mandoline filesystem: Rewrite using base::File.

components/filesystem/public/interfaces/file.mojom

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // TODO(vtl): notes to self:
 //  - file offsets, file positions, and file sizes are int64 (though positions
 //    and sizes must always be non-negative)
 //  - buffer size parameters (for read/write) are uint32
 
 module filesystem;
@@ skipping 15 matching lines @@
   // modifies the file position. Or maybe there should be a flag?
   Read(uint32 num_bytes_to_read, int64 offset, Whence whence)
       => (Error error, array<uint8>? bytes_read);
 
   // Writes |bytes_to_write| to the location specified by |offset|/|whence|.
   // TODO(vtl): Clarify behavior when |num_bytes_written| is less than the size
   // of |bytes_to_write|.
   Write(array<uint8> bytes_to_write, int64 offset, Whence whence)
       => (Error error, uint32 num_bytes_written);
 
-  // TODO(vtl): We definitely want 64 bits for |num_bytes_to_read|; but do we
-  // want it to be signed (this is consistent with |size| values, but
-  // inconsistent with 32-bit |num_bytes_to_read| values)? Do we want to have
-  // separate "read to end" versus "tail" (i.e., keep on reading as more data is
-  // appended) modes, and how would those be signalled?
-  ReadToStream(handle<data_pipe_producer> source,
-               int64 offset,
-               Whence whence,
-               int64 num_bytes_to_read) => (Error error);
-  WriteFromStream(handle<data_pipe_consumer> sink, int64 offset, Whence whence)
-      => (Error error);
+  // TODO(erg): Add stream variants of Read()/Write().
 
   // Gets the current file position. On success, |position| is the current
   // offset (in bytes) from the beginning of the file).
   Tell() => (Error error, int64 position);
 
   // Sets the current file position to that specified by |offset|/|whence|. On
   // success, |position| is the offset (in bytes) from the beginning of the
   // file.
   Seek(int64 offset, Whence whence) => (Error error, int64 position);
 
   // Gets information about this file. On success, |file_information| is
   // non-null and will contain this information.
   Stat() => (Error error, FileInformation? file_information);
 
   // Truncates this file to the size specified by |size| (in bytes).
   Truncate(int64 size) => (Error error);
 
   // Updates this file's atime and/or mtime to the time specified by |atime| (or
   // |mtime|, respectively), which may also indicate "now". If |atime| or
   // |mtime| is null, then the corresponding time is not modified.
   Touch(TimespecOrNow? atime, TimespecOrNow? mtime) => (Error error);
 
   // Creates a new |File| instance, which shares the same "file description".
   // I.e., the access mode, etc. (as specified to |Directory::OpenFile()| by the
   // |open_flags| argument) as well as file position.
   Dup(File& file) => (Error error);
-
-  // TODO(vtl): What are the rules for reopening (w.r.t. changing mode/flags).
-  // E.g., obviously can go from "read-write" to "read", but reverse? (probably
-  // not), can remove "append"? (probably not?). Do we allow "truncate"?
-  Reopen(File& file, uint32 open_flags) => (Error error);
-
-  // TODO(vtl): probably should have access flags (but also exec?); how do these
-  // relate to access mode?
-  AsBuffer() => (Error error, handle<shared_buffer>? buffer);
-
-  // Special-file-specific control function, for device "files". |in| and |out|
-  // are dependent on |request|.
-  // TODO(vtl): Make a master list of request values somewhere.
-  Ioctl(uint32 request, array<uint32>? in_values)
-      => (Error error, array<uint32>? out_values);
-
-  // TODO(vtl): Add a "watch"?
-  // TODO(vtl): Add something analogous to fsync(2)?
 };