move skip root to own function

python · zooba · Mar 9, 2023 · Feb 24, 2023 · Feb 25, 2023 · Feb 25, 2023
commit 6465d73d61660175f2c604541cab1c14cbf5fb8e
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
@@ -4419,6 +4419,40 @@ os__getvolumepathname_impl(PyObject *module, path_t *path)
    return result;
 }

+#if MS_WINDOWS_GAMES
+// The Windows Games API partition does not provide PathCchSkipRoot
+// so we need our own implementation
+static wchar_t*
+win32_games_skip_root(wchar_t* path)
+{
+    if (path[0] == L'\\') {
+        /* relative path with root e.g. \Windows */
+        if (path[1] != L'\\') {
+            return path + 1;
+        }
+
+        /* UNC drives e.g. \\server\share or \\?\UNC\server\share */
+        wchar_t *end = path + 2;
+        if (!wcsnicmp(end, L"?\\UNC\\", 6)) {
+            end += 6;
+        }
+
+        end = wcschr(end, '\\');
+        if (!end) {
+            return path + wcslen(path);
+        }
+        end = wcschr(end + 1, '\\');
+        return (!end) ? wcslen(path) : end + 1;
+    }
+    /* absolute / relative path with drive, e.g. C: or C:\ */
+    else if (isalpha(path[0]) && path[1] == L':') {
+        return (path[2] == L'\\') ? path + 3 : path + 2;
+    }
+
+    /* relative path */
+    return NULL;
+}
+#endif

 /*[clinic input]
 os._path_splitroot
@@ -4447,26 +4481,8 @@ os__path_splitroot_impl(PyObject *module, path_t *path)
    }

 #if MS_WINDOWS_GAMES
-    /* network share */
-    if (buffer[0] == L'\\' && buffer[1] == L'\\') {
-        end = buffer + 2;
-        for (int i = 0; i < 2; ++i) {
-            end = wcschr(end, '\\');
-            if (end == NULL) {
-                break;
-            }
-            end++;
-        }
-        ret = (end != NULL) ? S_OK : E_INVALIDARG;
-    }
-    /* Check for absolute drive path */
-    else if (buffer[0] && buffer[1] == L':' && buffer[2] == L'\\') {
-        end = buffer + 3;
-        ret = S_OK;
-    }
-    else {
-        ret = E_INVALIDARG;
-    }
+    end = win32_games_skip_root(buffer);
+    ret = (end != NULL) ? S_OK : E_INVALIDARG;
 #else
    Py_BEGIN_ALLOW_THREADS
    ret = PathCchSkipRoot(buffer, &end);
-Original file line number
+Diff line change
@@ -4419,6 +4419,40 @@ os__getvolumepathname_impl(PyObject *module, path_t *path)
         return result;
     }
+    #if MS_WINDOWS_GAMES
+    // The Windows Games API partition does not provide PathCchSkipRoot
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+    // so we need our own implementation
+    static wchar_t*
+    win32_games_skip_root(wchar_t* path)
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            zooba
  

      

      

      


        Feb 28, 2023


      
    

  


        
      
  
  
  
    

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      Just call it PathCchSkipRoot and match the prototype?
It'll break if Windows introduces the API, but unless there's some reasonable way to detect it, that's probably best. We'll want to use it when it's there.
    
  
  


    

        
      
  
  
    
  
  
  
    
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        Feb 28, 2023


      
    

  


        
      
  
  
  
    

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      This might also be better in fileutils.c with a conditional declaration in Include\internal\pycore_fileutils.h
    
  
  


    

        
      
  
  
    
  
  
  
    
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            maxbachmann
  

      

      

      


        Mar 1, 2023


      
    

  


        
      
  
  
  
    

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      I moved them into fileutils
    
  
  


    

        
      
  
  
    
  
  
  
    
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+    {
+        if (path[0] == L'\\') {
+            /* relative path with root e.g. \Windows */
+            if (path[1] != L'\\') {
+                return path + 1;
+            }
+            /* UNC drives e.g. \\server\share or \\?\UNC\server\share */
+            wchar_t *end = path + 2;
+            if (!wcsnicmp(end, L"?\\UNC\\", 6)) {
+                end += 6;
+            }
+            end = wcschr(end, '\\');
+            if (!end) {
+                return path + wcslen(path);
+            }
+            end = wcschr(end + 1, '\\');
+            return (!end) ? wcslen(path) : end + 1;
+        }
+        /* absolute / relative path with drive, e.g. C: or C:\ */
+        else if (isalpha(path[0]) && path[1] == L':') {
+            return (path[2] == L'\\') ? path + 3 : path + 2;
+        }
+        /* relative path */
+        return NULL;
+    }
+    #endif
     /*[clinic input]
     os._path_splitroot
@@ -4447,26 +4481,8 @@ os__path_splitroot_impl(PyObject *module, path_t *path)
         }
     #if MS_WINDOWS_GAMES
-        /* network share */
-        if (buffer[0] == L'\\' && buffer[1] == L'\\') {
-            end = buffer + 2;
-            for (int i = 0; i < 2; ++i) {
-                end = wcschr(end, '\\');
-                if (end == NULL) {
-                    break;
-                }
-                end++;
-            }
-            ret = (end != NULL) ? S_OK : E_INVALIDARG;
-        }
-        /* Check for absolute drive path */
-        else if (buffer[0] && buffer[1] == L':' && buffer[2] == L'\\') {
-            end = buffer + 3;
-            ret = S_OK;
-        }
-        else {
-            ret = E_INVALIDARG;
-        }
+        end = win32_games_skip_root(buffer);
+        ret = (end != NULL) ? S_OK : E_INVALIDARG;
     #else
         Py_BEGIN_ALLOW_THREADS
         ret = PathCchSkipRoot(buffer, &end);
-          Expand Down