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>
13 #include "bluesky-private.h"
15 /* Interaction with cloud storage. We expose very simple GET/PUT style
16 * interface, which different backends can implement. Available backends
17 * (will) include Amazon S3 and a simple local store for testing purposes.
18 * Operations may be performed asynchronously. */
20 struct _BlueSkyStore {
21 const BlueSkyStoreImplementation *impl;
26 int pending; /* Count of operations not yet complete. */
29 GHashTable *store_implementations;
31 /* Thread pool for calling notifier functions when an operation completes.
32 * These are called in a separate thread for locking reasons: we want to call
33 * the notifiers without the lock on the async object held, but completion
34 * occurs when the lock is held--so we need some way to defer the call. This
35 * isn't really optimal from a cache-locality standpoint. */
36 static GThreadPool *notifier_thread_pool;
38 void bluesky_store_register(const BlueSkyStoreImplementation *impl,
41 g_hash_table_insert(store_implementations, g_strdup(name), (gpointer)impl);
44 BlueSkyStore *bluesky_store_new(const gchar *type)
46 const BlueSkyStoreImplementation *impl;
48 impl = g_hash_table_lookup(store_implementations, type);
52 gpointer handle = impl->create();
56 BlueSkyStore *store = g_new(BlueSkyStore, 1);
58 store->handle = handle;
59 store->lock = g_mutex_new();
60 store->cond_idle = g_cond_new();
65 void bluesky_store_free(BlueSkyStore *store)
67 store->impl->destroy(store->handle);
71 BlueSkyStoreAsync *bluesky_store_async_new(BlueSkyStore *store)
73 BlueSkyStoreAsync *async;
75 async = g_new(BlueSkyStoreAsync, 1);
77 async->lock = g_mutex_new();
78 async->completion_cond = g_cond_new();
80 async->status = ASYNC_NEW;
81 async->op = STORE_OP_NONE;
85 async->notifiers = NULL;
86 async->store_private = NULL;
91 gpointer bluesky_store_async_get_handle(BlueSkyStoreAsync *async)
93 return async->store->handle;
96 void bluesky_store_async_ref(BlueSkyStoreAsync *async)
101 g_return_if_fail(g_atomic_int_get(&async->refcount) > 0);
103 g_atomic_int_inc(&async->refcount);
106 void bluesky_store_async_unref(BlueSkyStoreAsync *async)
111 if (g_atomic_int_dec_and_test(&async->refcount)) {
112 async->store->impl->cleanup(async->store->handle, async);
113 g_mutex_free(async->lock);
114 g_cond_free(async->completion_cond);
116 bluesky_string_unref(async->data);
121 /* Block until the given operation has completed. */
122 void bluesky_store_async_wait(BlueSkyStoreAsync *async)
124 g_return_if_fail(async != NULL);
125 g_mutex_lock(async->lock);
127 if (async->status == ASYNC_NEW) {
128 g_error("bluesky_store_async_wait on a new async object!\n");
129 g_mutex_unlock(async->lock);
133 while (async->status != ASYNC_COMPLETE) {
134 g_cond_wait(async->completion_cond, async->lock);
137 g_mutex_unlock(async->lock);
140 /* Add a notifier function to be called when the operation completes. */
141 void bluesky_store_async_add_notifier(BlueSkyStoreAsync *async,
142 GFunc func, gpointer user_data)
144 struct BlueSkyNotifierList *nl = g_new(struct BlueSkyNotifierList, 1);
145 nl->next = async->notifiers;
147 nl->async = async; bluesky_store_async_ref(async);
148 nl->user_data = user_data;
149 if (async->status == ASYNC_COMPLETE) {
150 g_thread_pool_push(notifier_thread_pool, nl, NULL);
152 async->notifiers = nl;
156 /* Mark an asynchronous operation as complete. This should only be called by
157 * the store implementations. The lock should be held when calling this
158 * function. Any notifier functions will be called, but in a separate thread
159 * and without the lock held. */
160 void bluesky_store_async_mark_complete(BlueSkyStoreAsync *async)
162 g_return_if_fail(async->status != ASYNC_COMPLETE);
164 bluesky_time_hires elapsed = bluesky_now_hires() - async->start_time;
166 g_mutex_lock(async->store->lock);
167 async->store->pending--;
168 if (async->store->pending == 0)
169 g_cond_broadcast(async->store->cond_idle);
170 g_mutex_unlock(async->store->lock);
172 async->status = ASYNC_COMPLETE;
173 g_cond_broadcast(async->completion_cond);
175 while (async->notifiers != NULL) {
176 struct BlueSkyNotifierList *nl = async->notifiers;
177 async->notifiers = nl->next;
178 g_thread_pool_push(notifier_thread_pool, nl, NULL);
181 g_log("bluesky/store", G_LOG_LEVEL_DEBUG,
182 "[%p] complete: elapsed = %"PRIi64" ns",
186 void bluesky_store_async_submit(BlueSkyStoreAsync *async)
188 BlueSkyStore *store = async->store;
190 async->start_time = bluesky_now_hires();
192 g_log("bluesky/store", G_LOG_LEVEL_DEBUG, "[%p] submit: %s %s",
194 async->op == STORE_OP_GET ? "GET"
195 : async->op == STORE_OP_PUT ? "PUT"
196 : async->op == STORE_OP_DELETE ? "DELETE"
197 : async->op == STORE_OP_BARRIER ? "BARRIER" : "???",
200 /* Barriers are handled specially, and not handed down the storage
201 * implementation layer. */
202 if (async->op == STORE_OP_BARRIER) {
203 async->status = ASYNC_RUNNING;
204 if (GPOINTER_TO_INT(async->store_private) == 0)
205 bluesky_store_async_mark_complete(async);
209 g_mutex_lock(async->store->lock);
210 async->store->pending++;
211 g_mutex_unlock(async->store->lock);
213 store->impl->submit(store->handle, async);
215 if (bluesky_options.synchronous_stores)
216 bluesky_store_async_wait(async);
219 static void op_complete(gpointer a, gpointer b)
221 BlueSkyStoreAsync *barrier = (BlueSkyStoreAsync *)b;
223 bluesky_store_async_ref(barrier);
224 g_mutex_lock(barrier->lock);
225 barrier->store_private
226 = GINT_TO_POINTER(GPOINTER_TO_INT(barrier->store_private) - 1);
227 if (GPOINTER_TO_INT(barrier->store_private) == 0
228 && barrier->status != ASYNC_NEW) {
229 bluesky_store_async_mark_complete(barrier);
231 g_mutex_unlock(barrier->lock);
232 bluesky_store_async_unref(barrier);
235 /* Add the given operation to the barrier. The barrier will not complete until
236 * all operations added to it have completed. */
237 void bluesky_store_add_barrier(BlueSkyStoreAsync *barrier,
238 BlueSkyStoreAsync *async)
240 g_return_if_fail(barrier->op == STORE_OP_BARRIER);
241 barrier->store_private
242 = GINT_TO_POINTER(GPOINTER_TO_INT(barrier->store_private) + 1);
243 bluesky_store_async_add_notifier(async, op_complete, barrier);
246 static void notifier_task(gpointer n, gpointer s)
248 struct BlueSkyNotifierList *notifier = (struct BlueSkyNotifierList *)n;
250 notifier->func(notifier->async, notifier->user_data);
251 bluesky_store_async_unref(notifier->async);
255 void bluesky_store_sync(BlueSkyStore *store)
257 g_mutex_lock(store->lock);
258 g_print("Waiting for pending store operations to complete...\n");
259 while (store->pending > 0) {
260 g_cond_wait(store->cond_idle, store->lock);
262 g_mutex_unlock(store->lock);
263 g_print("Operations are complete.\n");
266 /* Convenience wrappers that perform a single operation synchronously. */
267 BlueSkyRCStr *bluesky_store_get(BlueSkyStore *store, const gchar *key)
269 BlueSkyStoreAsync *async = bluesky_store_async_new(store);
270 async->op = STORE_OP_GET;
271 async->key = g_strdup(key);
272 bluesky_store_async_submit(async);
274 bluesky_store_async_wait(async);
276 BlueSkyRCStr *data = async->data;
277 bluesky_string_ref(data);
278 bluesky_store_async_unref(async);
282 void bluesky_store_put(BlueSkyStore *store,
283 const gchar *key, BlueSkyRCStr *val)
285 BlueSkyStoreAsync *async = bluesky_store_async_new(store);
286 async->op = STORE_OP_PUT;
287 async->key = g_strdup(key);
288 bluesky_string_ref(val);
290 bluesky_store_async_submit(async);
292 bluesky_store_async_wait(async);
293 bluesky_store_async_unref(async);
296 /* Simple in-memory data store for test purposes. */
300 /* TODO: A hashtable isn't optimal for list queries... */
304 static gpointer memstore_create()
306 MemStore *store = g_new(MemStore, 1);
307 store->lock = g_mutex_new();
308 store->store = g_hash_table_new_full(g_str_hash, g_str_equal,
310 (GDestroyNotify)bluesky_string_unref);
312 return (gpointer)store;
315 static void memstore_destroy(gpointer store)
320 static BlueSkyRCStr *memstore_get(gpointer st, const gchar *key)
322 MemStore *store = (MemStore *)st;
323 BlueSkyRCStr *s = g_hash_table_lookup(store->store, key);
325 bluesky_string_ref(s);
329 static void memstore_put(gpointer s, const gchar *key, BlueSkyRCStr *val)
331 MemStore *store = (MemStore *)s;
332 bluesky_string_ref(val);
333 g_hash_table_insert(store->store, g_strdup(key), val);
336 static void memstore_submit(gpointer s, BlueSkyStoreAsync *async)
338 g_return_if_fail(async->status == ASYNC_NEW);
339 g_return_if_fail(async->op != STORE_OP_NONE);
343 async->data = memstore_get(s, async->key);
347 memstore_put(s, async->key, async->data);
351 g_warning("Uknown operation type for MemStore: %d\n", async->op);
355 bluesky_store_async_mark_complete(async);
358 static void memstore_cleanup(gpointer store, BlueSkyStoreAsync *async)
362 static BlueSkyStoreImplementation memstore_impl = {
363 .create = memstore_create,
364 .destroy = memstore_destroy,
365 .submit = memstore_submit,
366 .cleanup = memstore_cleanup,
369 /* Store implementation which writes data as files to disk. */
370 static gpointer filestore_create()
372 return GINT_TO_POINTER(1);
375 static void filestore_destroy()
379 static BlueSkyRCStr *filestore_get(const gchar *key)
381 gchar *contents = NULL;
383 GError *error = NULL;
385 g_file_get_contents(key, &contents, &length, &error);
386 if (contents == NULL)
389 return bluesky_string_new(contents, length);
392 static void filestore_put(const gchar *key, BlueSkyRCStr *val)
394 g_file_set_contents(key, val->data, val->len, NULL);
397 static void filestore_submit(gpointer s, BlueSkyStoreAsync *async)
399 g_return_if_fail(async->status == ASYNC_NEW);
400 g_return_if_fail(async->op != STORE_OP_NONE);
404 async->data = filestore_get(async->key);
409 filestore_put(async->key, async->data);
414 g_warning("Uknown operation type for FileStore: %d\n", async->op);
418 bluesky_store_async_mark_complete(async);
421 static void filestore_cleanup(gpointer store, BlueSkyStoreAsync *async)
425 static BlueSkyStoreImplementation filestore_impl = {
426 .create = filestore_create,
427 .destroy = filestore_destroy,
428 .submit = filestore_submit,
429 .cleanup = filestore_cleanup,
432 void bluesky_store_init()
434 store_implementations = g_hash_table_new(g_str_hash, g_str_equal);
435 notifier_thread_pool = g_thread_pool_new(notifier_task, NULL, -1, FALSE,
437 bluesky_store_register(&memstore_impl, "mem");
438 bluesky_store_register(&filestore_impl, "file");