fail if not recyclable

send2trash/win/IFileOperationProgressSink.py

@@ -6,6 +6,10 @@ from win32com.shell import shell, shellcon
 from win32com.server.policy import DesignatedWrapPolicy
 
 
+class E_Fail(Exception):
+    pass
+
+
 class FileOperationProgressSink(DesignatedWrapPolicy):
     _com_interfaces_ = [shell.IID_IFileOperationProgressSink]
     _public_methods_ = [
@@ -29,18 +33,30 @@ class FileOperationProgressSink(DesignatedWrapPolicy):
 
     def __init__(self):
         self._wrap_(self)
-        self.newItem = None
+        self.errors = []
 
     def PreDeleteItem(self, flags, item):
-        # Can detect cases where to stop via flags and condition below, however the operation
-        # does not actual stop, we can resort to raising an exception as that does stop things
-        # but that may need some additional considerations before implementing.
-        return 0 if flags & shellcon.TSF_DELETE_RECYCLE_IF_POSSIBLE else 0x80004005  # S_OK, or E_FAIL
+        # If TSF_DELETE_RECYCLE_IF_POSSIBLE is not set the file would not be moved to trash.
+        # Usually the code would have to return S_OK or E_FAIL to signal an abort to the file sink,
+        # however pywin32 doesn't use the return value of these callback methods [1], so we have to resort
+        # to raising an exception as that does stop things.
+        # [1] https://github.com/mhammond/pywin32/blob/1d29e4a4f317be9acbef9d5c5c5787269eacb040/com/win32com/src/PyGatewayBase.cpp#L757
+
+        name = item.GetDisplayName(shellcon.SHGDN_FORPARSING)
+        will_recycle = flags & shellcon.TSF_DELETE_RECYCLE_IF_POSSIBLE
+        if not will_recycle:
+            raise E_Fail(f"File would be deleted permanently: {name}")
+
+        return None  # HR cannot be returned here
 
     def PostDeleteItem(self, flags, item, hr_delete, newly_created):
-        if newly_created:
-            self.newItem = newly_created.GetDisplayName(shellcon.SHGDN_FORPARSING)
+        if hr_delete < 0:
+            name = item.GetDisplayName(shellcon.SHGDN_FORPARSING)
+            self.errors.append((name, hr_delete))
+
+        return None  # HR cannot be returned here
 
 
 def create_sink():
-    return pythoncom.WrapObject(FileOperationProgressSink(), shell.IID_IFileOperationProgressSink)
+    pysink = FileOperationProgressSink()
+    return pysink, pythoncom.WrapObject(pysink, shell.IID_IFileOperationProgressSink)

send2trash/win/modern.py

@@ -13,6 +13,20 @@ import pythoncom
 import pywintypes
 from win32com.shell import shell, shellcon
 from send2trash.win.IFileOperationProgressSink import create_sink
+from win32api import FormatMessage
+from winerror import ERROR_SHARING_VIOLATION
+
+winerrormap = {
+    shellcon.COPYENGINE_E_SHARING_VIOLATION_SRC: ERROR_SHARING_VIOLATION,
+}
+
+
+def win_exception(winerror, filename):
+    # see `PyErr_SetExcFromWindowsErrWithFilenameObjects`
+    msg = FormatMessage(winerror).rstrip(
+        "\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f ."
+    )
+    return WindowsError(None, msg, filename, winerror)
 
 
 def send2trash(paths):
@@ -47,7 +61,7 @@ def send2trash(paths):
     # actually try to perform the operation, this section may throw a
     # pywintypes.com_error which does not seem to create as nice of an
     # error as OSError so wrapping with try to convert
-    sink = create_sink()
+    pysink, sink = create_sink()
     try:
         for path in paths:
             item = shell.SHCreateItemFromParsingName(path, None, shell.IID_IShellItem)
@@ -55,12 +69,16 @@ def send2trash(paths):
         result = fileop.PerformOperations()
         aborted = fileop.GetAnyOperationsAborted()
         # if non-zero result or aborted throw an exception
+        assert not pysink.errors, pysink.errors
         if result or aborted:
             raise OSError(None, None, paths, result)
-    except pywintypes.com_error as error:
+    except pywintypes.com_error:
+        assert len(pysink.errors) == 1, pysink.errors
         # convert to standard OS error, allows other code to get a
         # normal errno
-        raise OSError(None, error.strerror, path, error.hresult)
+        path, hr = pysink.errors[0]
+        hr = winerrormap.get(hr + 2**32, hr)
+        raise win_exception(hr, path)
     finally:
         # Need to make sure we call this once fore every init
         pythoncom.CoUninitialize()