Fix Amazon S3 store_lookup_last implementation.

[bluesky.git] / bluesky / util.c

diff --git a/bluesky/util.c b/bluesky/util.c
index 2e6f0aa..d292634 100644 (file)
--- a/bluesky/util.c
+++ b/bluesky/util.c
@@ -10,6 +10,7 @@
 #include <stdint.h>
 #include <glib.h>
 #include <string.h>
+#include <sys/mman.h>
 
 #include "bluesky-private.h"
 
@@ -36,6 +37,20 @@ gchar *bluesky_lowercase(const gchar *s)
     return g_ascii_strdown(s, -1);
 }
 
+gboolean bluesky_inode_is_ready(BlueSkyInode *inode)
+{
+    if (inode == NULL)
+        return FALSE;
+
+    g_mutex_lock(inode->lock);
+    gboolean valid = (inode->type != BLUESKY_PENDING
+                      && inode->type != BLUESKY_INVALID);
+
+    g_mutex_unlock(inode->lock);
+
+    return valid;
+}
+
 /**** Reference-counted strings. ****/
 
 /* Create and return a new reference-counted string.  The reference count is
@@ -45,6 +60,7 @@ gchar *bluesky_lowercase(const gchar *s)
 BlueSkyRCStr *bluesky_string_new(gpointer data, gsize len)
 {
     BlueSkyRCStr *string = g_new(BlueSkyRCStr, 1);
+    string->mmap = NULL;
     string->data = data;
     string->len = len;
     g_atomic_int_set(&string->refcount, 1);
@@ -58,6 +74,21 @@ BlueSkyRCStr *bluesky_string_new_from_gstring(GString *s)
     return bluesky_string_new(g_string_free(s, FALSE), len);
 }
 
+/* Create a new BlueSkyRCStr from a memory-mapped buffer. */
+BlueSkyRCStr *bluesky_string_new_from_mmap(BlueSkyCacheFile *mmap,
+                                           int offset, gsize len)
+{
+    g_assert(offset + len <= mmap->len);
+
+    BlueSkyRCStr *string = g_new(BlueSkyRCStr, 1);
+    string->mmap = mmap;
+    g_atomic_int_inc(&mmap->mapcount);
+    string->data = (char *)mmap->addr + offset;
+    string->len = len;
+    g_atomic_int_set(&string->refcount, 1);
+    return string;
+}
+
 void bluesky_string_ref(BlueSkyRCStr *string)
 {
     if (string == NULL)
@@ -72,7 +103,11 @@ void bluesky_string_unref(BlueSkyRCStr *string)
         return;
 
     if (g_atomic_int_dec_and_test(&string->refcount)) {
-        g_free(string->data);
+        if (string->mmap == NULL) {
+            g_free(string->data);
+        } else {
+            bluesky_mmap_unref(string->mmap);
+        }
         g_free(string);
     }
 }
@@ -88,6 +123,14 @@ BlueSkyRCStr *bluesky_string_dup(BlueSkyRCStr *string)
     if (string == NULL)
         return NULL;
 
+    if (string->mmap != NULL) {
+        BlueSkyRCStr *s;
+        s = bluesky_string_new(g_memdup(string->data, string->len),
+                               string->len);
+        bluesky_string_unref(string);
+        return s;
+    }
+
     if (g_atomic_int_dec_and_test(&string->refcount)) {
         /* There are no other shared copies, so return this one. */
         g_atomic_int_inc(&string->refcount);
@@ -105,6 +148,8 @@ BlueSkyRCStr *bluesky_string_dup(BlueSkyRCStr *string)
  * if needed). */
 void bluesky_string_resize(BlueSkyRCStr *string, gsize len)
 {
+    g_assert(string->mmap == NULL);
+
     if (string->len == len)
         return;
 
@@ -113,3 +158,64 @@ void bluesky_string_resize(BlueSkyRCStr *string, gsize len)
     string->data = g_realloc(string->data, len);
     string->len = len;
 }
+
+/* Cache LRU list management functions.  These manage the doubly-linked list of
+ * inodes sorted by accessed/modified time.  The FS lock should be held while
+ * calling these.
+ *
+ * _remove will unlink an inode from the linked list.
+ *
+ * _prepend and _append insert an inode at the head or tail of the linked list,
+ * and return a pointer to the linked list element (which should be stored in
+ * the inode); the inode should not already be in the list.
+ *
+ * _head and _tail simply return the first or last item inode in the list. */
+void bluesky_list_unlink(GList *head, GList *item)
+{
+    if (item == NULL)
+        return;
+
+    if (head->prev == item)
+        head->prev = item->prev;
+    head->next = g_list_delete_link(head->next, item);
+}
+
+GList *bluesky_list_prepend(GList *head, BlueSkyInode *inode)
+{
+    head->next = g_list_prepend(head->next, inode);
+    if (head->prev == NULL)
+        head->prev = g_list_last(head->next);
+    return head->next;
+}
+
+GList *bluesky_list_append(GList *head, BlueSkyInode *inode)
+{
+    if (head->next == NULL)
+        return bluesky_list_prepend(head, inode);
+
+    g_assert(head->prev != NULL && head->prev->next == NULL);
+
+    GList *link = g_list_alloc();
+    link->data = inode;
+    link->next = NULL;
+    link->prev = head->prev;
+    head->prev->next = link;
+    head->prev = link;
+    return link;
+}
+
+BlueSkyInode *bluesky_list_head(GList *head)
+{
+    if (head->next == NULL)
+        return NULL;
+    else
+        return (BlueSkyInode *)head->next->data;
+}
+
+BlueSkyInode *bluesky_list_tail(GList *head)
+{
+    if (head->prev == NULL)
+        return NULL;
+    else
+        return (BlueSkyInode *)head->prev->data;
+}