/* Copyright libuv project contributors. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#ifndef UV_WIN_FS_FD_HASH_INL_H_
#define UV_WIN_FS_FD_HASH_INL_H_
#include "uv.h"
#include "internal.h"
/* Files are only inserted in uv__fd_hash when the UV_FS_O_FILEMAP flag is
* specified. Thus, when uv__fd_hash_get returns true, the file mapping in the
* info structure should be used for read/write operations.
*
* If the file is empty, the mapping field will be set to
* INVALID_HANDLE_VALUE. This is not an issue since the file mapping needs to
* be created anyway when the file size changes.
*
* Since file descriptors are sequential integers, the modulo operator is used
* as hashing function. For each bucket, a single linked list of arrays is
* kept to minimize allocations. A statically allocated memory buffer is kept
* for the first array in each bucket. */
#define UV__FD_HASH_SIZE 256
#define UV__FD_HASH_GROUP_SIZE 16
struct uv__fd_info_s {
int flags;
BOOLEAN is_directory;
HANDLE mapping;
LARGE_INTEGER size;
LARGE_INTEGER current_pos;
};
struct uv__fd_hash_entry_s {
uv_file fd;
struct uv__fd_info_s info;
};
struct uv__fd_hash_entry_group_s {
struct uv__fd_hash_entry_s entries[UV__FD_HASH_GROUP_SIZE];
struct uv__fd_hash_entry_group_s* next;
};
struct uv__fd_hash_bucket_s {
size_t size;
struct uv__fd_hash_entry_group_s* data;
};
static uv_mutex_t uv__fd_hash_mutex;
static struct uv__fd_hash_entry_group_s
uv__fd_hash_entry_initial[UV__FD_HASH_SIZE * UV__FD_HASH_GROUP_SIZE];
static struct uv__fd_hash_bucket_s uv__fd_hash[UV__FD_HASH_SIZE];
INLINE static void uv__fd_hash_init(void) {
size_t i;
int err;
err = uv_mutex_init(&uv__fd_hash_mutex);
if (err) {
uv_fatal_error(err, "uv_mutex_init");
}
for (i = 0; i < ARRAY_SIZE(uv__fd_hash); ++i) {
uv__fd_hash[i].size = 0;
uv__fd_hash[i].data =
uv__fd_hash_entry_initial + i * UV__FD_HASH_GROUP_SIZE;
}
}
#define FIND_COMMON_VARIABLES \
unsigned i; \
unsigned bucket = fd % ARRAY_SIZE(uv__fd_hash); \
struct uv__fd_hash_entry_s* entry_ptr = NULL; \
struct uv__fd_hash_entry_group_s* group_ptr; \
struct uv__fd_hash_bucket_s* bucket_ptr = &uv__fd_hash[bucket];
#define FIND_IN_GROUP_PTR(group_size) \
do { \
for (i = 0; i < group_size; ++i) { \
if (group_ptr->entries[i].fd == fd) { \
entry_ptr = &group_ptr->entries[i]; \
break; \
} \
} \
} while (0)
#define FIND_IN_BUCKET_PTR() \
do { \
size_t first_group_size = bucket_ptr->size % UV__FD_HASH_GROUP_SIZE; \
if (bucket_ptr->size != 0 && first_group_size == 0) \
first_group_size = UV__FD_HASH_GROUP_SIZE; \
group_ptr = bucket_ptr->data; \
FIND_IN_GROUP_PTR(first_group_size); \
for (group_ptr = group_ptr->next; \
group_ptr != NULL && entry_ptr == NULL; \
group_ptr = group_ptr->next) \
FIND_IN_GROUP_PTR(UV__FD_HASH_GROUP_SIZE); \
} while (0)
INLINE static int uv__fd_hash_get(int fd, struct uv__fd_info_s* info) {
FIND_COMMON_VARIABLES
uv_mutex_lock(&uv__fd_hash_mutex);
FIND_IN_BUCKET_PTR();
if (entry_ptr != NULL) {
*info = entry_ptr->info;
}
uv_mutex_unlock(&uv__fd_hash_mutex);
return entry_ptr != NULL;
}
INLINE static void uv__fd_hash_add(int fd, struct uv__fd_info_s* info) {
FIND_COMMON_VARIABLES
uv_mutex_lock(&uv__fd_hash_mutex);
FIND_IN_BUCKET_PTR();
if (entry_ptr == NULL) {
i = bucket_ptr->size % UV__FD_HASH_GROUP_SIZE;
if (bucket_ptr->size != 0 && i == 0) {
struct uv__fd_hash_entry_group_s* new_group_ptr =
uv__malloc(sizeof(*new_group_ptr));
if (new_group_ptr == NULL) {
uv_fatal_error(ERROR_OUTOFMEMORY, "uv__malloc");
}
new_group_ptr->next = bucket_ptr->data;
bucket_ptr->data = new_group_ptr;
}
bucket_ptr->size += 1;
entry_ptr = &bucket_ptr->data->entries[i];
entry_ptr->fd = fd;
}
entry_ptr->info = *info;
uv_mutex_unlock(&uv__fd_hash_mutex);
}
INLINE static int uv__fd_hash_remove(int fd, struct uv__fd_info_s* info) {
FIND_COMMON_VARIABLES
uv_mutex_lock(&uv__fd_hash_mutex);
FIND_IN_BUCKET_PTR();
if (entry_ptr != NULL) {
*info = entry_ptr->info;
bucket_ptr->size -= 1;
i = bucket_ptr->size % UV__FD_HASH_GROUP_SIZE;
if (entry_ptr != &bucket_ptr->data->entries[i]) {
*entry_ptr = bucket_ptr->data->entries[i];
}
if (bucket_ptr->size != 0 &&
bucket_ptr->size % UV__FD_HASH_GROUP_SIZE == 0) {
struct uv__fd_hash_entry_group_s* old_group_ptr = bucket_ptr->data;
bucket_ptr->data = old_group_ptr->next;
uv__free(old_group_ptr);
}
}
uv_mutex_unlock(&uv__fd_hash_mutex);
return entry_ptr != NULL;
}
#undef FIND_COMMON_VARIABLES
#undef FIND_IN_GROUP_PTR
#undef FIND_IN_BUCKET_PTR
#endif /* UV_WIN_FS_FD_HASH_INL_H_ */