hashtable: Add ht_walk

This is obviously linear, but at least there's a bailout. And we expect
the hash tables this will be called on will be small.

Signed-off-by: Adam Jackson <ajax@redhat.com>

2 files changed, 18 insertions, 0 deletions

diff --git a/Xext/hashtable.c b/Xext/hashtable.c
index 41b2e0013..e8477a11b 100644
--- a/Xext/hashtable.c
+++ b/Xext/hashtable.c
@@ -83,6 +83,20 @@ ht_destroy(HashTable ht)
     free(ht->buckets);
 }
 
+void
+ht_walk(HashTable ht, int (*callback)(void *key, void *data, void *c), void *c)
+{
+    int i;
+    BucketPtr it, tmp;
+    int numBuckets = 1 << ht->bucketBits;
+    for (i = 0; i < numBuckets; ++i) {
+        xorg_list_for_each_entry_safe(it, tmp, &ht->buckets[i], l) {
+            if (callback(it->key, it->data, c))
+                return;
+        }
+    }
+}
+
 static Bool
 double_size(HashTable ht)
 {
diff --git a/Xext/hashtable.h b/Xext/hashtable.h
index a988af32c..db0b63935 100644
--- a/Xext/hashtable.h
+++ b/Xext/hashtable.h
@@ -134,4 +134,8 @@ extern _X_EXPORT int ht_resourceid_compare(void *cdata,
                                            const void *a,
                                            const void *b);
 
+/** @brief  Calls the callback function for every element of the hash table. */
+extern _X_EXPORT void
+ht_walk(HashTable ht, int (*callback)(void *key, void *data, void *c), void *c);
+
 #endif // HASHTABLE_H