[DBD-SQLite] [PATCH] Add online backup support

[Kenichi Ishigaki]

Hi Toby, please write a test if you can.

As for the usage of install_method(), we need to do like this:

  DBD::SQLite::db->install_method('sqlite_your_function_name');

Best,

Kenichi


On Tue, 05 May 2009 12:11:56 +1000, Toby Corkindale <toby.corkindale at strategicdata.com.au> wrote:

>Tim Bunce wrote:
>> Great, but please don't use the old func() interface.  It's *much*
>> better for the driver to call install_method() when it loads.
>> Then applications can invoke the methods directly, without having
>> to use func(). As a bonus, RaiseError etc work with install_method()
>> but not with func().
>>
>> Either way, driver-private methods should begin with the driver's
>> prefix, 'sqlite_' in this case.
>
>Hi Tim,
>Thanks for the feedback.
>I'm not entirely sure I'm Doing It Right, but attached is a different
>patch against trunk, which uses the install_method() method of
>installing functions.
>
>It works, but produces a warning that "backup_ is not a registered
>driver prefix". However if i add "sqlite_" to the front, then I get an
>error that sqlite_backup_from_file() cannot be found.
>Although the new methods inside dbdimp.c and SQLite.xs all do have that
>prefix.
>
>Could you suggest what I have done wrong?
>
>thanks,
>Toby

>Patch to add support for SQLite's Online Backup functions.
>Signed off by Toby Corkindale <TJC at cpan.org>
>
> SQLite.xs         |   19 ++++++++++++++++++
> dbdimp.c          |   56 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> dbdimp.h          |    2 +
> lib/DBD/SQLite.pm |   16 +++++++++++++++
> 4 files changed, 93 insertions(+), 0 deletions(-)
>
>diff --git a/SQLite.xs b/SQLite.xs
>index fda00aa..8e9d0a6 100644
>--- a/SQLite.xs
>+++ b/SQLite.xs
>@@ -92,6 +92,25 @@ busy_timeout(dbh, timeout=0)
>   OUTPUT:
>     RETVAL
>
>+int
>+sqlite_backup_from_file(dbh, filename)
>+  SV *dbh
>+  char *filename
>+  CODE:
>+    RETVAL = _sqlite_backup_from_file(aTHX_ dbh, filename);
>+  OUTPUT:
>+    RETVAL
>+
>+int
>+sqlite_backup_to_file(dbh, filename)
>+  SV *dbh
>+  char *filename
>+  CODE:
>+    RETVAL = _sqlite_backup_to_file(aTHX_ dbh, filename);
>+  OUTPUT:
>+    RETVAL
>+
>+
> MODULE = DBD::SQLite          PACKAGE = DBD::SQLite::st
>
> PROTOTYPES: DISABLE
>diff --git a/dbdimp.c b/dbdimp.c
>index 89a531e..cce3e30 100644
>--- a/dbdimp.c
>+++ b/dbdimp.c
>@@ -139,6 +139,62 @@ dbd_set_sqlite3_busy_timeout (pTHX_ SV *dbh, int timeout )
>   return imp_dbh->timeout;
> }
>
>+/* Accesses the SQLite Online Backup API, and fills the currently loaded
>+ * database from the passed filename.
>+ * Usual usage of this would be when you're operating on the :memory:
>+ * special database connection and want to copy it in from a real db.
>+ */
>+int
>+_sqlite_backup_from_file(pTHX_ SV *dbh, char *filename)
>+{
>+    int rc;
>+    sqlite3 *pFrom;
>+    sqlite3_backup *pBackup;
>+
>+    D_imp_dbh(dbh);
>+
>+    rc = sqlite3_open(filename, &pFrom);
>+    if (rc==SQLITE_OK) {
>+
>+        pBackup = sqlite3_backup_init(imp_dbh->db, "main", pFrom, "main");
>+        if (pBackup) {
>+            (void)sqlite3_backup_step(pBackup, -1);
>+            (void)sqlite3_backup_finish(pBackup);
>+        }
>+        rc = sqlite3_errcode(imp_dbh->db);
>+        (void)sqlite3_close(pFrom);
>+    }
>+    return rc;
>+}
>+
>+/* Accesses the SQLite Online Backup API, and copies the currently loaded
>+ * database into the passed filename.
>+ * Usual usage of this would be when you're operating on the :memory:
>+ * special database connection, and want to back it up to an on-disk file.
>+ */
>+int
>+_sqlite_backup_to_file(pTHX_ SV *dbh, char *filename)
>+{
>+    int rc;
>+    sqlite3 *pTo;
>+    sqlite3_backup *pBackup;
>+
>+    D_imp_dbh(dbh);
>+
>+    rc = sqlite3_open(filename, &pTo);
>+    if (rc==SQLITE_OK) {
>+
>+        pBackup = sqlite3_backup_init(pTo, "main", imp_dbh->db, "main");
>+        if (pBackup) {
>+            (void)sqlite3_backup_step(pBackup, -1);
>+            (void)sqlite3_backup_finish(pBackup);
>+        }
>+        rc = sqlite3_errcode(pTo);
>+        (void)sqlite3_close(pTo);
>+    }
>+    return rc;
>+}
>+
> int
> sqlite_db_disconnect (SV *dbh, imp_dbh_t *imp_dbh)
> {
>diff --git a/dbdimp.h b/dbdimp.h
>index 78f7c5e..dea1bcd 100644
>--- a/dbdimp.h
>+++ b/dbdimp.h
>@@ -79,6 +79,8 @@ void sqlite3_db_progress_handler(pTHX_ SV *dbh, int n_opcodes, SV *handler);
> void sqlite_st_reset(pTHX_ SV *sth );
> int sqlite_bind_col( SV *sth, imp_sth_t *imp_sth, SV *col, SV *ref, IV sql_type, SV *attribs );
> int dbd_set_sqlite3_busy_timeout (pTHX_ SV *dbh, int timeout );
>+int _sqlite_backup_from_file(pTHX_ SV *dbh, char *filename);
>+int _sqlite_backup_to_file(pTHX_ SV *dbh, char *filename);
>
> #ifdef SvUTF8_on
>
>diff --git a/lib/DBD/SQLite.pm b/lib/DBD/SQLite.pm
>index 3e6219a..122cd14 100644
>--- a/lib/DBD/SQLite.pm
>+++ b/lib/DBD/SQLite.pm
>@@ -98,6 +98,10 @@ sub connect {
>         $attr->{Warn} = 0;
>     }
>
>+    # Install online backup private methods:
>+    DBD::SQLite::db->install_method('backup_from_file', {});
>+    DBD::SQLite::db->install_method('backup_to_file', {});
>+
>     return $dbh;
> }
>
>@@ -723,6 +727,18 @@ progress handler.
>
> =back
>
>+=head2 $dbh->backup_from_file( $filename )
>+
>+This method accesses the SQLite Online Backup API, and will take a backup of
>+the named database file, copying it to, and overwriting, your current database
>+connection. This can be particularly handy if your current connection is to the
>+special :memory: database, and you wish to populate it from an existing DB.
>+
>+=head2 $dbh->backup_to_file( $filename )
>+
>+This method accesses the SQLite Online Backup API, and will take a backup of
>+the currently connected database, and write it out to the named file.
>+
> =head1 BLOBS
>
> As of version 1.11, blobs should "just work" in SQLite as text columns.

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