From 4d1b28c393fd8ccf7fb8b1e485e371caedec9605 Mon Sep 17 00:00:00 2001
From: Kenichi Ishigaki <ishigaki@cpan.org>
Date: Sun, 6 Dec 2020 02:00:27 +0900
Subject: [PATCH] Expose sqlite3_txn_state

---
 SQLite.xs         | 11 +++++++++++
 dbdimp.c          | 15 +++++++++++++++
 dbdimp.h          |  1 +
 lib/DBD/SQLite.pm |  9 +++++++++
 t/67_txn_state.t  | 41 +++++++++++++++++++++++++++++++++++++++++
 5 files changed, 77 insertions(+)
 create mode 100644 t/67_txn_state.t

diff --git a/SQLite.xs b/SQLite.xs
index 122de79..48f113d 100644
--- a/SQLite.xs
+++ b/SQLite.xs
@@ -380,6 +380,17 @@ get_autocommit(dbh)
     OUTPUT:
         RETVAL
 
+static int
+txn_state(SV* dbh, SV *schema = &PL_sv_undef)
+    ALIAS:
+        DBD::SQLite::db::sqlite_txn_state = 1
+    CODE:
+    {
+        RETVAL = sqlite_db_txn_state(aTHX_ dbh, schema);
+    }
+    OUTPUT:
+        RETVAL
+
 MODULE = DBD::SQLite          PACKAGE = DBD::SQLite::st
 
 PROTOTYPES: DISABLE
diff --git a/dbdimp.c b/dbdimp.c
index ef492a7..0165dcb 100644
--- a/dbdimp.c
+++ b/dbdimp.c
@@ -2851,6 +2851,21 @@ sqlite_db_get_autocommit(pTHX_ SV *dbh)
     return sqlite3_get_autocommit(imp_dbh->db);
 }
 
+int
+sqlite_db_txn_state(pTHX_ SV *dbh, SV *schema)
+{
+#if SQLITE_VERSION_NUMBER >= 3034000
+    D_imp_dbh(dbh);
+    if (SvOK(schema) && SvPOK(schema)) {
+        return sqlite3_txn_state(imp_dbh->db, SvPV_nolen(schema));
+    } else {
+        return sqlite3_txn_state(imp_dbh->db, NULL);
+    }
+#else
+    return -1;
+#endif
+}
+
 #include "dbdimp_tokenizer.inc"
 #include "dbdimp_virtual_table.inc"
 
diff --git a/dbdimp.h b/dbdimp.h
index 3f5cc54..04d2b00 100644
--- a/dbdimp.h
+++ b/dbdimp.h
@@ -137,6 +137,7 @@ int sqlite_db_create_module(pTHX_ SV *dbh, const char *name, const char *perl_cl
 int sqlite_db_limit(pTHX_ SV *dbh, int id, int new_value);
 int sqlite_db_config(pTHX_ SV *dbh, int id, int new_value);
 int sqlite_db_get_autocommit(pTHX_ SV *dbh);
+int sqlite_db_txn_state(pTHX_ SV *dbh, SV *schema);
 int sqlite_db_do_sv(SV *dbh, imp_dbh_t *imp_dbh, SV *sv_statement);
 void init_cxt();
 
diff --git a/lib/DBD/SQLite.pm b/lib/DBD/SQLite.pm
index 1b6f38c..0ed70e8 100644
--- a/lib/DBD/SQLite.pm
+++ b/lib/DBD/SQLite.pm
@@ -61,6 +61,7 @@ sub driver {
         DBD::SQLite::db->install_method('sqlite_limit');
         DBD::SQLite::db->install_method('sqlite_db_config');
         DBD::SQLite::db->install_method('sqlite_get_autocommit');
+        DBD::SQLite::db->install_method('sqlite_txn_state');
 
         $methods_are_installed++;
     }
@@ -2374,6 +2375,14 @@ Returns true if the internal SQLite connection is in an autocommit mode.
 This does not always return the same value as C<< $dbh->{AutoCommit} >>.
 This returns false if you explicitly issue a C<<BEGIN>> statement.
 
+=head2 $dbh->sqlite_txn_state()
+
+Returns the internal transaction status of SQLite (not of DBI).
+Return values (SQLITE_TXN_NONE, SQLITE_TXN_READ, SQLITE_TXN_WRITE)
+can be imported from DBD::SQLite::Constants. You may pass an optional
+schema name (usually "main"). If SQLite does not support this function,
+or if you pass a wrong schema name, -1 is returned.
+
 =head1 DRIVER FUNCTIONS
 
 =head2 DBD::SQLite::compile_options()
diff --git a/t/67_txn_state.t b/t/67_txn_state.t
new file mode 100644
index 0000000..b4f8c2f
--- /dev/null
+++ b/t/67_txn_state.t
@@ -0,0 +1,41 @@
+use strict;
+use warnings;
+use lib "t/lib";
+use SQLiteTest qw/connect_ok @CALL_FUNCS/;
+use Test::More;
+use if -d ".git", "Test::FailWarnings";
+use DBD::SQLite::Constants ':allowed_return_values_from_sqlite3_txn_state';
+
+note "test main schema";
+test('main');
+note "test undef schema";
+test(undef);
+note "omit schema";
+test();
+done_testing;
+
+sub test {
+    my @schema = @_;
+    die if @schema > 1;
+
+    for my $func (@CALL_FUNCS) {
+        my $dbh = connect_ok(PrintError => 0, RaiseError => 1);
+        $dbh->do('create table foo (id)');
+
+        my $txn_state = $dbh->$func(@schema, 'txn_state');
+        is $txn_state => SQLITE_TXN_NONE, "internal transaction is none";
+
+        $dbh->do('BEGIN');
+
+        my $row = $dbh->selectrow_arrayref('SELECT * FROM foo');
+
+        $txn_state = $dbh->$func(@schema, 'txn_state');
+        is $txn_state => SQLITE_TXN_READ, "internal transaction is read";
+
+        $dbh->do('insert into foo values (1)');
+        $txn_state = $dbh->$func(@schema, 'txn_state');
+        is $txn_state => SQLITE_TXN_WRITE, "internal transaction is write";
+
+        $dbh->commit;
+    }
+}