X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=ovsdb%2Flog.c;h=f0926c0e6d976c138ffe3b16867323f7e47514a4;hb=81fe12a77582f063f97e75f86b5f10e97dfbcaeb;hp=09b9f1f7adc809c2eb6dcb1fcac13bed428f7568;hpb=3762274e6359f4afe04107851f4c71347fa0afa0;p=sliver-openvswitch.git

diff --git a/ovsdb/log.c b/ovsdb/log.c
index 09b9f1f7a..f0926c0e6 100644
--- a/ovsdb/log.c
+++ b/ovsdb/log.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2009, 2010 Nicira Networks
+/* Copyright (c) 2009, 2010, 2011 Nicira Networks
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,16 +33,17 @@
 #include "socket-util.h"
 #include "transaction.h"
 #include "util.h"
-
-#define THIS_MODULE VLM_ovsdb_log
 #include "vlog.h"
 
+VLOG_DEFINE_THIS_MODULE(ovsdb_log);
+
 enum ovsdb_log_mode {
     OVSDB_LOG_READ,
     OVSDB_LOG_WRITE
 };
 
 struct ovsdb_log {
+    off_t prev_offset;
     off_t offset;
     char *name;
     struct lockfile *lockfile;
@@ -121,6 +122,7 @@ ovsdb_log_open(const char *name, enum ovsdb_log_open_mode open_mode,
     file->name = xstrdup(name);
     file->lockfile = lockfile;
     file->stream = stream;
+    file->prev_offset = 0;
     file->offset = 0;
     file->read_error = NULL;
     file->write_error = NULL;
@@ -284,9 +286,10 @@ ovsdb_log_read(struct ovsdb_log *file, struct json **jsonp)
         goto error;
     }
 
+    file->prev_offset = file->offset;
     file->offset = data_offset + data_length;
     *jsonp = json;
-    return 0;
+    return NULL;
 
 error:
     file->read_error = ovsdb_error_clone(error);
@@ -294,6 +297,22 @@ error:
     return error;
 }
 
+/* Causes the log record read by the previous call to ovsdb_log_read() to be
+ * effectively discarded.  The next call to ovsdb_log_write() will overwrite
+ * that previously read record.
+ *
+ * Calling this function more than once has no additional effect.
+ *
+ * This function is useful when ovsdb_log_read() successfully reads a record
+ * but that record does not make sense at a higher level (e.g. it specifies an
+ * invalid transaction). */
+void
+ovsdb_log_unread(struct ovsdb_log *file)
+{
+    assert(file->mode == OVSDB_LOG_READ);
+    file->offset = file->prev_offset;
+}
+
 struct ovsdb_error *
 ovsdb_log_write(struct ovsdb_log *file, struct json *json)
 {
@@ -353,7 +372,7 @@ ovsdb_log_write(struct ovsdb_log *file, struct json *json)
 
     file->offset += strlen(header) + length;
     free(json_string);
-    return 0;
+    return NULL;
 
 error:
     file->write_error = ovsdb_error_clone(error);
@@ -367,7 +386,7 @@ ovsdb_log_commit(struct ovsdb_log *file)
     if (fsync(fileno(file->stream))) {
         return ovsdb_io_error(errno, "%s: fsync failed", file->name);
     }
-    return 0;
+    return NULL;
 }
 
 /* Returns the current offset into the file backing 'log', in bytes.  This