From f4e8820bca53296af76224726b217bbedccee4d8 Mon Sep 17 00:00:00 2001 From: prife Date: Thu, 19 Dec 2013 13:08:37 +0800 Subject: [PATCH] dfs: refine more code clean code with pointer rather than index --- components/dfs/src/dfs_fs.c | 116 +++++++++++++++--------------------- 1 file changed, 49 insertions(+), 67 deletions(-) diff --git a/components/dfs/src/dfs_fs.c b/components/dfs/src/dfs_fs.c index 8ea9da469..7e1dbd358 100644 --- a/components/dfs/src/dfs_fs.c +++ b/components/dfs/src/dfs_fs.c @@ -37,48 +37,36 @@ * * @param ops the file system instance to be registered. * - * @return 0 on successful, -1 on failed. + * @return RT_EOK on successful, -RT_ERROR on failed. */ int dfs_register(const struct dfs_filesystem_operation *ops) { - int index, result; - int free_index; - - result = 0; - free_index = DFS_FILESYSTEM_TYPES_MAX; + int ret = RT_EOK; + const struct dfs_filesystem_operation **empty = RT_NULL; + const struct dfs_filesystem_operation **iter; /* lock filesystem */ dfs_lock(); - /* check if this filesystem was already registered */ - for (index = 0; index < DFS_FILESYSTEM_TYPES_MAX; index++) + for (iter = &filesystem_operation_table[0]; + iter < &filesystem_operation_table[DFS_FILESYSTEM_TYPES_MAX]; iter ++) { - if (filesystem_operation_table[index] == RT_NULL) + /* find out an empty filesystem type entry */ + if (*iter == RT_NULL) + (empty == RT_NULL) ? (empty = iter) : 0; + else if (strcmp((*iter)->name, ops->name) == 0) { - /* find out an empty filesystem type entry */ - if (free_index == DFS_FILESYSTEM_TYPES_MAX) - free_index = index; + ret = -1; + break; } - else if (strcmp(filesystem_operation_table[index]->name, ops->name) == 0) - { - result = -1; - goto err; - } - } - - /* filesystem type table full */ - if (free_index == DFS_FILESYSTEM_TYPES_MAX) - { - result = -1; - goto err; } /* save the filesystem's operations */ - filesystem_operation_table[free_index] = ops; + if ((ret == RT_EOK) && (empty != RT_NULL)) + *empty = ops; -err: dfs_unlock(); - return result; + return ret; } /** @@ -91,38 +79,38 @@ err: */ struct dfs_filesystem *dfs_filesystem_lookup(const char *path) { - struct dfs_filesystem *fs; - rt_uint32_t index, fspath, prefixlen; + struct dfs_filesystem *iter; + struct dfs_filesystem *empty = RT_NULL; + rt_uint32_t fspath, prefixlen; - fs = RT_NULL; prefixlen = 0; /* lock filesystem */ dfs_lock(); /* lookup it in the filesystem table */ - for (index = 0; index < DFS_FILESYSTEMS_MAX; index++) + for (iter = &filesystem_table[0]; + iter < &filesystem_table[DFS_FILESYSTEMS_MAX]; iter++) { - if ((filesystem_table[index].path == RT_NULL) - || (filesystem_table[index].ops == RT_NULL)) + if ((iter->path == RT_NULL) || (iter->ops == RT_NULL)) continue; - fspath = strlen(filesystem_table[index].path); + fspath = strlen(iter->path); if ((fspath < prefixlen) - || (strncmp(filesystem_table[index].path, path, fspath) != 0)) + || (strncmp(iter->path, path, fspath) != 0)) continue; /* check next path separator */ if (fspath > 1 && (strlen(path) > fspath) && (path[fspath] != '/')) continue; - fs = &filesystem_table[index]; + empty = iter; prefixlen = fspath; } dfs_unlock(); - return fs; + return empty; } /** @@ -198,11 +186,11 @@ int dfs_mount(const char *device_name, unsigned long rwflag, const void *data) { - const struct dfs_filesystem_operation *ops; - struct dfs_filesystem *fs; - char *fullpath=RT_NULL; + const struct dfs_filesystem_operation **ops; + struct dfs_filesystem *iter; + struct dfs_filesystem *fs = RT_NULL; + char *fullpath = RT_NULL; rt_device_t dev_id; - int index, free_index; /* open specific device */ if (device_name == RT_NULL) @@ -217,28 +205,25 @@ int dfs_mount(const char *device_name, return -1; } - /* find out specific filesystem */ + /* find out the specific filesystem */ dfs_lock(); - for (index = 0; index < DFS_FILESYSTEM_TYPES_MAX; index++) - { - if (filesystem_operation_table[index] == RT_NULL) - continue; - if (strcmp(filesystem_operation_table[index]->name, filesystemtype) == 0) + for (ops = &filesystem_operation_table[0]; + ops < &filesystem_operation_table[DFS_FILESYSTEM_TYPES_MAX]; ops++) + if ((ops != RT_NULL) && (strcmp((*ops)->name, filesystemtype) == 0)) break; - } + dfs_unlock(); - /* can't find filesystem */ - if (index == DFS_FILESYSTEM_TYPES_MAX) + if (ops == &filesystem_operation_table[DFS_FILESYSTEM_TYPES_MAX]) { + /* can't find filesystem */ rt_set_errno(-DFS_STATUS_ENODEV); return -1; } /* check if there is mount implementation */ - ops = filesystem_operation_table[index]; - if ((ops == NULL) || (ops->mount == NULL)) + if ((*ops == NULL) || ((*ops)->mount == NULL)) { rt_set_errno(-DFS_STATUS_ENOSYS); return -1; @@ -267,36 +252,33 @@ int dfs_mount(const char *device_name, dfs_file_close(&fd); } - /* check whether the file system mounted or not */ - free_index = DFS_FILESYSTEMS_MAX; + /* check whether the file system mounted or not in the filesystem table + * if it is unmounted yet, find out an empty entry */ dfs_lock(); - for (index = 0; index < DFS_FILESYSTEMS_MAX; index ++) + + for (iter = &filesystem_table[0]; + iter < &filesystem_table[DFS_FILESYSTEMS_MAX]; iter++) { - if (filesystem_table[index].ops == RT_NULL) - { - /* find out an empty filesystem table entry */ - if (free_index == DFS_FILESYSTEMS_MAX) - free_index = index; - } + /* check if it is an empty filesystem table entry? if it is, save fs */ + if (iter->ops == RT_NULL) + (fs == RT_NULL) ? (fs = iter) : 0; /* check if the PATH is mounted */ - else if (strcmp(filesystem_table[index].path, path) == 0) + else if (strcmp(iter->path, path) == 0) { rt_set_errno(-DFS_STATUS_EINVAL); goto err1; } } - /* can't find en empty filesystem table entry */ - if (free_index == DFS_FILESYSTEMS_MAX) + if ((fs == RT_NULL) && (iter == &filesystem_table[DFS_FILESYSTEMS_MAX])) { rt_set_errno(-DFS_STATUS_ENOSPC); goto err1; } /* register file system */ - fs = &(filesystem_table[free_index]); fs->path = fullpath; - fs->ops = ops; + fs->ops = *ops; fs->dev_id = dev_id; /* release filesystem_table lock */ dfs_unlock(); @@ -306,7 +288,7 @@ int dfs_mount(const char *device_name, rt_device_open(fs->dev_id, RT_DEVICE_OFLAG_RDWR); /* call mount of this filesystem */ - if (ops->mount(fs, rwflag, data) < 0) + if ((*ops)->mount(fs, rwflag, data) < 0) { /* close device */ if (dev_id != RT_NULL)