[vfs] more accurate Windows short name detection (IDEA-144285)

platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemBase.java

@@ -74,8 +74,8 @@ public abstract class LocalFileSystemBase extends LocalFileSystem {
 
   @Override
   public VirtualFile findFileByIoFile(@NotNull File file) {
-    String path = file.getAbsolutePath();
-    return findFileByPath(path.replace(File.separatorChar, '/'));
+    String path = FileUtil.toSystemIndependentName(file.getAbsolutePath());
+    return findFileByPath(path);
   }
 
   @NotNull
@@ -197,13 +197,11 @@ public abstract class LocalFileSystemBase extends LocalFileSystem {
         path = path.substring(1);  // hack over new File(path).toURI().toURL().getFile()
       }
 
-      if (path.contains("~")) {
-        try {
-          path = new File(FileUtil.toSystemDependentName(path)).getCanonicalPath();
-        }
-        catch (IOException e) {
-          return null;
-        }
+      try {
+        path = FileUtil.resolveShortWindowsName(path);
+      }
+      catch (IOException e) {
+        return null;
       }
     }
 
@@ -227,8 +225,8 @@ public abstract class LocalFileSystemBase extends LocalFileSystem {
 
   @Override
   public VirtualFile refreshAndFindFileByIoFile(@NotNull File file) {
-    String path = file.getAbsolutePath();
-    return refreshAndFindFileByPath(path.replace(File.separatorChar, '/'));
+    String path = FileUtil.toSystemIndependentName(file.getAbsolutePath());
+    return refreshAndFindFileByPath(path);
   }
 
   @Override

platform/util/src/com/intellij/openapi/util/io/FileUtil.java

@@ -1016,6 +1016,7 @@ public class FileUtil extends FileUtilRt {
    *             Use {@link FileUtilRt#getExtension(String)} instead to get the unchanged extension.
    *             If you need to check whether a file has a specified extension use {@link FileUtilRt#extensionEquals(String, String)}
    */
+  @SuppressWarnings("StringToUpperCaseOrToLowerCaseWithoutLocale")
   @NotNull
   public static String getExtension(@NotNull String fileName) {
     return FileUtilRt.getExtension(fileName).toLowerCase();
@@ -1023,7 +1024,31 @@ public class FileUtil extends FileUtilRt {
 
   @NotNull
   public static String resolveShortWindowsName(@NotNull String path) throws IOException {
-    return SystemInfo.isWindows && StringUtil.containsChar(path, '~') ? new File(path).getCanonicalPath() : path;
+    return SystemInfo.isWindows && containsWindowsShortName(path) ? new File(path).getCanonicalPath() : path;
+  }
+
+  public static boolean containsWindowsShortName(@NotNull String path) {
+    if (StringUtil.containsChar(path, '~')) {
+      path = toSystemIndependentName(path);
+
+      int start = 0;
+      while (start < path.length()) {
+        int end = path.indexOf('/', start);
+        if (end < 0) end = path.length();
+
+        // "How Windows Generates 8.3 File Names from Long File Names", https://support.microsoft.com/en-us/kb/142982
+        int dot = path.lastIndexOf('.', end);
+        if (dot < start) dot = end;
+        if (dot - start > 2 && dot - start <= 8 && end - dot - 1 <= 3 &&
+            path.charAt(dot - 2) == '~' && Character.isDigit(path.charAt(dot - 1))) {
+          return true;
+        }
+
+        start = end + 1;
+      }
+    }
+
+    return false;
   }
 
   public static void collectMatchedFiles(@NotNull File root, @NotNull Pattern pattern, @NotNull List<File> outFiles) {
@@ -1672,4 +1697,8 @@ public class FileUtil extends FileUtilRt {
     FileAttributes lower = FileSystemUtil.getAttributes(path.toLowerCase(Locale.ENGLISH));
     return !(attributes.equals(upper) && attributes.equals(lower));
   }
+
+  public static boolean isWindowsShortName(@NotNull String fileName) {
+    return false;
+  }
 }

platform/util/testSrc/com/intellij/openapi/util/io/FileUtilLightTest.java

@@ -214,4 +214,21 @@ public class FileUtilLightTest {
 
     assertThat(FileUtil.sanitizeFileName("a+b+c")).isEqualTo("a_b_c");
   }
+
+  @Test
+  public void windowsShortName() {
+    assertTrue(FileUtil.containsWindowsShortName("C:\\dir~1"));
+    assertTrue(FileUtil.containsWindowsShortName("C:\\dir~1\\"));
+    assertTrue(FileUtil.containsWindowsShortName("C:\\dir~1\\file.txt"));
+    assertTrue(FileUtil.containsWindowsShortName("C:/dir/file~1"));
+    assertTrue(FileUtil.containsWindowsShortName("C:/dir/file~1.txt"));
+    assertTrue(FileUtil.containsWindowsShortName("C:/dir/file~1.1"));
+
+    assertFalse(FileUtil.containsWindowsShortName("~"));
+    assertFalse(FileUtil.containsWindowsShortName("C:\\some~dir"));
+    assertFalse(FileUtil.containsWindowsShortName("C:\\some-dir~1"));
+    assertFalse(FileUtil.containsWindowsShortName("C:/dir/file~1.extension"));
+    assertFalse(FileUtil.containsWindowsShortName("C:/dir/file.~1"));
+    assertFalse(FileUtil.containsWindowsShortName("C:/dir/file.ext~1"));
+  }
 }