Windows: Readlink improvements (#6745)

* Windows: Use readlink emulation for File.readlink

This fixes readlink emulation for the ERROR_MORE_DATA case and general error reporting.
It now releases GVL while readlink IO operation.

The dedicated rb_readlink was introduced in commit 2ffb87995a33cdc7ba609a4b867f03f18da0c3b3
in order to improve encoding and buffer allocation.
However the encoding issues are solved since ruby-3.0 switched to UTF-8
and the buffer allocation will be improved in a later commit.

* Windows: Increase the default buffer size for reparse point info

So far nearly all queries of reparse points needed two attempts to get enough buffer.

* Windows: Remove declaration of rb_w32_wreadlink

It was removed in commit 2f6fdd3aebdee2ce04d003b206f6da78120e8235

1 files changed, 3 insertions, 5 deletions

diff --git a/win32/file.h b/win32/file.h
index 36ff27c9b1..ef701487dd 100644
--- a/win32/file.h
+++ b/win32/file.h
@@ -1,10 +1,8 @@
 #ifndef RUBY_WIN32_FILE_H
 #define RUBY_WIN32_FILE_H
 
-#define MAX_REPARSE_PATH_LEN 4092
-
 enum {
-    MINIMUM_REPARSE_BUFFER_PATH_LEN = 4
+    MINIMUM_REPARSE_BUFFER_PATH_LEN = 100
 };
 /* License: Ruby's */
 typedef struct {
@@ -18,14 +16,14 @@ typedef struct {
             USHORT PrintNameOffset;
             USHORT PrintNameLength;
             ULONG  Flags;
-            WCHAR  PathBuffer[4];
+            WCHAR  PathBuffer[MINIMUM_REPARSE_BUFFER_PATH_LEN];
         } SymbolicLinkReparseBuffer;
         struct {
             USHORT SubstituteNameOffset;
             USHORT SubstituteNameLength;
             USHORT PrintNameOffset;
             USHORT PrintNameLength;
-            WCHAR  PathBuffer[4];
+            WCHAR  PathBuffer[MINIMUM_REPARSE_BUFFER_PATH_LEN];
         } MountPointReparseBuffer;
     };
 } rb_w32_reparse_buffer_t;