[External] [stdlib] Use UnsafePointer in hex|io|os.mojo (#38796)

[External] [stdlib] Use `UnsafePointer` in `hex|io|os.mojo`

Co-authored-by: gabrieldemarmiesse <gabrieldemarmiesse@gmail.com>
Closes modularml#2403
MODULAR_ORIG_COMMIT_REV_ID: 6916ab8f901ede54c69faf09192983c3f8c58cbb

stdlib/src/builtin/hex.mojo

@@ -201,7 +201,7 @@ fn _try_write_int(
     # bytes from our final `buf_ptr` to the end of the buffer.
     var len = CAPACITY - offset
 
-    var strref = StringRef(rebind[Pointer[Int8]](buf_ptr), len)
+    var strref = StringRef(rebind[UnsafePointer[Int8]](buf_ptr), len)
 
     fmt.write_str(strref)
 

stdlib/src/builtin/io.mojo

@@ -322,9 +322,9 @@ fn _put(x: StringRef):
     @parameter
     if triple_is_nvidia_cuda():
         var tmp = 0
-        var arg_ptr = Pointer.address_of(tmp)
+        var arg_ptr = UnsafePointer.address_of(tmp)
         _ = external_call["vprintf", Int32](
-            x.data, arg_ptr.bitcast[Pointer[NoneType]]()
+            x.data, arg_ptr.bitcast[UnsafePointer[NoneType]]()
         )
     else:
         alias MAX_STR_LEN = 0x1000_0000

stdlib/src/os/os.mojo

@@ -24,7 +24,6 @@ from sys import os_is_linux, os_is_windows, triple_is_nvidia_cuda
 
 from memory import (
     DTypePointer,
-    Pointer,
 )
 from memory.unsafe_pointer import move_from_pointee
 
@@ -86,17 +85,17 @@ struct _dirent_macos:
     """Name of entry."""
 
 
-fn _strnlen(ptr: Pointer[Int8], max: Int) -> Int:
+fn _strnlen(ptr: UnsafePointer[Int8], max: Int) -> Int:
     var len = 0
-    while len < max and ptr.load(len):
+    while len < max and move_from_pointee(ptr + len):
         len += 1
     return len
 
 
 struct _DirHandle:
     """Handle to an open directory descriptor opened via opendir."""
 
-    var _handle: Pointer[NoneType]
+    var _handle: UnsafePointer[NoneType]
 
     fn __init__(inout self, path: String) raises:
         """Construct the _DirHandle using the path provided.
@@ -111,7 +110,7 @@ struct _DirHandle:
         if not isdir(path):
             raise "the directory '" + path + "' does not exist"
 
-        self._handle = external_call["opendir", Pointer[NoneType]](
+        self._handle = external_call["opendir", UnsafePointer[NoneType]](
             path._as_ptr()
         )
 
@@ -144,13 +143,13 @@ struct _DirHandle:
         var res = List[String]()
 
         while True:
-            var ep = external_call["readdir", Pointer[_dirent_linux]](
+            var ep = external_call["readdir", UnsafePointer[_dirent_linux]](
                 self._handle
             )
             if not ep:
                 break
-            var name = ep.load().name
-            var name_ptr = Pointer.address_of(name).bitcast[Int8]()
+            var name = move_from_pointee(ep).name
+            var name_ptr = UnsafePointer.address_of(name).bitcast[Int8]()
             var name_str = StringRef(
                 name_ptr, _strnlen(name_ptr, _dirent_linux.MAX_NAME_SIZE)
             )
@@ -169,13 +168,13 @@ struct _DirHandle:
         var res = List[String]()
 
         while True:
-            var ep = external_call["readdir", Pointer[_dirent_macos]](
+            var ep = external_call["readdir", UnsafePointer[_dirent_macos]](
                 self._handle
             )
             if not ep:
                 break
-            var name = ep.load().name
-            var name_ptr = Pointer.address_of(name).bitcast[Int8]()
+            var name = move_from_pointee(ep).name
+            var name_ptr = UnsafePointer.address_of(name).bitcast[Int8]()
             var name_str = StringRef(
                 name_ptr, _strnlen(name_ptr, _dirent_macos.MAX_NAME_SIZE)
             )
@@ -283,7 +282,7 @@ fn remove(path: String) raises:
     if error != 0:
         # TODO get error message, the following code prints it
         # var error_str = String("Something went wrong")
-        # _ = external_call["perror", Pointer[NoneType]](error_str._as_ptr())
+        # _ = external_call["perror", UnsafePointer[NoneType]](error_str._as_ptr())
         # _ = error_str
         raise Error("Can not remove file: " + path)