Reimplement profile as a callable class.

Add more tests.

rasterio/__init__.py

@@ -12,6 +12,7 @@
     bool_, ubyte, uint8, uint16, int16, uint32, int32, float32, float64,
     complex_)
 from rasterio.five import string_types
+from rasterio.profiles import default_gtiff_profile
 from rasterio.transform import Affine, guard_transform
 
 # These modules are imported from the Cython extensions, but are also import
@@ -165,18 +166,3 @@ def pad(array, transform, pad_width, mode=None, **kwargs):
     padded_trans[2] -= pad_width*padded_trans[0]
     padded_trans[5] -= pad_width*padded_trans[4]
     return padded_array, Affine(*padded_trans[:6])
-
-
-def default_gtiff_profile(**kwds):
-    """Return a mapping suitable for writing new GeoTIFF datasets."""
-    profile = {
-        'driver': 'GTiff',
-        'interleave': 'band',
-        'tiled': True,
-        'blockxsize': 256,
-        'blockysize': 256,
-        'compress': 'lzw',
-        'nodata': 0,
-        'dtype': uint8 }
-    profile.update(**kwds)
-    return profile

rasterio/profiles.py

@@ -0,0 +1,40 @@
+"""Raster dataset profiles."""
+
+from rasterio.dtypes import uint8
+
+
+class Profile:
+    """Base class for Rasterio dataset profiles.
+
+    Subclasses will declare a format driver and driver-specific
+    creation options.
+    """
+    driver = None
+    defaults = {}
+
+    def __call__(self, **kwargs):
+        """Return a mapping suitable for writing new GeoTIFF datasets."""
+        if kwargs.get('driver', self.driver) != self.driver:
+            raise ValueError(
+                "Overriding this profile's driver is not allowed.")
+        profile = self.defaults.copy()
+        profile.update(**kwargs)
+        profile['driver'] = self.driver
+        return profile
+
+
+class DefaultGTiffProfile(Profile):
+    """A tiled, band-interleaved, LZW-compressed, 8-bit GTiff profile."""
+    driver = 'GTiff'
+    defaults = {
+        'interleave': 'band',
+        'tiled': True,
+        'blockxsize': 256,
+        'blockysize': 256,
+        'compress': 'lzw',
+        'nodata': 0,
+        'dtype': uint8
+    }
+
+
+default_gtiff_profile = DefaultGTiffProfile()

tests/test_profile.py

@@ -1,48 +1,79 @@
+import pytest
+
 import rasterio
+from rasterio.profiles import Profile, DefaultGTiffProfile
+from rasterio.profiles import default_gtiff_profile
+
+
+def test_base_profile():
+    assert Profile()()['driver'] is None
+
+
+def test_base_profile_kwarg():
+    assert Profile()(foo='bar')['foo'] == 'bar'
+
 
+def test_gtiff_profile_format():
+    assert DefaultGTiffProfile()()['driver'] == 'GTiff'
 
-def test_profile_format():
-    assert rasterio.default_gtiff_profile()['driver'] == 'GTiff'
 
+def test_gtiff_profile_interleave():
+    assert DefaultGTiffProfile()()['interleave'] == 'band'
 
-def test_profile_interleave():
-    assert rasterio.default_gtiff_profile()['interleave'] == 'band'
 
+def test_gtiff_profile_tiled():
+    assert DefaultGTiffProfile()()['tiled'] == True
 
-def test_profile_tiled():
-    assert rasterio.default_gtiff_profile()['tiled'] == True
 
+def test_gtiff_profile_blockxsize():
+    assert DefaultGTiffProfile()()['blockxsize'] == 256
 
-def test_profile_blockxsize():
-    assert rasterio.default_gtiff_profile()['blockxsize'] == 256
 
+def test_gtiff_profile_blockysize():
+    assert DefaultGTiffProfile()()['blockysize'] == 256
 
-def test_profile_blockysize():
-    assert rasterio.default_gtiff_profile()['blockysize'] == 256
 
+def test_gtiff_profile_compress():
+    assert DefaultGTiffProfile()()['compress'] == 'lzw'
 
-def test_profile_compress():
-    assert rasterio.default_gtiff_profile()['compress'] == 'lzw'
 
+def test_gtiff_profile_nodata():
+    assert DefaultGTiffProfile()()['nodata'] == 0
 
-def test_profile_nodata():
-    assert rasterio.default_gtiff_profile()['nodata'] == 0
 
+def test_gtiff_profile_dtype():
+    assert DefaultGTiffProfile()()['dtype'] == rasterio.uint8
 
-def test_profile_dtype():
-    assert rasterio.default_gtiff_profile()['dtype'] == rasterio.uint8
 
+def test_gtiff_profile_other():
+    assert DefaultGTiffProfile()(count=3)['count'] == 3
 
-def test_profile_other():
-    assert rasterio.default_gtiff_profile(count=3)['count'] == 3
+
+def test_gtiff_profile_dtype_override():
+    assert DefaultGTiffProfile()(dtype='uint16')['dtype'] == rasterio.uint16
+
+
+def test_gtiff_profile_protected_driver():
+    """Overriding the driver is not allowed."""
+    with pytest.raises(ValueError):
+        DefaultGTiffProfile()(driver='PNG')
 
 
 def test_open_with_profile(tmpdir):
         tiffname = str(tmpdir.join('foo.tif'))
         with rasterio.open(
                 tiffname,
                 'w',
-                **rasterio.default_gtiff_profile(
+                **default_gtiff_profile(
                     count=1, width=1, height=1)) as dst:
             data = dst.read()
             assert data.flatten().tolist() == [0]
+
+
+def test_profile_overlay():
+    with rasterio.open('tests/data/RGB.byte.tif') as src:
+        kwds = src.meta
+    kwds.update(**default_gtiff_profile())
+    assert kwds['tiled']
+    assert kwds['compress'] == 'lzw'
+    assert kwds['count'] == 3