Return status. Handle double calls.

docs/python-api.rst

@@ -2431,7 +2431,7 @@ Spatialite helpers
 .. _init_spatialite:
 
 Initialize Spatialite
------------------------
+----------------------
 
 .. autofunction:: sqlite_utils.gis.init_spatialite
 
@@ -2439,7 +2439,7 @@ Initialize Spatialite
 .. _find_spatialite:
 
 Finding Spatialite
------------------
+------------------
 
 .. autofunction:: sqlite_utils.gis.find_spatialite
 

sqlite_utils/gis.py

@@ -30,12 +30,14 @@ def find_spatialite() -> str:
     return None
 
 
-def init_spatialite(db: Database, path: str) -> None:
+def init_spatialite(db: Database, path: str) -> bool:
     """
     The ``init_spatialite`` function will load and initalize the Spatialite extension.
     The ``path`` argument should be an absolute path to the compiled extension, which
     can be found using ``find_spatialite``.
 
+    Returns true if Spatialite was successfully initalized.
+
     .. code-block:: python
 
         from sqlite_utils.gis import find_spatialite, init_spatialite
@@ -60,8 +62,10 @@ def init_spatialite(db: Database, path: str) -> None:
     db.conn.load_extension(path)
     # Initialize SpatiaLite if not yet initialized
     if "spatial_ref_sys" in db.table_names():
-        return
-    db.execute("select InitSpatialMetadata(1)")
+        return False
+    cursor = db.execute("select InitSpatialMetadata(1)")
+    result = cursor.fetchone()
+    return result and bool(result[0])
 
 
 def add_geometry_column(
@@ -71,7 +75,7 @@ def add_geometry_column(
     srid: int = 4326,
     coord_dimension: str = "XY",
     not_null: bool = False,
-) -> None:
+) -> bool:
     """
     In Spatialite, a geometry column can only be added to an existing table.
     To do so, use ``add_geometry_column``, passing in a :ref:`table <reference_db_table>`
@@ -81,6 +85,8 @@ def add_geometry_column(
     `SRID 4326 <https://spatialreference.org/ref/epsg/wgs-84/>`__. These can be customized using
     the ``column_name`` and ``srid`` arguments.
 
+    Returns True if the column was successfully added, False if not.
+
     .. code-block:: python
 
         from sqlite_utils.gis import find_spatialite, init_spatialite, add_geometry_column
@@ -93,18 +99,24 @@ def add_geometry_column(
         add_geometry_column(db["locations"], "POINT")
 
     """
-    table.db.execute(
+    cursor = table.db.execute(
         "SELECT AddGeometryColumn(?, ?, ?, ?, ?, ?);",
         [table.name, column_name, srid, geometry_type, coord_dimension, int(not_null)],
     )
 
+    result = cursor.fetchone()
+    return result and bool(result[0])
 
-def create_spatial_index(table: Table, column_name: str = "geometry") -> None:
+
+def create_spatial_index(table: Table, column_name: str = "geometry") -> bool:
     """
     A spatial index allows for significantly faster bounding box queries.
     To create on, use ``create_spatial_index`` with a :ref:`table <reference_db_table>`
     and the name of an existing geometry column.
 
+    Returns True if the index was successfully created, False if not. Calling this
+    function if an index already exists is a no-op.
+
     .. code-block:: python
 
         from sqlite_utils.gis import add_geometry_column, create_spatial_index
@@ -122,4 +134,11 @@ def create_spatial_index(table: Table, column_name: str = "geometry") -> None:
         # CREATE VIRTUAL TABLE "idx_locations_geometry" USING rtree(pkid, xmin, xmax, ymin, ymax)
 
     """
-    table.db.execute("select CreateSpatialIndex(?, ?)", [table.name, column_name])
+    if f"idx_{table.name}_{column_name}" in table.db.table_names():
+        return False
+
+    cursor = table.db.execute(
+        "select CreateSpatialIndex(?, ?)", [table.name, column_name]
+    )
+    result = cursor.fetchone()
+    return result and bool(result[0])

tests/test_gis.py

@@ -70,6 +70,28 @@ def test_add_geometry_column():
     reason="sqlite3.Connection missing enable_load_extension",
 )
 def test_create_spatial_index():
+    db = Database(memory=True)
+    spatialite = gis.find_spatialite()
+    assert gis.init_spatialite(db, spatialite)
+
+    # create a table, add a geometry column with default values
+    db.create_table("locations", {"id": str, "properties": str})
+    assert gis.add_geometry_column(db["locations"], "Point", "geometry")
+
+    # index it
+    assert gis.create_spatial_index(db["locations"], "geometry")
+
+    assert "idx_locations_geometry" in db.table_names()
+
+
+@pytest.mark.skipif(
+    not gis.find_spatialite(), reason="Could not find SpatiaLite extension"
+)
+@pytest.mark.skipif(
+    not hasattr(sqlite3.Connection, "enable_load_extension"),
+    reason="sqlite3.Connection missing enable_load_extension",
+)
+def test_double_create_spatial_index():
     db = Database(memory=True)
     spatialite = gis.find_spatialite()
     gis.init_spatialite(db, spatialite)
@@ -78,7 +100,10 @@ def test_create_spatial_index():
     db.create_table("locations", {"id": str, "properties": str})
     gis.add_geometry_column(db["locations"], "Point", "geometry")
 
-    # index it
-    gis.create_spatial_index(db["locations"], "geometry")
+    # index it, return True
+    assert gis.create_spatial_index(db["locations"], "geometry")
 
     assert "idx_locations_geometry" in db.table_names()
+
+    # call it again, return False
+    assert not gis.create_spatial_index(db["locations"], "geometry")