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authorTor Andersson <tor.andersson@artifex.com>2013-06-19 15:29:44 +0200
committerTor Andersson <tor.andersson@artifex.com>2013-06-20 16:45:35 +0200
commit0a927854a10e1e6b9770a81e2e1d9f3093631757 (patch)
tree3d65d820d9fdba2d0d394d99c36290c851b78ca0 /fitz/res_store.c
parent1ae8f19179c5f0f8c6352b3c7855465325d5449a (diff)
downloadmupdf-0a927854a10e1e6b9770a81e2e1d9f3093631757.tar.xz
Rearrange source files.
Diffstat (limited to 'fitz/res_store.c')
-rw-r--r--fitz/res_store.c638
1 files changed, 0 insertions, 638 deletions
diff --git a/fitz/res_store.c b/fitz/res_store.c
deleted file mode 100644
index 609f10dc..00000000
--- a/fitz/res_store.c
+++ /dev/null
@@ -1,638 +0,0 @@
-#include "mupdf/fitz.h"
-
-typedef struct fz_item_s fz_item;
-
-struct fz_item_s
-{
- void *key;
- fz_storable *val;
- unsigned int size;
- fz_item *next;
- fz_item *prev;
- fz_store *store;
- fz_store_type *type;
-};
-
-struct fz_store_s
-{
- int refs;
-
- /* Every item in the store is kept in a doubly linked list, ordered
- * by usage (so LRU entries are at the end). */
- fz_item *head;
- fz_item *tail;
-
- /* We have a hash table that allows to quickly find a subset of the
- * entries (those whose keys are indirect objects). */
- fz_hash_table *hash;
-
- /* We keep track of the size of the store, and keep it below max. */
- unsigned int max;
- unsigned int size;
-};
-
-void
-fz_new_store_context(fz_context *ctx, unsigned int max)
-{
- fz_store *store;
- store = fz_malloc_struct(ctx, fz_store);
- fz_try(ctx)
- {
- store->hash = fz_new_hash_table(ctx, 4096, sizeof(fz_store_hash), FZ_LOCK_ALLOC);
- }
- fz_catch(ctx)
- {
- fz_free(ctx, store);
- fz_rethrow(ctx);
- }
- store->refs = 1;
- store->head = NULL;
- store->tail = NULL;
- store->size = 0;
- store->max = max;
- ctx->store = store;
-}
-
-void *
-fz_keep_storable(fz_context *ctx, fz_storable *s)
-{
- if (s == NULL)
- return NULL;
- fz_lock(ctx, FZ_LOCK_ALLOC);
- if (s->refs > 0)
- s->refs++;
- fz_unlock(ctx, FZ_LOCK_ALLOC);
- return s;
-}
-
-void
-fz_drop_storable(fz_context *ctx, fz_storable *s)
-{
- int do_free = 0;
-
- if (s == NULL)
- return;
- fz_lock(ctx, FZ_LOCK_ALLOC);
- if (s->refs < 0)
- {
- /* It's a static object. Dropping does nothing. */
- }
- else if (--s->refs == 0)
- {
- /* If we are dropping the last reference to an object, then
- * it cannot possibly be in the store (as the store always
- * keeps a ref to everything in it, and doesn't drop via
- * this method. So we can simply drop the storable object
- * itself without any operations on the fz_store. */
- do_free = 1;
- }
- fz_unlock(ctx, FZ_LOCK_ALLOC);
- if (do_free)
- s->free(ctx, s);
-}
-
-static void
-evict(fz_context *ctx, fz_item *item)
-{
- fz_store *store = ctx->store;
- int drop;
-
- store->size -= item->size;
- /* Unlink from the linked list */
- if (item->next)
- item->next->prev = item->prev;
- else
- store->tail = item->prev;
- if (item->prev)
- item->prev->next = item->next;
- else
- store->head = item->next;
- /* Drop a reference to the value (freeing if required) */
- drop = (item->val->refs > 0 && --item->val->refs == 0);
- /* Remove from the hash table */
- if (item->type->make_hash_key)
- {
- fz_store_hash hash = { NULL };
- hash.free = item->val->free;
- if (item->type->make_hash_key(&hash, item->key))
- fz_hash_remove(ctx, store->hash, &hash);
- }
- fz_unlock(ctx, FZ_LOCK_ALLOC);
- if (drop)
- item->val->free(ctx, item->val);
- /* Always drops the key and free the item */
- item->type->drop_key(ctx, item->key);
- fz_free(ctx, item);
- fz_lock(ctx, FZ_LOCK_ALLOC);
-}
-
-static int
-ensure_space(fz_context *ctx, unsigned int tofree)
-{
- fz_item *item, *prev;
- unsigned int count;
- fz_store *store = ctx->store;
-
- fz_assert_lock_held(ctx, FZ_LOCK_ALLOC);
-
- /* First check that we *can* free tofree; if not, we'd rather not
- * cache this. */
- count = 0;
- for (item = store->tail; item; item = item->prev)
- {
- if (item->val->refs == 1)
- {
- count += item->size;
- if (count >= tofree)
- break;
- }
- }
-
- /* If we ran out of items to search, then we can never free enough */
- if (item == NULL)
- {
- return 0;
- }
-
- /* Actually free the items */
- count = 0;
- for (item = store->tail; item; item = prev)
- {
- prev = item->prev;
- if (item->val->refs == 1)
- {
- /* Free this item. Evict has to drop the lock to
- * manage that, which could cause prev to be removed
- * in the meantime. To avoid that we bump its reference
- * count here. This may cause another simultaneous
- * evict process to fail to make enough space as prev is
- * pinned - but that will only happen if we're near to
- * the limit anyway, and it will only cause something to
- * not be cached. */
- count += item->size;
- if (prev)
- prev->val->refs++;
- evict(ctx, item); /* Drops then retakes lock */
- /* So the store has 1 reference to prev, as do we, so
- * no other evict process can have thrown prev away in
- * the meantime. So we are safe to just decrement its
- * reference count here. */
- if (prev)
- --prev->val->refs;
-
- if (count >= tofree)
- return count;
- }
- }
-
- return count;
-}
-
-static void
-touch(fz_store *store, fz_item *item)
-{
- if (item->next != item)
- {
- /* Already in the list - unlink it */
- if (item->next)
- item->next->prev = item->prev;
- else
- store->tail = item->prev;
- if (item->prev)
- item->prev->next = item->next;
- else
- store->head = item->next;
- }
- /* Now relink it at the start of the LRU chain */
- item->next = store->head;
- if (item->next)
- item->next->prev = item;
- else
- store->tail = item;
- store->head = item;
- item->prev = NULL;
-}
-
-void *
-fz_store_item(fz_context *ctx, void *key, void *val_, unsigned int itemsize, fz_store_type *type)
-{
- fz_item *item = NULL;
- unsigned int size;
- fz_storable *val = (fz_storable *)val_;
- fz_store *store = ctx->store;
- fz_store_hash hash = { NULL };
- int use_hash = 0;
- unsigned pos;
-
- if (!store)
- return NULL;
-
- fz_var(item);
-
- if (store->max != FZ_STORE_UNLIMITED && store->max < itemsize)
- {
- /* Our item would take up more room than we can ever
- * possibly have in the store. Just give up now. */
- return NULL;
- }
-
- /* If we fail for any reason, we swallow the exception and continue.
- * All that the above program will see is that we failed to store
- * the item. */
- fz_try(ctx)
- {
- item = fz_malloc_struct(ctx, fz_item);
- }
- fz_catch(ctx)
- {
- return NULL;
- }
-
- if (type->make_hash_key)
- {
- hash.free = val->free;
- use_hash = type->make_hash_key(&hash, key);
- }
-
- type->keep_key(ctx, key);
- fz_lock(ctx, FZ_LOCK_ALLOC);
-
- /* Fill out the item. To start with, we always set item->next == item
- * and item->prev == item. This is so that we can spot items that have
- * been put into the hash table without having made it into the linked
- * list yet. */
- item->key = key;
- item->val = val;
- item->size = itemsize;
- item->next = item;
- item->prev = item;
- item->type = type;
-
- /* If we can index it fast, put it into the hash table. This serves
- * to check whether we have one there already. */
- if (use_hash)
- {
- fz_item *existing;
-
- fz_try(ctx)
- {
- /* May drop and retake the lock */
- existing = fz_hash_insert_with_pos(ctx, store->hash, &hash, item, &pos);
- }
- fz_catch(ctx)
- {
- /* Any error here means that item never made it into the
- * hash - so no one else can have a reference. */
- fz_unlock(ctx, FZ_LOCK_ALLOC);
- fz_free(ctx, item);
- type->drop_key(ctx, key);
- return NULL;
- }
- if (existing)
- {
- /* There was one there already! Take a new reference
- * to the existing one, and drop our current one. */
- touch(store, existing);
- if (existing->val->refs > 0)
- existing->val->refs++;
- fz_unlock(ctx, FZ_LOCK_ALLOC);
- fz_free(ctx, item);
- type->drop_key(ctx, key);
- return existing->val;
- }
- }
- /* Now bump the ref */
- if (val->refs > 0)
- val->refs++;
- /* If we haven't got an infinite store, check for space within it */
- if (store->max != FZ_STORE_UNLIMITED)
- {
- size = store->size + itemsize;
- while (size > store->max)
- {
- /* ensure_space may drop, then retake the lock */
- int saved = ensure_space(ctx, size - store->max);
- if (saved == 0)
- {
- /* Failed to free any space. */
- /* If we are using the hash table, then we've already
- * inserted item - remove it. */
- if (use_hash)
- {
- /* If someone else has already picked up a reference
- * to item, then we cannot remove it. Leave it in the
- * store, and we'll live with being over budget. We
- * know this is the case, if it's in the linked list. */
- if (item->next != item)
- break;
- fz_hash_remove_fast(ctx, store->hash, &hash, pos);
- }
- fz_unlock(ctx, FZ_LOCK_ALLOC);
- fz_free(ctx, item);
- type->drop_key(ctx, key);
- if (val->refs > 0)
- val->refs--;
- return NULL;
- }
- size -= saved;
- }
- }
- store->size += itemsize;
-
- /* Regardless of whether it's indexed, it goes into the linked list */
- touch(store, item);
- fz_unlock(ctx, FZ_LOCK_ALLOC);
-
- return NULL;
-}
-
-void *
-fz_find_item(fz_context *ctx, fz_store_free_fn *free, void *key, fz_store_type *type)
-{
- fz_item *item;
- fz_store *store = ctx->store;
- fz_store_hash hash = { NULL };
- int use_hash = 0;
-
- if (!store)
- return NULL;
-
- if (!key)
- return NULL;
-
- if (type->make_hash_key)
- {
- hash.free = free;
- use_hash = type->make_hash_key(&hash, key);
- }
-
- fz_lock(ctx, FZ_LOCK_ALLOC);
- if (use_hash)
- {
- /* We can find objects keyed on indirected objects quickly */
- item = fz_hash_find(ctx, store->hash, &hash);
- }
- else
- {
- /* Others we have to hunt for slowly */
- for (item = store->head; item; item = item->next)
- {
- if (item->val->free == free && !type->cmp_key(item->key, key))
- break;
- }
- }
- if (item)
- {
- /* LRU the block. This also serves to ensure that any item
- * picked up from the hash before it has made it into the
- * linked list does not get whipped out again due to the
- * store being full. */
- touch(store, item);
- /* And bump the refcount before returning */
- if (item->val->refs > 0)
- item->val->refs++;
- fz_unlock(ctx, FZ_LOCK_ALLOC);
- return (void *)item->val;
- }
- fz_unlock(ctx, FZ_LOCK_ALLOC);
-
- return NULL;
-}
-
-void
-fz_remove_item(fz_context *ctx, fz_store_free_fn *free, void *key, fz_store_type *type)
-{
- fz_item *item;
- fz_store *store = ctx->store;
- int drop;
- fz_store_hash hash = { NULL };
- int use_hash = 0;
-
- if (type->make_hash_key)
- {
- hash.free = free;
- use_hash = type->make_hash_key(&hash, key);
- }
-
- fz_lock(ctx, FZ_LOCK_ALLOC);
- if (use_hash)
- {
- /* We can find objects keyed on indirect objects quickly */
- item = fz_hash_find(ctx, store->hash, &hash);
- if (item)
- fz_hash_remove(ctx, store->hash, &hash);
- }
- else
- {
- /* Others we have to hunt for slowly */
- for (item = store->head; item; item = item->next)
- if (item->val->free == free && !type->cmp_key(item->key, key))
- break;
- }
- if (item)
- {
- /* Momentarily things can be in the hash table without being
- * in the list. Don't attempt to unlink these. We indicate
- * such items by setting item->next == item. */
- if (item->next != item)
- {
- if (item->next)
- item->next->prev = item->prev;
- else
- store->tail = item->prev;
- if (item->prev)
- item->prev->next = item->next;
- else
- store->head = item->next;
- }
- drop = (item->val->refs > 0 && --item->val->refs == 0);
- fz_unlock(ctx, FZ_LOCK_ALLOC);
- if (drop)
- item->val->free(ctx, item->val);
- type->drop_key(ctx, item->key);
- fz_free(ctx, item);
- }
- else
- fz_unlock(ctx, FZ_LOCK_ALLOC);
-}
-
-void
-fz_empty_store(fz_context *ctx)
-{
- fz_store *store = ctx->store;
-
- if (store == NULL)
- return;
-
- fz_lock(ctx, FZ_LOCK_ALLOC);
- /* Run through all the items in the store */
- while (store->head)
- {
- evict(ctx, store->head); /* Drops then retakes lock */
- }
- fz_unlock(ctx, FZ_LOCK_ALLOC);
-}
-
-fz_store *
-fz_keep_store_context(fz_context *ctx)
-{
- if (ctx == NULL || ctx->store == NULL)
- return NULL;
- fz_lock(ctx, FZ_LOCK_ALLOC);
- ctx->store->refs++;
- fz_unlock(ctx, FZ_LOCK_ALLOC);
- return ctx->store;
-}
-
-void
-fz_drop_store_context(fz_context *ctx)
-{
- int refs;
- if (ctx == NULL || ctx->store == NULL)
- return;
- fz_lock(ctx, FZ_LOCK_ALLOC);
- refs = --ctx->store->refs;
- fz_unlock(ctx, FZ_LOCK_ALLOC);
- if (refs != 0)
- return;
-
- fz_empty_store(ctx);
- fz_free_hash(ctx, ctx->store->hash);
- fz_free(ctx, ctx->store);
- ctx->store = NULL;
-}
-
-#ifndef NDEBUG
-static void
-print_item(FILE *out, void *item_)
-{
- fz_item *item = (fz_item *)item_;
- fprintf(out, " val=%p item=%p\n", item->val, item);
- fflush(out);
-}
-
-void
-fz_print_store_locked(fz_context *ctx, FILE *out)
-{
- fz_item *item, *next;
- fz_store *store = ctx->store;
-
- fprintf(out, "-- resource store contents --\n");
- fflush(out);
-
- for (item = store->head; item; item = next)
- {
- next = item->next;
- if (next)
- next->val->refs++;
- fprintf(out, "store[*][refs=%d][size=%d] ", item->val->refs, item->size);
- fz_unlock(ctx, FZ_LOCK_ALLOC);
- item->type->debug(out, item->key);
- fprintf(out, " = %p\n", item->val);
- fflush(out);
- fz_lock(ctx, FZ_LOCK_ALLOC);
- if (next)
- next->val->refs--;
- }
- fprintf(out, "-- resource store hash contents --\n");
- fz_print_hash_details(ctx, out, store->hash, print_item);
- fprintf(out, "-- end --\n");
- fflush(out);
-}
-
-void
-fz_print_store(fz_context *ctx, FILE *out)
-{
- fz_lock(ctx, FZ_LOCK_ALLOC);
- fz_print_store_locked(ctx, out);
- fz_unlock(ctx, FZ_LOCK_ALLOC);
-}
-#endif
-
-/* This is now an n^2 algorithm - not ideal, but it'll only be bad if we are
- * actually managing to scavenge lots of blocks back. */
-static int
-scavenge(fz_context *ctx, unsigned int tofree)
-{
- fz_store *store = ctx->store;
- unsigned int count = 0;
- fz_item *item, *prev;
-
- /* Free the items */
- for (item = store->tail; item; item = prev)
- {
- prev = item->prev;
- if (item->val->refs == 1)
- {
- /* Free this item */
- count += item->size;
- evict(ctx, item); /* Drops then retakes lock */
-
- if (count >= tofree)
- break;
-
- /* Have to restart search again, as prev may no longer
- * be valid due to release of lock in evict. */
- prev = store->tail;
- }
- }
- /* Success is managing to evict any blocks */
- return count != 0;
-}
-
-int fz_store_scavenge(fz_context *ctx, unsigned int size, int *phase)
-{
- fz_store *store;
- unsigned int max;
-
- if (ctx == NULL)
- return 0;
- store = ctx->store;
- if (store == NULL)
- return 0;
-
-#ifdef DEBUG_SCAVENGING
- printf("Scavenging: store=%d size=%d phase=%d\n", store->size, size, *phase);
- fz_print_store_locked(ctx, stderr);
- Memento_stats();
-#endif
- do
- {
- unsigned int tofree;
-
- /* Calculate 'max' as the maximum size of the store for this phase */
- if (*phase >= 16)
- max = 0;
- else if (store->max != FZ_STORE_UNLIMITED)
- max = store->max / 16 * (16 - *phase);
- else
- max = store->size / (16 - *phase) * (15 - *phase);
- (*phase)++;
-
- /* Slightly baroque calculations to avoid overflow */
- if (size > UINT_MAX - store->size)
- tofree = UINT_MAX - max;
- else if (size + store->size > max)
- continue;
- else
- tofree = size + store->size - max;
-
- if (scavenge(ctx, tofree))
- {
-#ifdef DEBUG_SCAVENGING
- printf("scavenged: store=%d\n", store->size);
- fz_print_store(ctx, stderr);
- Memento_stats();
-#endif
- return 1;
- }
- }
- while (max > 0);
-
-#ifdef DEBUG_SCAVENGING
- printf("scavenging failed\n");
- fz_print_store(ctx, stderr);
- Memento_listBlocks();
-#endif
- return 0;
-}