Add option for exclusive creation to write

pysoundfile.py

@@ -329,12 +329,10 @@ def read(file, frames=-1, start=0, stop=None, dtype='float64', always_2d=True,
     return data, f.samplerate
 
 
-def write(data, file, samplerate,
-          subtype=None, endian=None, format=None, closefd=True):
+def write(data, file, samplerate, subtype=None, endian=None, format=None,
+          closefd=True, exclusive_creation=True):
     """Write data to a sound file.
 
-    .. note:: If `file` exists, it will be truncated and overwritten!
-
     Parameters
     ----------
     data : array_like
@@ -357,6 +355,9 @@ def write(data, file, samplerate,
 
     Other Parameters
     ----------------
+    exclusive_creation : bool
+        If ``True`` (the default), the file is opened with ``mode='x'``.
+        Otherwise, it is opened with ``mode='w'``.
     format, endian, closefd
         See :class:`SoundFile`.
 
@@ -375,7 +376,8 @@ def write(data, file, samplerate,
         channels = 1
     else:
         channels = data.shape[1]
-    with SoundFile(file, 'w', samplerate, channels,
+    mode = 'x' if exclusive_creation else 'w'
+    with SoundFile(file, mode, samplerate, channels,
                    subtype, endian, format, closefd) as f:
         f.write(data)
 

tests/test_argspec.py

@@ -30,7 +30,7 @@ def test_read_defaults():
     meth_defaults = defaults(read_method)
     init_defaults = defaults(init)
 
-    del init_defaults['mode']  # Not meaningful in read() function:
+    del init_defaults['mode']  # mode is always 'r'
 
     del func_defaults['start']
     del func_defaults['stop']
@@ -44,12 +44,13 @@ def test_read_defaults():
 
 def test_write_defaults():
     write_defaults = defaults(write_function)
+    del write_defaults['exclusive_creation']
     init_defaults = defaults(init)
 
     # Same default values as SoundFile.__init__()
     init_defaults = remove_items(init_defaults, write_defaults)
 
-    del init_defaults['mode']  # mode is always 'w'
+    del init_defaults['mode']  # mode is always 'x' or 'w'
     del init_defaults['channels']  # Inferred from data
     del init_defaults['samplerate']  # Obligatory in write()
     assert not init_defaults  # No more arguments should be left

tests/test_pysoundfile.py

@@ -194,6 +194,12 @@ def test_write_function(file_w):
     assert np.all(data == data_mono)
 
 
+def test_write_with_exclusive_creation():
+    with pytest.raises(OSError) as excinfo:
+        sf.write(data_mono, filename_mono, 44100)
+    assert "File exists" in str(excinfo.value)
+
+
 # -----------------------------------------------------------------------------
 # Test blocks() function
 # -----------------------------------------------------------------------------