Implement serial API for Windows.

base/platform_file.h

 // Copyright (c) 2011 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.
 
 #ifndef BASE_PLATFORM_FILE_H_
 #define BASE_PLATFORM_FILE_H_
 #pragma once
 
 #include "build/build_config.h"
 #if defined(OS_WIN)
@@ skipping 14 matching lines @@
 const PlatformFile kInvalidPlatformFileValue = INVALID_HANDLE_VALUE;
 #elif defined(OS_POSIX)
 typedef int PlatformFile;
 const PlatformFile kInvalidPlatformFileValue = -1;
 #endif
 
 // PLATFORM_FILE_(OPEN|CREATE).* are mutually exclusive. You should specify
 // exactly one of the five (possibly combining with other flags) when opening
 // or creating a file.
 enum PlatformFileFlags {
-  PLATFORM_FILE_OPEN = 1,             // Opens a file, only if it exists.
-  PLATFORM_FILE_CREATE = 2,           // Creates a new file, only if it does not
-                                      // already exist.
-  PLATFORM_FILE_OPEN_ALWAYS = 4,      // May create a new file.
-  PLATFORM_FILE_CREATE_ALWAYS = 8,    // May overwrite an old file.
-  PLATFORM_FILE_OPEN_TRUNCATED = 16,  // Opens a file and truncates it, only if
-                                      // it exists.
-  PLATFORM_FILE_READ = 32,
-  PLATFORM_FILE_WRITE = 64,
-  PLATFORM_FILE_EXCLUSIVE_READ = 128,  // EXCLUSIVE is opposite of Windows SHARE
-  PLATFORM_FILE_EXCLUSIVE_WRITE = 256,
-  PLATFORM_FILE_ASYNC = 512,
-  PLATFORM_FILE_TEMPORARY = 1024,       // Used on Windows only
-  PLATFORM_FILE_HIDDEN = 2048,          // Used on Windows only
-  PLATFORM_FILE_DELETE_ON_CLOSE = 4096,
+  PLATFORM_FILE_OPEN = 1 << 0,             // Opens a file, only if it exists.
+  PLATFORM_FILE_CREATE = 1 << 1,           // Creates a new file, only if it
+                                           // does not already exist.
+  PLATFORM_FILE_OPEN_ALWAYS = 1 << 2,      // May create a new file.
+  PLATFORM_FILE_CREATE_ALWAYS = 1 << 3,    // May overwrite an old file.
+  PLATFORM_FILE_OPEN_TRUNCATED = 1 << 4,   // Opens a file and truncates it,
+                                           // only if it exists.
+  PLATFORM_FILE_READ = 1 << 5,
+  PLATFORM_FILE_WRITE = 1 << 6,
+  PLATFORM_FILE_EXCLUSIVE_READ = 1 << 7,   // EXCLUSIVE is opposite of Windows
+                                           // SHARE
+  PLATFORM_FILE_EXCLUSIVE_WRITE = 1 << 8,
+  PLATFORM_FILE_ASYNC = 1 << 9,
+  PLATFORM_FILE_TEMPORARY = 1 << 10,       // Used on Windows only
+  PLATFORM_FILE_HIDDEN = 1 << 11,          // Used on Windows only
+  PLATFORM_FILE_DELETE_ON_CLOSE = 1 << 12,
 
-  PLATFORM_FILE_WRITE_ATTRIBUTES = 8192,  // Used on Windows only
-  PLATFORM_FILE_ENUMERATE = 16384,  // May enumerate directory
+  PLATFORM_FILE_WRITE_ATTRIBUTES = 1 << 13,  // Used on Windows only
+  PLATFORM_FILE_ENUMERATE = 1 << 14,         // May enumerate directory
 
-  PLATFORM_FILE_SHARE_DELETE = 32768,  // Used on Windows only
+  PLATFORM_FILE_SHARE_DELETE = 1 << 15,      // Used on Windows only
+
+  PLATFORM_FILE_TERMINAL_DEVICE = 1 << 16,   // Serial port flags
 };
 
 // PLATFORM_FILE_ERROR_ACCESS_DENIED is returned when a call fails because of
 // a filesystem restriction. PLATFORM_FILE_ERROR_SECURITY is returned when a
 // browser policy doesn't allow the operation to be executed.
 enum PlatformFileError {
   PLATFORM_FILE_OK = 0,
   PLATFORM_FILE_ERROR_FAILED = -1,
   PLATFORM_FILE_ERROR_IN_USE = -2,
   PLATFORM_FILE_ERROR_EXISTS = -3,
@@ skipping 52 matching lines @@
 BASE_EXPORT bool ClosePlatformFile(PlatformFile file);
 
 // Reads the given number of bytes (or until EOF is reached) starting with the
 // given offset. Returns the number of bytes read, or -1 on error. Note that
 // this function makes a best effort to read all data on all platforms, so it is
 // not intended for stream oriented files but instead for cases when the normal
 // expectation is that actually |size| bytes are read unless there is an error.
 BASE_EXPORT int ReadPlatformFile(PlatformFile file, int64 offset,
                                  char* data, int size);
 
+// Same as above but without seek.
+BASE_EXPORT int ReadPlatformFileFromCurrentPos(PlatformFile file,
+                                               char* data, int size);
+
 // Reads the given number of bytes (or until EOF is reached) starting with the
 // given offset, but does not make any effort to read all data on all platforms.
 // Returns the number of bytes read, or -1 on error.
 BASE_EXPORT int ReadPlatformFileNoBestEffort(PlatformFile file, int64 offset,
                                              char* data, int size);
 
 // Writes the given buffer into the file at the given offset, overwritting any
 // data that was previously there. Returns the number of bytes written, or -1
 // on error. Note that this function makes a best effort to write all data on
 // all platforms.
 BASE_EXPORT int WritePlatformFile(PlatformFile file, int64 offset,
                                   const char* data, int size);
 
+// Save as above but without seek.
+BASE_EXPORT int WritePlatformFileFromCurrentPos(PlatformFile file,

[darin (slow to review), 2012/05/29 20:24:10]

nitty-nit: I forgot to consider how this would look for Write*.  You probably
want "read..from" and "write..to" _or_ you could go with "read..at" and
"write..at"

[miket_OOO, 2012/05/29 20:53:03]

Very interesting! I thought of it as "reading from" and "writing from" a certain
position (as in "start at this point and keep going FROM there"), but I surveyed
100% of the engineers in my office (N=Antony), and 100% of them thought that
"from" sounded awkward, too. I am outvoted so I won't argue.

+                                                const char* data, int size);
+
 // Truncates the given file to the given length. If |length| is greater than
 // the current size of the file, the file is extended with zeros. If the file
 // doesn't exist, |false| is returned.
 BASE_EXPORT bool TruncatePlatformFile(PlatformFile file, int64 length);
 
 // Flushes the buffers of the given file.
 BASE_EXPORT bool FlushPlatformFile(PlatformFile file);
 
 // Touches the given file.
 BASE_EXPORT bool TouchPlatformFile(PlatformFile file,
@@ skipping 37 matching lines @@
     return temp;
   }
 
  private:
   PlatformFile* value_;
 };
 
 }  // namespace base
 
 #endif  // BASE_PLATFORM_FILE_H_