1 /* Blue Sky: File Systems in the Cloud
3 * Copyright (C) 2009 The Regents of the University of California
4 * Written by Michael Vrable <mvrable@cs.ucsd.edu>
14 #include "bluesky-private.h"
16 /* Miscellaneous useful functions that don't really fit anywhere else. */
18 bluesky_time_hires bluesky_now_hires()
22 if (clock_gettime(CLOCK_REALTIME, &time) != 0) {
23 perror("clock_gettime");
27 return (int64_t)(time.tv_sec) * 1000000000 + time.tv_nsec;
30 /* Convert a UTF-8 string to lowercase. This can be used to implement
31 * case-insensitive lookups and comparisons, by normalizing all values to
32 * lowercase first. Returns a newly-allocated string as a result. */
33 gchar *bluesky_lowercase(const gchar *s)
35 /* TODO: Unicode handling; for now just do ASCII. */
36 return g_ascii_strdown(s, -1);
39 gboolean bluesky_inode_is_ready(BlueSkyInode *inode)
44 g_mutex_lock(inode->lock);
45 gboolean valid = (inode->type != BLUESKY_PENDING
46 && inode->type != BLUESKY_INVALID);
48 g_mutex_unlock(inode->lock);
53 /**** Reference-counted strings. ****/
55 /* Create and return a new reference-counted string. The reference count is
56 * initially one. The newly-returned string takes ownership of the memory
57 * pointed at by data, and will call g_free on it when the reference count
59 BlueSkyRCStr *bluesky_string_new(gpointer data, gsize len)
61 BlueSkyRCStr *string = g_new(BlueSkyRCStr, 1);
64 g_atomic_int_set(&string->refcount, 1);
68 /* Create a new BlueSkyRCStr from a GString. The GString is destroyed. */
69 BlueSkyRCStr *bluesky_string_new_from_gstring(GString *s)
72 return bluesky_string_new(g_string_free(s, FALSE), len);
75 void bluesky_string_ref(BlueSkyRCStr *string)
80 g_atomic_int_inc(&string->refcount);
83 void bluesky_string_unref(BlueSkyRCStr *string)
88 if (g_atomic_int_dec_and_test(&string->refcount)) {
94 /* Duplicate and return a new reference-counted string, containing a copy of
95 * the original data, with a reference count of 1. As an optimization, if the
96 * passed-in string already has a reference count of 1, the original is
97 * returned. Can be used to make a mutable copy of a shared string. For this
98 * to truly be safe, it is probably needed that there be some type of lock
99 * protecting access to the string. */
100 BlueSkyRCStr *bluesky_string_dup(BlueSkyRCStr *string)
105 if (g_atomic_int_dec_and_test(&string->refcount)) {
106 /* There are no other shared copies, so return this one. */
107 g_atomic_int_inc(&string->refcount);
110 return bluesky_string_new(g_memdup(string->data, string->len),
115 /* Resize the data block used by a BlueSkyRCStr. The data pointer might change
116 * after making this call, so it should not be cached across calls to this
117 * function. To avoid confusing any other users, the caller probably ought to
118 * hold the only reference to the string (by calling bluesky_string_dup first
120 void bluesky_string_resize(BlueSkyRCStr *string, gsize len)
122 if (string->len == len)
125 g_warn_if_fail(string->refcount == 1);
127 string->data = g_realloc(string->data, len);
131 /* Cache LRU list management functions. These manage the doubly-linked list of
132 * inodes sorted by accessed/modified time. The FS lock should be held while
135 * _remove will unlink an inode from the linked list.
137 * _prepend and _append insert an inode at the head or tail of the linked list,
138 * and return a pointer to the linked list element (which should be stored in
139 * the inode); the inode should not already be in the list.
141 * _head and _tail simply return the first or last item inode in the list. */
142 void bluesky_list_unlink(GList *head, GList *item)
147 if (head->prev == item)
148 head->prev = item->prev;
149 head->next = g_list_delete_link(head->next, item);
152 GList *bluesky_list_prepend(GList *head, BlueSkyInode *inode)
154 head->next = g_list_prepend(head->next, inode);
155 if (head->prev == NULL)
156 head->prev = g_list_last(head->next);
160 GList *bluesky_list_append(GList *head, BlueSkyInode *inode)
162 if (head->next == NULL)
163 return bluesky_list_prepend(head, inode);
165 g_assert(head->prev != NULL && head->prev->next == NULL);
167 GList *link = g_list_alloc();
170 link->prev = head->prev;
171 head->prev->next = link;
176 BlueSkyInode *bluesky_list_head(GList *head)
178 if (head->next == NULL)
181 return (BlueSkyInode *)head->next->data;
184 BlueSkyInode *bluesky_list_tail(GList *head)
186 if (head->prev == NULL)
189 return (BlueSkyInode *)head->prev->data;