[gnunet] 01/08: NAMESTORE: Start transactional API

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martin-schanzenbach pushed a commit to branch master
in repository gnunet.

commit e1d8213bb3264ef384af84d01b0ad05f7911f829
Author: Martin Schanzenbach <schanzen@gnunet.org>
AuthorDate: Thu Sep 22 00:13:52 2022 +0900

    NAMESTORE: Start transactional API
---
 src/include/gnunet_namestore_plugin.h   | 52 ++++++---------------------
 src/namestore/plugin_namestore_sqlite.c | 63 ++++++++++++++++++++++++++++++---
 2 files changed, 69 insertions(+), 46 deletions(-)

diff --git a/src/include/gnunet_namestore_plugin.h 
b/src/include/gnunet_namestore_plugin.h
index 9301c29fe..82bac1f9e 100644
--- a/src/include/gnunet_namestore_plugin.h
+++ b/src/include/gnunet_namestore_plugin.h
@@ -160,63 +160,31 @@ struct GNUNET_NAMESTORE_PluginFunctions
    * Start a transaction in the database
    *
    * @param cls closure (internal context for the plugin)
-   * @return #GNUNET_OK on success, #GNUNET_NO if there were no results, 
#GNUNET_SYSERR on error
+   * @param emsg message. On error, string will be allocated and must be freed.
+   * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
    */
   enum GNUNET_GenericReturnValue
-  (*transaction_begin) (void *cls);
+  (*transaction_begin) (void *cls, char **emsg);
 
   /**
-   * Abort a transaction in the database
+   * Abort and roll back a transaction in the database
    *
    * @param cls closure (internal context for the plugin)
-   * @return #GNUNET_OK on success, #GNUNET_NO if there were no results, 
#GNUNET_SYSERR on error
+   * @param emsg message. On error, string will be allocated and must be freed.
+   * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
    */
   enum GNUNET_GenericReturnValue
-  (*transaction_abort) (void *cls);
+  (*transaction_rollback) (void *cls, char **emsg);
 
   /**
    * Commit a transaction in the database
    *
    * @param cls closure (internal context for the plugin)
-   * @return #GNUNET_OK on success, #GNUNET_NO if there were no results, 
#GNUNET_SYSERR on error
+   * @param emsg message. On error, string will be allocated and must be freed.
+   * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
    */
   enum GNUNET_GenericReturnValue
-  (*transaction_commit) (void *cls);
-
-  /**
-   * Replace a record in the datastore for which we are the authority.
-   * Removes any existing record in the same zone with the same name.
-   *
-   * @param cls closure (internal context for the plugin)
-   * @param zone private key of the zone
-   * @param label name of the record in the zone
-   * @param rd_count number of entries in @a rd array, 0 to delete all records
-   * @param rd array of records with data to store
-   * @return #GNUNET_OK on success, else #GNUNET_SYSERR
-   */
-  int
-  (*replace_records) (void *cls,
-                    const struct GNUNET_IDENTITY_PrivateKey *zone,
-                    const char *label,
-                    unsigned int rd_count,
-                    const struct GNUNET_GNSRECORD_Data *rd);
-
-  /**
-   * Lookup records in the datastore for which we are the authority.
-   *
-   * @param cls closure (internal context for the plugin)
-   * @param zone private key of the zone
-   * @param label name of the record in the zone
-   * @param iter function to call with the result
-   * @param iter_cls closure for @a iter
-   * @return #GNUNET_OK on success, #GNUNET_NO for no results, else 
#GNUNET_SYSERR
-   */
-  int
-  (*select_records) (void *cls,
-                     const struct GNUNET_IDENTITY_PrivateKey *zone,
-                     const char *label,
-                     GNUNET_NAMESTORE_RecordIterator iter,
-                     void *iter_cls);
+  (*transaction_commit) (void *cls, char **emsg);
 
 };
 
diff --git a/src/namestore/plugin_namestore_sqlite.c 
b/src/namestore/plugin_namestore_sqlite.c
index 0b3aac84f..f2017b695 100644
--- a/src/namestore/plugin_namestore_sqlite.c
+++ b/src/namestore/plugin_namestore_sqlite.c
@@ -331,8 +331,8 @@ namestore_sqlite_store_records (void *cls,
   for (unsigned int i = 0; i < rd_count; i++)
   {
     LOG (GNUNET_ERROR_TYPE_DEBUG,
-       "Checking if `%d' is zonekey type\n",
-       rd[i].record_type);
+         "Checking if `%d' is zonekey type\n",
+         rd[i].record_type);
 
     if (GNUNET_YES == GNUNET_GNSRECORD_is_zonekey_type (rd[i].record_type))
     {
@@ -342,8 +342,8 @@ namestore_sqlite_store_records (void *cls,
                                                          rd[i].record_type,
                                                          &pkey));
       LOG (GNUNET_ERROR_TYPE_DEBUG,
-       "Storing delegation zone record value `%s'\n",
-       GNUNET_GNSRECORD_z2s (&pkey));
+           "Storing delegation zone record value `%s'\n",
+           GNUNET_GNSRECORD_z2s (&pkey));
 
       break;
     }
@@ -740,6 +740,58 @@ namestore_sqlite_zone_to_name (void *cls,
                                         iter_cls);
 }
 
+/**
+ * Begin a transaction for a client.
+ * This locks the database. SQLite is unable to discern between different
+ * rows with a specific zone key but the API looks like this anyway.
+ * https://www.sqlite.org/lang_transaction.html
+ *
+ * @param cls closure (internal context for the plugin)
+ * @param emsg error message set of return code is #GNUNET_SYSERR
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR if transaction cannot be 
started.
+ */
+static enum GNUNET_GenericReturnValue
+namestore_sqlite_transaction_begin (void *cls,
+                                    char **emsg)
+{
+  struct Plugin *plugin = cls;
+  return (SQLITE_BUSY == sqlite3_exec (plugin->dbh, "BEGIN TRANSACTION;", NULL,
+                                       NULL, emsg)) ? GNUNET_SYSERR : 
GNUNET_OK;
+}
+
+/**
+ * Commit a transaction for a client.
+ * This releases the lock on the database.
+ *
+ * @param cls closure (internal context for the plugin)
+ * @param emsg error message set of return code is #GNUNET_SYSERR
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR if transaction cannot be 
started.
+ */
+static enum GNUNET_GenericReturnValue
+namestore_sqlite_transaction_rollback (void *cls,
+                                       char **emsg)
+{
+  struct Plugin *plugin = cls;
+  return (SQLITE_BUSY == sqlite3_exec (plugin->dbh, "ROLLBACK;", NULL,
+                                       NULL, emsg)) ? GNUNET_SYSERR : 
GNUNET_OK;
+}
+
+/**
+ * Roll back a transaction for a client.
+ * This releases the lock on the database.
+ *
+ * @param cls closure (internal context for the plugin)
+ * @param emsg error message set of return code is #GNUNET_SYSERR
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR if transaction cannot be 
started.
+ */
+static enum GNUNET_GenericReturnValue
+namestore_sqlite_transaction_commit (void *cls,
+                                     char **emsg)
+{
+  struct Plugin *plugin = cls;
+  return (SQLITE_BUSY == sqlite3_exec (plugin->dbh, "END TRANSACTION;", NULL,
+                                       NULL, emsg)) ? GNUNET_SYSERR : 
GNUNET_OK;
+}
 
 /**
  * Entry point for the plugin.
@@ -771,6 +823,9 @@ libgnunet_plugin_namestore_sqlite_init (void *cls)
   api->iterate_records = &namestore_sqlite_iterate_records;
   api->zone_to_name = &namestore_sqlite_zone_to_name;
   api->lookup_records = &namestore_sqlite_lookup_records;
+  api->transaction_begin = &namestore_sqlite_transaction_begin;
+  api->transaction_commit = &namestore_sqlite_transaction_commit;
+  api->transaction_rollback = &namestore_sqlite_transaction_rollback;
   LOG (GNUNET_ERROR_TYPE_INFO,
        _ ("Sqlite database running\n"));
   return api;

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