[libvirt] [PATCH v2 1/5] Introduce virHashAtomic

[Jiri Denemark]

This is a self-locking wrapper around virHashTable. Only a limited set
of APIs are implemented now (the ones which are used in the following
patch) as more can be added on demand.

Signed-off-by: Jiri Denemark <jdene...@redhat.com>
---

Notes:
    Version 2:
    - s/virHashLockable/virHashAtomic/

 src/libvirt_private.syms |  3 ++
 src/util/virhash.c       | 81 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/util/virhash.h       | 10 ++++++
 3 files changed, 94 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 720afdf..65168b1 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1476,6 +1476,9 @@ virFirewallStartTransaction;
 
 # util/virhash.h
 virHashAddEntry;
+virHashAtomicNew;
+virHashAtomicSteal;
+virHashAtomicUpdate;
 virHashCreate;
 virHashEqual;
 virHashForEach;
diff --git a/src/util/virhash.c b/src/util/virhash.c
index e3c1880..3cfcc69 100644
--- a/src/util/virhash.c
+++ b/src/util/virhash.c
@@ -31,6 +31,7 @@
 #include "virhashcode.h"
 #include "virrandom.h"
 #include "virstring.h"
+#include "virobject.h"
 
 #define VIR_FROM_THIS VIR_FROM_NONE
 
@@ -76,6 +77,28 @@ struct _virHashTable {
     virHashKeyFree keyFree;
 };
 
+struct _virHashAtomic {
+    virObjectLockable parent;
+    virHashTablePtr hash;
+};
+
+static virClassPtr virHashAtomicClass;
+static void virHashAtomicDispose(void *obj);
+
+static int virHashAtomicOnceInit(void)
+{
+    virHashAtomicClass = virClassNew(virClassForObjectLockable(),
+                                     "virHashAtomic",
+                                     sizeof(virHashAtomic),
+                                     virHashAtomicDispose);
+    if (!virHashAtomicClass)
+        return -1;
+    else
+        return 0;
+}
+VIR_ONCE_GLOBAL_INIT(virHashAtomic)
+
+
 static uint32_t virHashStrCode(const void *name, uint32_t seed)
 {
     return virHashCodeGen(name, strlen(name), seed);
@@ -178,6 +201,36 @@ virHashTablePtr virHashCreate(ssize_t size, 
virHashDataFree dataFree)
                              virHashStrFree);
 }
 
+
+virHashAtomicPtr
+virHashAtomicNew(ssize_t size,
+                 virHashDataFree dataFree)
+{
+    virHashAtomicPtr hash;
+
+    if (virHashAtomicInitialize() < 0)
+        return NULL;
+
+    if (!(hash = virObjectLockableNew(virHashAtomicClass)))
+        return NULL;
+
+    if (!(hash->hash = virHashCreate(size, dataFree))) {
+        virObjectUnref(hash);
+        return NULL;
+    }
+    return hash;
+}
+
+
+static void
+virHashAtomicDispose(void *obj)
+{
+    virHashAtomicPtr hash = obj;
+
+    virHashFree(hash->hash);
+}
+
+
 /**
  * virHashGrow:
  * @table: the hash table
@@ -360,6 +413,21 @@ virHashUpdateEntry(virHashTablePtr table, const void *name,
     return virHashAddOrUpdateEntry(table, name, userdata, true);
 }
 
+int
+virHashAtomicUpdate(virHashAtomicPtr table,
+                    const void *name,
+                    void *userdata)
+{
+    int ret;
+
+    virObjectLock(table);
+    ret = virHashAddOrUpdateEntry(table->hash, name, userdata, true);
+    virObjectUnlock(table);
+
+    return ret;
+}
+
+
 /**
  * virHashLookup:
  * @table: the hash table
@@ -409,6 +477,19 @@ void *virHashSteal(virHashTablePtr table, const void *name)
     return data;
 }
 
+void *
+virHashAtomicSteal(virHashAtomicPtr table,
+                   const void *name)
+{
+    void *data;
+
+    virObjectLock(table);
+    data = virHashSteal(table->hash, name);
+    virObjectUnlock(table);
+
+    return data;
+}
+
 
 /**
  * virHashSize:
diff --git a/src/util/virhash.h b/src/util/virhash.h
index a137137..50b9a04 100644
--- a/src/util/virhash.h
+++ b/src/util/virhash.h
@@ -21,6 +21,9 @@
 typedef struct _virHashTable virHashTable;
 typedef virHashTable *virHashTablePtr;
 
+typedef struct _virHashAtomic virHashAtomic;
+typedef virHashAtomic *virHashAtomicPtr;
+
 /*
  * function types:
  */
@@ -101,6 +104,8 @@ typedef void (*virHashKeyFree)(void *name);
  */
 virHashTablePtr virHashCreate(ssize_t size,
                               virHashDataFree dataFree);
+virHashAtomicPtr virHashAtomicNew(ssize_t size,
+                                  virHashDataFree dataFree);
 virHashTablePtr virHashCreateFull(ssize_t size,
                                   virHashDataFree dataFree,
                                   virHashKeyCode keyCode,
@@ -119,6 +124,9 @@ int virHashAddEntry(virHashTablePtr table,
 int virHashUpdateEntry(virHashTablePtr table,
                        const void *name,
                        void *userdata);
+int virHashAtomicUpdate(virHashAtomicPtr table,
+                        const void *name,
+                        void *userdata);
 
 /*
  * Remove an entry from the hash table.
@@ -140,6 +148,8 @@ void *virHashLookup(const virHashTable *table, const void 
*name);
  * Retrieve & remove the userdata.
  */
 void *virHashSteal(virHashTablePtr table, const void *name);
+void *virHashAtomicSteal(virHashAtomicPtr table,
+                         const void *name);
 
 /*
  * Get the hash table's key/value pairs and have them optionally sorted.
-- 
2.4.5

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