/* PSPP - a program for statistical analysis.
- Copyright (C) 1997-9, 2000, 2006 Free Software Foundation, Inc.
+ Copyright (C) 1997-9, 2000, 2006, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#include <config.h>
-#include "file-handle-def.h"
+#include "data/file-handle-def.h"
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
-#include <libpspp/alloc.h>
-#include <libpspp/compiler.h>
-#include <libpspp/magic.h>
-#include <libpspp/message.h>
-#include <libpspp/str.h>
-#include <data/file-name.h>
-#include <data/variable.h>
-#include <data/scratch-handle.h>
+#include "data/dataset.h"
+#include "data/variable.h"
+#include "libpspp/assertion.h"
+#include "libpspp/cast.h"
+#include "libpspp/compiler.h"
+#include "libpspp/hash-functions.h"
+#include "libpspp/hmap.h"
+#include "libpspp/i18n.h"
+#include "libpspp/message.h"
+#include "libpspp/str.h"
+
+#include <sys/stat.h>
+
+#include "gl/dirname.h"
+#include "gl/xalloc.h"
#include "gettext.h"
#define _(msgid) gettext (msgid)
-/* (headers) */
+#if defined _WIN32 || defined __WIN32__
+#define WIN32_LEAN_AND_MEAN /* avoid including junk */
+#include <windows.h>
+#endif
/* File handle. */
struct file_handle
{
- struct file_handle *next; /* Next in global list. */
- int open_cnt; /* 0=not open, otherwise # of openers. */
- bool deleted; /* Destroy handle when open_cnt goes to 0? */
-
- char id[LONG_NAME_LEN + 1]; /* Identifier token; empty string if none. */
+ struct hmap_node name_node; /* Element in named_handles hmap. */
+ size_t ref_cnt; /* Number of references. */
+ char *id; /* Identifier token, NULL if none. */
char *name; /* User-friendly identifying name. */
- const char *type; /* If open, type of file. */
- char open_mode[3]; /* "[rw][se]". */
- void *aux; /* Aux data pointer for owner if any. */
enum fh_referent referent; /* What the file handle refers to. */
/* FH_REF_FILE only. */
char *file_name; /* File name as provided by user. */
- struct file_identity *identity; /* For checking file identity. */
+ char *file_name_encoding; /* The character encoding of file_name,
+ This is NOT the encoding of the file contents! */
enum fh_mode mode; /* File mode. */
+ enum fh_line_ends line_ends; /* Line ends for text files. */
/* FH_REF_FILE and FH_REF_INLINE only. */
size_t record_width; /* Length of fixed-format records. */
size_t tab_width; /* Tab width, 0=do not expand tabs. */
+ char *encoding; /* Charset for contents. */
- /* FH_REF_SCRATCH only. */
- struct scratch_handle *sh; /* Scratch file data. */
+ /* FH_REF_DATASET only. */
+ struct dataset *ds; /* Dataset. */
};
-/* List of all handles. */
-static struct file_handle *file_handles;
+/* All "struct file_handle"s with nonnull 'id' member. */
+static struct hmap named_handles = HMAP_INITIALIZER (named_handles);
/* Default file handle for DATA LIST, REREAD, REPEATING DATA
commands. */
static struct file_handle *inline_file;
static struct file_handle *create_handle (const char *id,
- const char *name, enum fh_referent);
+ char *name, enum fh_referent,
+ const char *encoding);
+static void free_handle (struct file_handle *);
+static void unname_handle (struct file_handle *);
+
+/* Hash table of all active locks. */
+static struct hmap locks = HMAP_INITIALIZER (locks);
+
+static struct file_identity *fh_get_identity (const struct file_handle *);
+static void fh_free_identity (struct file_identity *);
+static int fh_compare_file_identities (const struct file_identity *,
+ const struct file_identity *);
+static unsigned int fh_hash_identity (const struct file_identity *);
/* File handle initialization routine. */
void
fh_init (void)
{
- inline_file = create_handle ("INLINE", "INLINE", FH_REF_INLINE);
+ inline_file = create_handle ("INLINE", xstrdup ("INLINE"), FH_REF_INLINE,
+ "Auto");
inline_file->record_width = 80;
inline_file->tab_width = 8;
}
+/* Removes all named file handles from the global list. */
+void
+fh_done (void)
+{
+ struct file_handle *handle, *next;
+
+ HMAP_FOR_EACH_SAFE (handle, next,
+ struct file_handle, name_node, &named_handles)
+ unname_handle (handle);
+
+ free_handle (inline_file);
+}
+
/* Free HANDLE and remove it from the global list. */
static void
free_handle (struct file_handle *handle)
{
+ if (handle == NULL)
+ return;
+
/* Remove handle from global list. */
- if (file_handles == handle)
- file_handles = handle->next;
- else
- {
- struct file_handle *iter = file_handles;
- while (iter->next != handle)
- iter = iter->next;
- iter->next = handle->next;
- }
+ if (handle->id != NULL)
+ hmap_delete (&named_handles, &handle->name_node);
/* Free data. */
+ free (handle->id);
free (handle->name);
free (handle->file_name);
- fn_free_identity (handle->identity);
- scratch_handle_destroy (handle->sh);
+ free (handle->file_name_encoding);
+ free (handle->encoding);
free (handle);
}
-/* Frees all the file handles. */
-void
-fh_done (void)
+/* Make HANDLE unnamed, so that it can no longer be referenced by
+ name. The caller must hold a reference to HANDLE, which is
+ not affected by this function. */
+static void
+unname_handle (struct file_handle *handle)
{
- while (file_handles != NULL)
- free_handle (file_handles);
+ assert (handle->id != NULL);
+ free (handle->id);
+ handle->id = NULL;
+ hmap_delete (&named_handles, &handle->name_node);
+
+ /* Drop the reference held by the named_handles table. */
+ fh_unref (handle);
}
-/* Returns the handle with the given ID, or a null pointer if
- there is none. */
+/* Increments HANDLE's reference count and returns HANDLE. */
struct file_handle *
-fh_from_id (const char *id)
+fh_ref (struct file_handle *handle)
{
- struct file_handle *iter;
-
- for (iter = file_handles; iter != NULL; iter = iter->next)
- if (!iter->deleted && !strcasecmp (id, iter->id))
- return iter;
- return NULL;
+ if (handle == fh_inline_file ())
+ return handle;
+ assert (handle->ref_cnt > 0);
+ handle->ref_cnt++;
+ return handle;
}
-/* Returns the handle for the file named FILE_NAME,
- or a null pointer if none exists.
- Different names for the same file (e.g. "x" and "./x") are
- considered equivalent. */
-struct file_handle *
-fh_from_file_name (const char *file_name)
+/* Decrements HANDLE's reference count.
+ If the reference count drops to 0, HANDLE is destroyed. */
+void
+fh_unref (struct file_handle *handle)
{
- struct file_identity *identity;
- struct file_handle *iter;
-
- /* First check for a file with the same identity. */
- identity = fn_get_identity (file_name);
- if (identity != NULL)
+ if (handle != NULL)
{
- for (iter = file_handles; iter != NULL; iter = iter->next)
- if (!iter->deleted
- && iter->referent == FH_REF_FILE
- && iter->identity != NULL
- && !fn_compare_file_identities (identity, iter->identity))
- {
- fn_free_identity (identity);
- return iter;
- }
- fn_free_identity (identity);
+ if (handle == fh_inline_file ())
+ return;
+ assert (handle->ref_cnt > 0);
+ if (--handle->ref_cnt == 0)
+ free_handle (handle);
}
+}
+
+/* Make HANDLE unnamed, so that it can no longer be referenced by
+ name. The caller must hold a reference to HANDLE, which is
+ not affected by this function.
+
+ This function ignores a null pointer as input. It has no
+ effect on the inline handle, which is always named INLINE.*/
+void
+fh_unname (struct file_handle *handle)
+{
+ assert (handle->ref_cnt > 1);
+ if (handle != fh_inline_file () && handle->id != NULL)
+ unname_handle (handle);
+}
+
+/* Returns the handle with the given ID, or a null pointer if
+ there is none. */
+struct file_handle *
+fh_from_id (const char *id)
+{
+ struct file_handle *handle;
- /* Then check for a file with the same name. */
- for (iter = file_handles; iter != NULL; iter = iter->next)
- if (!iter->deleted
- && iter->referent == FH_REF_FILE && !strcmp (file_name, iter->file_name))
- return iter;
+ HMAP_FOR_EACH_WITH_HASH (handle, struct file_handle, name_node,
+ utf8_hash_case_string (id, 0), &named_handles)
+ if (!utf8_strcasecmp (id, handle->id))
+ {
+ return fh_ref (handle);
+ }
return NULL;
}
The new handle is not fully initialized. The caller is
responsible for completing its initialization. */
static struct file_handle *
-create_handle (const char *id, const char *handle_name,
- enum fh_referent referent)
-{
- struct file_handle *handle = xzalloc (sizeof *handle);
- assert (id == NULL || fh_from_id (id) == NULL);
- handle->next = file_handles;
- handle->open_cnt = 0;
- handle->deleted = false;
- str_copy_trunc (handle->id, sizeof handle->id, id != NULL ? id : "");
- handle->name = xstrdup (handle_name);
- handle->type = NULL;
- handle->aux = NULL;
+create_handle (const char *id, char *handle_name, enum fh_referent referent,
+ const char *encoding)
+{
+ struct file_handle *handle = XZALLOC (struct file_handle);
+
+ handle->ref_cnt = 1;
+ handle->id = xstrdup_if_nonnull (id);
+ handle->name = handle_name;
handle->referent = referent;
- file_handles = handle;
+ handle->encoding = xstrdup (encoding);
+
+ if (id != NULL)
+ {
+ hmap_insert (&named_handles, &handle->name_node,
+ utf8_hash_case_string (handle->id, 0));
+ }
+
return handle;
}
return inline_file;
}
-/* Creates a new file handle with the given ID, which may be
- null. If it is non-null, it must be unique among existing
- file identifiers. The new handle is associated with file
- FILE_NAME and the given PROPERTIES. */
+/* Creates and returns a new file handle with the given ID, which may be null.
+ If it is non-null, it must be a UTF-8 encoded string that is unique among
+ existing file identifiers. The new handle is associated with file FILE_NAME
+ and the given PROPERTIES. */
struct file_handle *
-fh_create_file (const char *id, const char *file_name,
+fh_create_file (const char *id, const char *file_name, const char *file_name_encoding,
const struct fh_properties *properties)
{
char *handle_name;
struct file_handle *handle;
- handle_name = id != NULL ? (char *) id : xasprintf ("\"%s\"", file_name);
- handle = create_handle (id, handle_name, FH_REF_FILE);
- if (id == NULL)
- free (handle_name);
+ handle_name = id != NULL ? xstrdup (id) : xasprintf ("`%s'", file_name);
+ handle = create_handle (id, handle_name, FH_REF_FILE, properties->encoding);
handle->file_name = xstrdup (file_name);
- handle->identity = fn_get_identity (file_name);
+ handle->file_name_encoding = xstrdup_if_nonnull (file_name_encoding);
handle->mode = properties->mode;
+ handle->line_ends = properties->line_ends;
handle->record_width = properties->record_width;
handle->tab_width = properties->tab_width;
return handle;
/* Creates a new file handle with the given ID, which must be
unique among existing file identifiers. The new handle is
- associated with a scratch file (initially empty). */
+ associated with a dataset file (initially empty). */
struct file_handle *
-fh_create_scratch (const char *id)
+fh_create_dataset (struct dataset *ds)
{
+ const char *name;
struct file_handle *handle;
- assert (id != NULL);
- handle = create_handle (id, id, FH_REF_SCRATCH);
- handle->sh = NULL;
+
+ name = dataset_name (ds);
+ if (name[0] == '\0')
+ name = _("active dataset");
+
+ handle = create_handle (NULL, xstrdup (name), FH_REF_DATASET, C_ENCODING);
+ handle->ds = ds;
return handle;
}
const struct fh_properties *
fh_default_properties (void)
{
+#if defined _WIN32 || defined __WIN32__
+#define DEFAULT_LINE_ENDS FH_END_CRLF
+#else
+#define DEFAULT_LINE_ENDS FH_END_LF
+#endif
+
static const struct fh_properties default_properties
- = {FH_MODE_TEXT, 1024, 4};
+ = {FH_MODE_TEXT, DEFAULT_LINE_ENDS, 1024, 4, (char *) "Auto"};
return &default_properties;
}
-/* Deletes FH from the global list of file handles. Afterward,
- attempts to search for it will fail. Unless the file handle
- is currently open, it will be destroyed; otherwise, it will be
- destroyed later when it is closed.
- Normally needed only if a file_handle needs to be re-assigned.
- Otherwise, just let fh_done() destroy the handle. */
-void
-fh_free (struct file_handle *handle)
-{
- if (handle == fh_inline_file () || handle == NULL || handle->deleted)
- return;
- handle->deleted = true;
-
- if (handle == default_handle)
- default_handle = fh_inline_file ();
-
- if (handle->open_cnt == 0)
- free_handle (handle);
-}
-
-/* Returns an English description of MODE,
- which is in the format of the MODE argument to fh_open(). */
-static const char *
-mode_name (const char *mode)
-{
- assert (mode != NULL);
- assert (mode[0] == 'r' || mode[0] == 'w');
-
- return mode[0] == 'r' ? "reading" : "writing";
-}
-
-/* Tries to open handle H with the given TYPE and MODE.
-
- H's referent type must be one of the bits in MASK. The caller
- must verify this ahead of time; we simply assert it here.
-
- TYPE is the sort of file, e.g. "system file". Only one given
- type of access is allowed on a given file handle at once.
- If successful, a reference to TYPE is retained, so it should
- probably be a string literal.
-
- MODE combines the read or write mode with the sharing mode.
- The first character is 'r' for read, 'w' for write. The
- second character is 's' to permit sharing, 'e' to require
- exclusive access.
-
- Returns the address of a void * that the caller can use for
- data specific to the file handle if successful, or a null
- pointer on failure. For exclusive access modes the void *
- will always be a null pointer at return. In shared access
- modes the void * will necessarily be null only if no other
- sharers are active. */
-void **
-fh_open (struct file_handle *h, enum fh_referent mask UNUSED,
- const char *type, const char *mode)
-{
- assert (h != NULL);
- assert ((fh_get_referent (h) & mask) != 0);
- assert (type != NULL);
- assert (mode != NULL);
- assert (mode[0] == 'r' || mode[0] == 'w');
- assert (mode[1] == 's' || mode[1] == 'e');
- assert (mode[2] == '\0');
-
- if (h->open_cnt != 0)
- {
- if (strcmp (h->type, type))
- {
- msg (SE, _("Can't open %s as a %s because it is "
- "already open as a %s."),
- fh_get_name (h), type, h->type);
- return NULL;
- }
- else if (strcmp (h->open_mode, mode))
- {
- msg (SE, _("Can't open %s as a %s for %s because it is "
- "already open for %s."),
- fh_get_name (h), type, mode_name (mode),
- mode_name (h->open_mode));
- return NULL;
- }
- else if (h->open_mode[1] == 'e')
- {
- msg (SE, _("Can't re-open %s as a %s for %s."),
- fh_get_name (h), type, mode_name (mode));
- return NULL;
- }
- }
- else
- {
- h->type = type;
- strcpy (h->open_mode, mode);
- assert (h->aux == NULL);
- }
- h->open_cnt++;
-
- return &h->aux;
-}
-
-/* Closes file handle H, which must have been open for the
- specified TYPE and MODE of access provided to fh_open().
- Returns zero if the file is now closed, nonzero if it is still
- open due to another reference.
-
- After fh_close() returns zero for a handle, it is unsafe to
- reference that file handle again in any way, because its
- storage may have been freed. */
-int
-fh_close (struct file_handle *h, const char *type, const char *mode)
-{
- assert (h != NULL);
- assert (h->open_cnt > 0);
- assert (type != NULL);
- assert (!strcmp (type, h->type));
- assert (mode != NULL);
- assert (!strcmp (mode, h->open_mode));
-
- if (--h->open_cnt == 0)
- {
- h->type = NULL;
- h->aux = NULL;
- if (h->deleted)
- free_handle (h);
- return 0;
- }
- return 1;
-}
-
-/* Is the file open? BEGIN DATA...END DATA uses this to detect
- whether the inline file is actually in use. */
-bool
-fh_is_open (const struct file_handle *handle)
-{
- return handle->open_cnt > 0;
-}
-
/* Returns the identifier that may be used in syntax to name the
given HANDLE, which takes the form of a PSPP identifier. If
HANDLE has no identifier, returns a null pointer.
const char *
fh_get_id (const struct file_handle *handle)
{
- return handle->id[0] != '\0' ? handle->id : NULL;
+ return handle->id;
}
/* Returns a user-friendly string to identify the given HANDLE.
return handle->file_name;
}
+
+/* Returns the character encoding of the name of the file associated with HANDLE. */
+const char *
+fh_get_file_name_encoding (const struct file_handle *handle)
+{
+ assert (handle->referent == FH_REF_FILE);
+ return handle->file_name_encoding;
+}
+
+
/* Returns the mode of HANDLE. */
enum fh_mode
fh_get_mode (const struct file_handle *handle)
return handle->mode;
}
+/* Returns the line ends of HANDLE, which must be a handle associated with a
+ file. */
+enum fh_line_ends
+fh_get_line_ends (const struct file_handle *handle)
+{
+ assert (handle->referent == FH_REF_FILE);
+ return handle->line_ends;
+}
+
/* Returns the width of a logical record on HANDLE. */
size_t
fh_get_record_width (const struct file_handle *handle)
return handle->tab_width;
}
-/* Returns the scratch file handle associated with HANDLE.
- Applicable to only FH_REF_SCRATCH files. */
-struct scratch_handle *
-fh_get_scratch_handle (struct file_handle *handle)
+/* Returns the encoding of characters read from HANDLE. */
+const char *
+fh_get_encoding (const struct file_handle *handle)
{
- assert (handle->referent == FH_REF_SCRATCH);
- return handle->sh;
+ return handle->encoding;
}
-/* Sets SH to be the scratch file handle associated with HANDLE.
- Applicable to only FH_REF_SCRATCH files. */
-void
-fh_set_scratch_handle (struct file_handle *handle, struct scratch_handle *sh)
+/* Returns true if A and B refer to the same file or dataset, false
+ otherwise. */
+bool
+fh_equal (const struct file_handle *a, const struct file_handle *b)
{
- assert (handle->referent == FH_REF_SCRATCH);
- handle->sh = sh;
+ if (a->referent != b->referent)
+ return false;
+
+ switch (a->referent)
+ {
+ case FH_REF_FILE:
+ {
+ struct file_identity *a_id = fh_get_identity (a);
+ struct file_identity *b_id = fh_get_identity (b);
+
+ int cmp = fh_compare_file_identities (a_id, b_id);
+
+ fh_free_identity (a_id);
+ fh_free_identity (b_id);
+
+ return cmp == 0;
+ }
+
+ case FH_REF_INLINE:
+ return true;
+
+ case FH_REF_DATASET:
+ return a->ds == b->ds;
+
+ default:
+ NOT_REACHED ();
+ }
+}
+
+/* Returns the dataset handle associated with HANDLE.
+ Applicable to only FH_REF_DATASET files. */
+struct dataset *
+fh_get_dataset (const struct file_handle *handle)
+{
+ assert (handle->referent == FH_REF_DATASET);
+ return handle->ds;
}
/* Returns the current default handle. */
{
assert (new_default_handle == NULL
|| (new_default_handle->referent & (FH_REF_INLINE | FH_REF_FILE)));
+ if (default_handle != NULL && default_handle != inline_file)
+ fh_unref (default_handle);
default_handle = new_default_handle;
+ if (default_handle != NULL)
+ default_handle = fh_ref (default_handle);
+}
+\f
+/* Information about a file handle's readers or writers. */
+struct fh_lock
+ {
+ struct hmap_node node; /* hmap_node member. */
+
+ /* Hash key. */
+ enum fh_referent referent; /* Type of underlying file. */
+ union
+ {
+ struct file_identity *file; /* FH_REF_FILE only. */
+ unsigned int unique_id; /* FH_REF_DATASET only. */
+ }
+ u;
+ enum fh_access access; /* Type of file access. */
+
+ /* Number of openers. */
+ size_t open_cnt;
+
+ /* Applicable only when open_cnt > 0. */
+ bool exclusive; /* No other openers allowed? */
+ const char *type; /* Human-readable type of file. */
+ void *aux; /* Owner's auxiliary data. */
+ };
+
+
+static void make_key (struct fh_lock *, const struct file_handle *,
+ enum fh_access);
+static void free_key (struct fh_lock *);
+static int compare_fh_locks (const struct fh_lock *a, const struct fh_lock *b);
+static unsigned int hash_fh_lock (const struct fh_lock *lock);
+
+/* Tries to lock handle H for the given kind of ACCESS and TYPE
+ of file. Returns a pointer to a struct fh_lock if successful,
+ otherwise a null pointer.
+
+ H's referent type must be one of the bits in MASK. The caller
+ must verify this ahead of time; we simply assert it here.
+
+ TYPE is the sort of file, e.g. "system file". Only one type
+ of access is allowed on a given file at a time for reading,
+ and similarly for writing. If successful, a reference to TYPE
+ is retained, so it should probably be a string literal.
+
+ TYPE should be marked with N_() in the caller: that is, the
+ caller should not translate it with gettext, but fh_lock will
+ do so.
+
+ ACCESS specifies whether the lock is for reading or writing.
+ EXCLUSIVE is true to require exclusive access, false to allow
+ sharing with other accessors. Exclusive read access precludes
+ other readers, but not writers; exclusive write access
+ precludes other writers, but not readers. A sharable read or
+ write lock precludes reader or writers, respectively, of a
+ different TYPE.
+
+ A lock may be associated with auxiliary data. See
+ fh_lock_get_aux and fh_lock_set_aux for more details. */
+struct fh_lock *
+fh_lock (struct file_handle *h, enum fh_referent mask UNUSED,
+ const char *type, enum fh_access access, bool exclusive)
+{
+ struct fh_lock *key = NULL;
+ size_t hash ;
+ struct fh_lock *lock = NULL;
+ bool found_lock = false;
+
+ assert ((fh_get_referent (h) & mask) != 0);
+ assert (access == FH_ACC_READ || access == FH_ACC_WRITE);
+
+ key = xmalloc (sizeof *key);
+
+ make_key (key, h, access);
+
+ key->open_cnt = 1;
+ key->exclusive = exclusive;
+ key->type = type;
+ key->aux = NULL;
+
+ hash = hash_fh_lock (key);
+
+ HMAP_FOR_EACH_WITH_HASH (lock, struct fh_lock, node, hash, &locks)
+ {
+ if (0 == compare_fh_locks (lock, key))
+ {
+ found_lock = true;
+ break;
+ }
+ }
+
+ if (found_lock)
+ {
+ if (strcmp (lock->type, type))
+ {
+ if (access == FH_ACC_READ)
+ msg (SE, _("Can't read from %s as a %s because it is "
+ "already being read as a %s."),
+ fh_get_name (h), gettext (type), gettext (lock->type));
+ else
+ msg (SE, _("Can't write to %s as a %s because it is "
+ "already being written as a %s."),
+ fh_get_name (h), gettext (type), gettext (lock->type));
+ return NULL;
+ }
+ else if (exclusive || lock->exclusive)
+ {
+ msg (SE, _("Can't re-open %s as a %s."),
+ fh_get_name (h), gettext (type));
+ return NULL;
+ }
+ lock->open_cnt++;
+
+ free_key (key);
+ free (key);
+
+ return lock;
+ }
+
+ hmap_insert (&locks, &key->node, hash);
+ found_lock = false;
+ HMAP_FOR_EACH_WITH_HASH (lock, struct fh_lock, node, hash, &locks)
+ {
+ if (0 == compare_fh_locks (lock, key))
+ {
+ found_lock = true;
+ break;
+ }
+ }
+
+ assert (found_lock);
+
+ return key;
+}
+
+/* Releases LOCK that was acquired with fh_lock.
+ Returns true if LOCK is still locked, because other clients
+ also had it locked.
+
+ Returns false if LOCK has now been destroyed. In this case
+ the caller must ensure that any auxiliary data associated with
+ LOCK is destroyed, to avoid a memory leak. The caller must
+ obtain a pointer to the auxiliary data, e.g. via
+ fh_lock_get_aux *before* calling fh_unlock (because it yields
+ undefined behavior to call fh_lock_get_aux on a destroyed
+ lock). */
+bool
+fh_unlock (struct fh_lock *lock)
+{
+ if (lock != NULL)
+ {
+ assert (lock->open_cnt > 0);
+ if (--lock->open_cnt == 0)
+ {
+ hmap_delete (&locks, &lock->node);
+ free_key (lock);
+ free (lock);
+ return false;
+ }
+ }
+ return true;
+}
+
+/* Returns auxiliary data for LOCK.
+
+ Auxiliary data is shared by every client that holds LOCK (for
+ an exclusive lock, this is a single client). To avoid leaks,
+ auxiliary data must be released before LOCK is destroyed. */
+void *
+fh_lock_get_aux (const struct fh_lock *lock)
+{
+ return lock->aux;
+}
+
+/* Sets the auxiliary data for LOCK to AUX. */
+void
+fh_lock_set_aux (struct fh_lock *lock, void *aux)
+{
+ lock->aux = aux;
+}
+
+/* Returns true if HANDLE is locked for the given type of ACCESS,
+ false otherwise. */
+bool
+fh_is_locked (const struct file_handle *handle, enum fh_access access)
+{
+ struct fh_lock key;
+ const struct fh_lock *k = NULL;
+ bool is_locked = false;
+ size_t hash ;
+
+ make_key (&key, handle, access);
+
+ hash = hash_fh_lock (&key);
+
+
+ HMAP_FOR_EACH_WITH_HASH (k, struct fh_lock, node, hash, &locks)
+ {
+ if (0 == compare_fh_locks (k, &key))
+ {
+ is_locked = true;
+ break;
+ }
+ }
+
+ free_key (&key);
+
+ return is_locked;
+}
+
+/* Initializes the key fields in LOCK for looking up or inserting
+ handle H for the given kind of ACCESS. */
+static void
+make_key (struct fh_lock *lock, const struct file_handle *h,
+ enum fh_access access)
+{
+ lock->referent = fh_get_referent (h);
+ lock->access = access;
+ if (lock->referent == FH_REF_FILE)
+ lock->u.file = fh_get_identity (h);
+ else if (lock->referent == FH_REF_DATASET)
+ lock->u.unique_id = dataset_seqno (fh_get_dataset (h));
+}
+
+/* Frees the key fields in LOCK. */
+static void
+free_key (struct fh_lock *lock)
+{
+ if (lock->referent == FH_REF_FILE)
+ fh_free_identity (lock->u.file);
+}
+
+/* Compares the key fields in struct fh_lock objects A and B and
+ returns a strcmp()-type result. */
+static int
+compare_fh_locks (const struct fh_lock *a, const struct fh_lock *b)
+{
+ if (a->referent != b->referent)
+ return a->referent < b->referent ? -1 : 1;
+ else if (a->access != b->access)
+ return a->access < b->access ? -1 : 1;
+ else if (a->referent == FH_REF_FILE)
+ return fh_compare_file_identities (a->u.file, b->u.file);
+ else if (a->referent == FH_REF_DATASET)
+ return (a->u.unique_id < b->u.unique_id ? -1
+ : a->u.unique_id > b->u.unique_id);
+ else
+ return 0;
+}
+
+/* Returns a hash value for LOCK. */
+static unsigned int
+hash_fh_lock (const struct fh_lock *lock)
+{
+ unsigned int basis;
+ if (lock->referent == FH_REF_FILE)
+ basis = fh_hash_identity (lock->u.file);
+ else if (lock->referent == FH_REF_DATASET)
+ basis = lock->u.unique_id;
+ else
+ basis = 0;
+ return hash_int ((lock->referent << 3) | lock->access, basis);
+}
+
+\f
+
+
+
+
+/* A file's identity:
+
+ - For a file that exists, this is its device and inode.
+
+ - For a file that does not exist, but which has a directory
+ name that exists, this is the device and inode of the
+ directory, plus the file's base name.
+
+ - For a file that does not exist and has a nonexistent
+ directory, this is the file name.
+
+ Windows doesn't have inode numbers, so we just use the name
+ there. */
+struct file_identity
+{
+ unsigned long long device; /* Device number. */
+ unsigned long long inode; /* Inode number. */
+ char *name; /* File name, where needed, otherwise NULL. */
+};
+
+/* Returns a pointer to a dynamically allocated structure whose
+ value can be used to tell whether two files are actually the
+ same file. The caller is responsible for freeing the structure with
+ fh_free_identity() when finished. */
+static struct file_identity *
+fh_get_identity (const struct file_handle *fh)
+{
+ struct file_identity *identity = xmalloc (sizeof *identity);
+
+ const char *file_name = fh_get_file_name (fh);
+
+#if !(defined _WIN32 || defined __WIN32__)
+ struct stat s;
+ if (lstat (file_name, &s) == 0)
+ {
+ identity->device = s.st_dev;
+ identity->inode = s.st_ino;
+ identity->name = NULL;
+ }
+ else
+ {
+ char *dir = dir_name (file_name);
+ if (last_component (file_name) != NULL && stat (dir, &s) == 0)
+ {
+ identity->device = s.st_dev;
+ identity->inode = s.st_ino;
+ identity->name = base_name (file_name);
+ }
+ else
+ {
+ identity->device = 0;
+ identity->inode = 0;
+ identity->name = xstrdup (file_name);
+ }
+ free (dir);
+ }
+#else /* Windows */
+ bool ok = false;
+ HANDLE h = CreateFile (file_name, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_READONLY, NULL);
+ if (h != INVALID_HANDLE_VALUE)
+ {
+ BY_HANDLE_FILE_INFORMATION fi;
+ ok = GetFileInformationByHandle (h, &fi);
+ if (ok)
+ {
+ identity->device = fi.dwVolumeSerialNumber;
+ identity->inode = fi.nFileIndexHigh;
+ identity->inode <<= (sizeof fi.nFileIndexLow) * CHAR_BIT;
+ identity->inode |= fi.nFileIndexLow;
+ identity->name = 0;
+ }
+ CloseHandle (h);
+ }
+
+ if (!ok)
+ {
+ identity->device = 0;
+ identity->inode = 0;
+
+ size_t bufsize;
+ size_t pathlen = 255;
+ char *cname = NULL;
+ do
+ {
+ bufsize = pathlen;
+ cname = xrealloc (cname, bufsize);
+ pathlen = GetFullPathName (file_name, bufsize, cname, NULL);
+ }
+ while (pathlen > bufsize);
+ identity->name = xstrdup (cname);
+ free (cname);
+ str_lowercase (identity->name);
+ }
+#endif /* Windows */
+
+ return identity;
+}
+
+/* Frees IDENTITY obtained from fh_get_identity(). */
+void
+fh_free_identity (struct file_identity *identity)
+{
+ if (identity != NULL)
+ {
+ free (identity->name);
+ free (identity);
+ }
+}
+
+/* Compares A and B, returning a strcmp()-type result. */
+int
+fh_compare_file_identities (const struct file_identity *a,
+ const struct file_identity *b)
+{
+ if (a->device != b->device)
+ return a->device < b->device ? -1 : 1;
+ else if (a->inode != b->inode)
+ return a->inode < b->inode ? -1 : 1;
+ else if (a->name != NULL)
+ return b->name != NULL ? strcmp (a->name, b->name) : 1;
+ else
+ return b->name != NULL ? -1 : 0;
+}
+
+/* Returns a hash value for IDENTITY. */
+unsigned int
+fh_hash_identity (const struct file_identity *identity)
+{
+ unsigned int hash = hash_int (identity->device, identity->inode);
+ if (identity->name != NULL)
+ hash = hash_string (identity->name, hash);
+ return hash;
}
projects / pspp / blobdiff