immutable about the object.  */
+#define STORE_IMMUTABLE_FLAGS	0xFF
+
+/* Flags implemented by generic store code.  */
+#define STORE_READONLY		0x100	/* No writing allowed. */
+#define STORE_GENERIC_FLAGS	STORE_READONLY
+
+/* Flags implemented by each backend.  */
+#define STORE_HARD_READONLY	0x200	/* Can't be made writable.  */
+#define STORE_ENFORCED		0x400	/* Range is enforced by device.  */
+#define STORE_BACKEND_SPEC_BASE	0x1000 /* Here up are backend-specific */
+#define STORE_BACKEND_FLAGS	(STORE_HARD_READONLY | STORE_ENFORCED \
+				 | ~(STORE_BACKEND_SPEC_BASE - 1))
 
 typedef error_t (*store_write_meth_t)(struct store *store,
 				      off_t addr, size_t index,
@@ -101,8 +115,14 @@ typedef error_t (*store_read_meth_t)(struct store *store,
 
 struct store_enc;		/* fwd decl */
 
-struct store_meths
+struct store_class
 {
+  /* The type of storage this is (see STORAGE_ in hurd/hurd_types.h).  */
+  enum file_storage_class id;
+
+  /* Name of the class.  */
+  char *name;
+
   /* Read up to AMOUNT bytes at the underlying address ADDR from the storage
      into BUF and LEN.  INDEX varies from 0 to the number of runs in STORE. */
   store_read_meth_t read;
@@ -110,9 +130,6 @@ struct store_meths
      ADDR.  INDEX varies from 0 to the number of runs in STORE. */
   store_write_meth_t write;
 
-  /* Called just before deallocating STORE.  */
-  void (*cleanup) (struct store *store);
-
   /* To the lengths of each for the four arrays in ENC, add how much STORE
      would need to be encoded.  */
   error_t (*allocate_encoding)(const struct store *store,
@@ -120,61 +137,44 @@ struct store_meths
   /* Append the encoding for STORE to ENC.  */
   error_t (*encode) (const struct store *store, struct store_enc *enc);
 
+  /* Decode from ENC a new store, which return in STORE.  CLASSES is used to
+     lookup child classes.  */
+  error_t (*decode) (struct store_enc *enc, struct store_class *classes,
+		     struct store **store);
+
+  /* Modify flags that reflect backend state, such as STORE_HARD_READONLY and
+     STORE_ENFORCED.  */
+  error_t (*set_flags) (struct store *store, int flags);
+  error_t (*clear_flags) (struct store *store, int flags);
+
+  /* Called just before deallocating STORE.  */
+  void (*cleanup) (struct store *store);
+
   /* Copy any format-dependent fields in FROM to TO; if there's some reason
      why the copy can't be made, an error should be returned.  This call is
      made after all format-indendependent fields have been cloned.  */
   error_t (*clone) (const struct store *from, struct store *to);
+
+  /* For making a list of classes to pass to e.g. store_create.  */
+  struct store_class *next;
 };
 
 /* Return a new store in STORE, which refers to the storage underlying
-   SOURCE.  Consumes a send-right to SOURCE (which is simply stored
-   STORE->source; you can steal it back if you like (replacing it with
-   MACH_PORT_NULL, or destroy it with store_close_source).  */
-error_t store_create (file_t source, struct store **store);
-
-/* Return a new store in STORE referring to the mach device DEVICE.  Consumes
-   the send right DEVICE.  */
-error_t store_device_create (device_t device, struct store **store);
-
-/* Like store_device_create, but doesn't query the device for information.   */
-error_t _store_device_create (device_t device, size_t block_size,
-			      const struct store_run *runs, size_t num_runs,
-			      struct store **store);
-
-/* Return a new store in STORE referring to the file FILE.  Unlike
-   store_create, this will always use file i/o, even it would be possible to
-   be more direct.  This may work in more cases, for instance if the file has
-   holes.  Consumes the send right FILE.  */
-error_t store_file_create (file_t file, struct store **store);
-
-/* Like store_file_create, but doesn't query the file for information.  */
-error_t _store_file_create (file_t file, size_t block_size,
-			    const struct store_run *runs, size_t num_runs,
-			    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
-   consumed -- that is, will be freed when this store is (however, the
-   *array* STRIPES is copied, and so should be freed by the caller).  */
-error_t store_ileave_create (struct store * const *stripes, size_t num_stripes,
-			     off_t interleave, struct store **store);
-
-/* Return a new store in STORE that concatenates all the stores in STORES
-   (NUM_STORES of them).  The stores in STRIPES are consumed -- that is, will
-   be freed when this store is (however, the *array* STRIPES is copied, and
-   so should be freed by the caller).  */
-error_t store_concat_create (struct store * const *stores, size_t num_stores,
-			     struct store **store);
+   SOURCE.  CLASSES is used to select classes specified by the provider; if
+   it is 0, STORE_STD_CLASSES is used.  FLAGS is set with store_set_flags.  A
+   reference to SOURCE is created (but may be destroyed with
+   store_close_source).  */
+error_t store_create (file_t source, int flags, struct store_class *classes,
+		      struct store **store);
 
 void store_free (struct store *store);
 
-/* Allocate a new store structure of class CLASS, with meths METHS, and the
-   various other fields initialized to the given parameters.  */
+/* Allocate a new store structure with class CLASS, and the various other
+   fields initialized to the given parameters.  */
 struct store *
-_make_store (enum file_storage_class class, struct store_meths *meths,
-	     mach_port_t port, size_t block_size,
-	     const struct store_run *runs, size_t num_runs, off_t end);
+_make_store (struct store_class *class, mach_port_t port, int flags,
+	     size_t block_size, const struct store_run *runs, size_t num_runs,
+	     off_t end);
 
 /* Set STORE's current runs list to (a copy of) RUNS and NUM_RUNS.  */
 error_t store_set_runs (struct store *store,
@@ -188,6 +188,12 @@ error_t store_set_children (struct store *store,
 /* Sets the name associated with STORE to a copy of NAME.  */
 error_t store_set_name (struct store *store, const char *name);
 
+/* Add FLAGS to STORE's currently set flags.  */
+error_t store_set_flags (struct store *store, int flags);
+
+/* Remove FLAGS from STORE's currently set flags.  */
+error_t store_clear_flags (struct store *store, int flags);
+
 /* Fills in the values of the various fields in STORE that are derivable from
    the set of runs & the block size.  */
 void _store_derive (struct store *store);
@@ -232,6 +238,68 @@ error_t store_create_pager (struct store *store, vm_prot_t prot, ...,
 
 #endif
 
+/* Creating specific types of stores.  */
+
+/* Return a new store in STORE referring to the mach device DEVICE.  Consumes
+   the send right DEVICE.  */
+error_t store_device_create (device_t device, int flags, struct store **store);
+
+/* Like store_device_create, but doesn't query the device for information.   */
+error_t _store_device_create (device_t device, int flags, size_t block_size,
+			      const struct store_run *runs, size_t num_runs,
+			      struct store **store);
+
+/* Open the device NAME, and return the corresponding store in STORE.  */
+error_t store_device_open (const char *name, int flags, struct store **store);
+
+/* Return a new store in STORE referring to the file FILE.  Unlike
+   store_create, this will always use file i/o, even it would be possible to
+   be more direct.  This may work in more cases, for instance if the file has
+   holes.  Consumes the send right FILE.  */
+error_t store_file_create (file_t file, int flags, struct store **store);
+
+/* Like store_file_create, but doesn't query the file for information.  */
+error_t _store_file_create (file_t file, int flags, size_t block_size,
+			    const struct store_run *runs, size_t num_runs,
+			    struct store **store);
+
+/* Open the file NAME, and return the corresponding store in STORE.  */
+error_t store_file_open (const char *name, int flags, 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
+   consumed -- that is, will be freed when this store is (however, the
+   *array* STRIPES is copied, and so should be freed by the caller).  */
+error_t store_ileave_create (struct store * const *stripes, size_t num_stripes,
+			     off_t interleave, int flags, struct store **store);
+
+/* Return a new store in STORE that concatenates all the stores in STORES
+   (NUM_STORES of them).  The stores in STRIPES are consumed -- that is, will
+   be freed when this store is (however, the *array* STRIPES is copied, and
+   so should be freed by the caller).  */
+error_t store_concat_create (struct store * const *stores, size_t num_stores,
+			     int flags, struct store **store);
+
+/* Return a new null store SIZE bytes long in STORE.  */
+error_t store_null_create (size_t size, int flags, struct store **store);
+
+/* Standard store classes implemented by libstore.  */
+extern struct store_class *store_std_classes;
+
+/* Add CLASS to the list of standard classes.  It must not already be in the
+   list, or in any other, as its next field is simply written over.  */
+void _store_add_std_class (struct store_class *class);
+
+/* Use this macro to automagically add a class to STORE_STD_CLASSES at
+   startup.  */
+#define _STORE_STD_CLASS(class_struct)					    \
+static void _store_init_std_##class_struct () __attribute__ ((constructor));\
+static void _store_init_std_##class_struct ()				    \
+{									    \
+  _store_add_std_class (&class_struct);					    \
+}
+
 /* Used to hold the various bits that make up the representation of a store
    for transmission via rpc.  See <hurd/hurd_types.h> for an explanation of
    the encodings for the various storage types.  */
@@ -278,25 +346,49 @@ void store_enc_dealloc (struct store_enc *enc);
    used by the unsent vectors.  */
 error_t store_encode (const struct store *store, struct store_enc *enc);
 
-/* Decode ENC, either returning a new store in STORE, or an error.  If
-   nothing else is to be done with ENC, its contents may then be freed using
-   store_enc_dealloc.  */
-error_t store_decode (struct store_enc *enc, struct store **store);
+/* Decode ENC, either returning a new store in STORE, or an error.  CLASSES
+   defines the mapping from hurd storage class ids to store classes; if it is
+   0, STORE_STD_CLASSES is used.  If nothing else is to be done with ENC, its
+   contents may then be freed using store_enc_dealloc.  */
+error_t store_decode (struct store_enc *enc, struct store_class *classes,
+		      struct store **store);
+
+/* Calls the allocate_encoding method in each child store of STORE,
+   propagating any errors.  If any child does not hae such a method,
+   EOPNOTSUPP is returned.  */
+error_t store_allocate_child_encodings (const struct store *store,
+					struct store_enc *enc);
+
+/* Calls the encode method in each child store of STORE, propagating any
+   errors.  If any child does not hae such a method, EOPNOTSUPP is returned. */
+error_t store_encode_children (const struct store *store,
+			       struct store_enc *enc);
+
+/* Decodes NUM_CHILDREN from ENC, storing the results into successive
+   positions in CHILDREN.  */
+error_t store_decode_children (struct store_enc *enc, int num_children,
+			       struct store_class *classes,
+			       struct store **children);
 
-/* Default encoding used for most leaf store types.  */
-error_t store_default_leaf_allocate_encoding (struct store *store,
-					      struct store_enc *enc);
-error_t store_default_leaf_encode (struct store *store, struct store_enc *enc);
+/* Standard encoding used for most leaf store types.  */
+error_t store_std_leaf_allocate_encoding (const struct store *store,
+					  struct store_enc *enc);
+error_t store_std_leaf_encode (const struct store *store,
+			       struct store_enc *enc);
+
+/* Creation function signature used by store_std_leaf_decode.  */
+typedef error_t (*store_std_leaf_create_t)(mach_port_t port,
+					   int flags,
+					   size_t block_size,
+					   const struct store_run *runs,
+					   size_t num_runs,
+					   struct store **store);
 
 /* Decodes the standard leaf encoding that's common to various builtin
    formats, and calls CREATE to actually create the store.  */
-error_t store_default_leaf_decode (struct store_enc *enc,
-				   error_t (*create)(mach_port_t port,
-						     size_t block_size,
-						     const struct store_run *runs,
-						     size_t num_runs,
-						     struct store **store),
-				   struct store **store);
+error_t store_std_leaf_decode (struct store_enc *enc,
+			       store_std_leaf_create_t create,
+			       struct store **store);
 
 /* An argument parser that may be used for parsing a simple command line
    specification for stores.  The accompanying input parameter must be a
@@ -307,8 +399,8 @@ extern struct argp store_argp;
    STORE_ARGP.  */
 struct store_argp_params
 {
-  /* If true, open the underlying file/device readonly.  */
-  int readonly : 1;
+  /* An initial set of flags desired to be set.  */
+  int flags;
 
   /* If true, don't attempt use store_file_create to create a store on files
      upon which store_create has failed.  */