unix-ffi/sqlite3: Change to use close and prepare v2 versions, clean-up.

The sqlite3_prepare and sqlite3_close have been changed to use the v2
version. For the prepare this was done as the v1 version is "legacy",
and for close the documentation describes the v2 version to be used for
"host languages that are garbage collected, and where the order in
which destructors are called is arbitrary", which fits here.

Some clean-up to comments has also be done, and the tests now also
close the Cursor and Connections.

Signed-off-by: Robert Klink <rhermanklink@ripe.net>

unix-ffi/sqlite3/sqlite3.py

@@ -5,11 +5,15 @@ import uctypes
 
 sq3 = ffilib.open("libsqlite3")
 
+# int sqlite3_open(
+#  const char *filename,   /* Database filename (UTF-8) */
+#  sqlite3 **ppDb          /* OUT: SQLite db handle */
+# );
 sqlite3_open = sq3.func("i", "sqlite3_open", "sp")
 # int sqlite3_config(int, ...);
 sqlite3_config = sq3.func("i", "sqlite3_config", "ii")
-# int sqlite3_close(sqlite3*);
-sqlite3_close = sq3.func("i", "sqlite3_close", "p")
+# int sqlite3_close_v2(sqlite3*);
+sqlite3_close = sq3.func("i", "sqlite3_close_v2", "p")
 # int sqlite3_prepare(
 #  sqlite3 *db,            /* Database handle */
 #  const char *zSql,       /* SQL statement, UTF-8 encoded */
@@ -17,7 +21,7 @@ sqlite3_close = sq3.func("i", "sqlite3_close", "p")
 #  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
 #  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
 # );
-sqlite3_prepare = sq3.func("i", "sqlite3_prepare", "psipp")
+sqlite3_prepare = sq3.func("i", "sqlite3_prepare_v2", "psipp")
 # int sqlite3_finalize(sqlite3_stmt *pStmt);
 sqlite3_finalize = sq3.func("i", "sqlite3_finalize", "p")
 # int sqlite3_step(sqlite3_stmt*);
@@ -26,20 +30,17 @@ sqlite3_step = sq3.func("i", "sqlite3_step", "p")
 sqlite3_column_count = sq3.func("i", "sqlite3_column_count", "p")
 # int sqlite3_column_type(sqlite3_stmt*, int iCol);
 sqlite3_column_type = sq3.func("i", "sqlite3_column_type", "pi")
+# int sqlite3_column_int(sqlite3_stmt*, int iCol);
 sqlite3_column_int = sq3.func("i", "sqlite3_column_int", "pi")
-# using "d" return type gives wrong results
+# double sqlite3_column_double(sqlite3_stmt*, int iCol);
 sqlite3_column_double = sq3.func("d", "sqlite3_column_double", "pi")
+# const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
 sqlite3_column_text = sq3.func("s", "sqlite3_column_text", "pi")
 # sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
-# TODO: should return long int
-sqlite3_last_insert_rowid = sq3.func("i", "sqlite3_last_insert_rowid", "p")
+sqlite3_last_insert_rowid = sq3.func("l", "sqlite3_last_insert_rowid", "p")
 # const char *sqlite3_errmsg(sqlite3*);
 sqlite3_errmsg = sq3.func("s", "sqlite3_errmsg", "p")
 
-# Too recent
-##const char *sqlite3_errstr(int);
-# sqlite3_errstr = sq3.func("s", "sqlite3_errstr", "i")
-
 
 SQLITE_OK = 0
 SQLITE_ERROR = 1
@@ -78,8 +79,10 @@ class Connections:
         return Cursor(self.h)
 
     def close(self):
-        s = sqlite3_close(self.h)
-        check_error(self.h, s)
+        if self.h:
+            s = sqlite3_close(self.h)
+            check_error(self.h, s)
+            self.h = None
 
 
 class Cursor:
@@ -96,7 +99,6 @@ class Cursor:
         if params:
             params = [quote(v) for v in params]
             sql = sql % tuple(params)
-        print(sql)
 
         stmnt_ptr = bytes(get_ptr_size())
         res = sqlite3_prepare(self.h, sql, -1, stmnt_ptr, None)
@@ -104,22 +106,23 @@ class Cursor:
         self.stmnt = int.from_bytes(stmnt_ptr, sys.byteorder)
         self.num_cols = sqlite3_column_count(self.stmnt)
 
-        # If it's not select, actually execute it here
-        # num_cols == 0 for statements which don't return data (=> modify it)
         if not self.num_cols:
             v = self.fetchone()
+            # If it's not select, actually execute it here
+            # num_cols == 0 for statements which don't return data (=> modify it)
             assert v is None
             self.lastrowid = sqlite3_last_insert_rowid(self.h)
 
     def close(self):
-        s = sqlite3_finalize(self.stmnt)
-        check_error(self.h, s)
+        if self.stmnt:
+            s = sqlite3_finalize(self.stmnt)
+            check_error(self.h, s)
+            self.stmnt = None
 
     def make_row(self):
         res = []
         for i in range(self.num_cols):
             t = sqlite3_column_type(self.stmnt, i)
-            # print("type", t)
             if t == SQLITE_INTEGER:
                 res.append(sqlite3_column_int(self.stmnt, i))
             elif t == SQLITE_FLOAT:
@@ -132,7 +135,6 @@ class Cursor:
 
     def fetchone(self):
         res = sqlite3_step(self.stmnt)
-        # print("step:", res)
         if res == SQLITE_DONE:
             return None
         if res == SQLITE_ROW:

unix-ffi/sqlite3/test_sqlite3.py

@@ -17,3 +17,6 @@ while True:
     assert row == e
 
 assert expected == []
+
+cur.close()
+conn.close()

unix-ffi/sqlite3/test_sqlite3_2.py

@@ -10,3 +10,6 @@ assert cur.lastrowid == 1
 cur.execute("SELECT * FROM foo")
 assert cur.fetchone() == (42,)
 assert cur.fetchone() is None
+
+cur.close()
+conn.close()