Let sqlite use fdatasync() on Linux-based systems

third_party/sqlite/sqlite.gyp

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     'use_system_sqlite%': 0,
     'required_sqlite_version': '3.6.1',
   },
   'target_defaults': {
@@ skipping 44 matching lines @@
         ['os_posix == 1', {
           'defines': [
             # Allow xSleep() call on Unix to use usleep() rather than sleep().
             # Microsecond precision is better than second precision.  Should
             # only affect contended databases via the busy callback.  Browser
             # profile databases are mostly exclusive, but renderer databases may
             # allow for contention.
             'HAVE_USLEEP=1',
           ],
         }],
+        ['OS == "linux" or OS == "android"', {
+          'defines': [
+            # Linux provides fdatasync(), a faster equivalent of fsync().
+            'fdatasync=fdatasync',
+          ],
+        }],

[Scott Hess - ex-Googler, 2015/03/26 17:46:00]

I couldn't figure out if this should be here...

[Scott Hess - ex-Googler, 2015/03/26 21:51:07]

I was updating my Linux client, so I patched your CL in and on the
straight-Linux client, this doesn't hit the define, and strace shows fdatasync
being called, so this works.

And since I don't know where it should be, and GN will hopefully remove the need
for this file, I guess this is fine.

[hashimoto, 2015/03/27 05:15:02]

I chose this place because this |fdatasync| is used in the same place as
SQLITE_NO_SYNC (namely, full_fsync() function in sqlite3.c).

         ['use_system_sqlite', {
           'type': 'none',
           'direct_dependent_settings': {
             'defines': [
               'USE_SYSTEM_SQLITE',
             ],
           },
 
           'conditions': [
             ['OS == "ios"', {
@@ skipping 50 matching lines @@
           'msvs_disabled_warnings': [
             4018, 4244, 4267,
           ],
           'conditions': [
             ['OS=="linux"', {
               'link_settings': {
                 'libraries': [
                   '-ldl',
                 ],
               },
             }],

[Scott Hess - ex-Googler, 2015/03/26 17:46:00]

Or here,

             ['OS == "mac" or OS == "ios"', {
               'link_settings': {
                 'libraries': [
                   '$(SDKROOT)/System/Library/Frameworks/CoreFoundation.framework',
                 ],
               },
             }],
             ['OS == "android"', {
               'defines': [
                 'SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT=1048576',
                 'SQLITE_DEFAULT_AUTOVACUUM=1',
                 'SQLITE_TEMP_STORE=3',
                 'SQLITE_ENABLE_FTS3_BACKWARDS',
                 'SQLITE_DEFAULT_FILE_FORMAT=4',

[Scott Hess - ex-Googler, 2015/03/26 17:46:00]

and here.

               ],
             }],
             ['os_posix == 1 and OS != "mac" and OS != "android"', {
               'cflags': [
                 # SQLite doesn't believe in compiler warnings,
                 # preferring testing.
                 #   http://www.sqlite.org/faq.html#q17
                 '-Wno-int-to-pointer-cast',
                 '-Wno-pointer-to-int-cast',
               ],
@@ skipping 43 matching lines @@
             '../icu/icu.gyp:icuuc',
           ],
           'sources': [
             'src/ext/icu/icu.c',
           ],
         },
       ],
     }],
   ],
 }