Replace Java based analyzer with Dart based analyzer when building SDK

sdk/bin/dartanalyzer.bat

 @echo off
-rem Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
-rem for details. All rights reserved. Use of this source code is governed by a
-rem BSD-style license that can be found in the LICENSE file.
+REM Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+REM for details. All rights reserved. Use of this source code is governed by a
+REM BSD-style license that can be found in the LICENSE file.
 
-set SCRIPT_DIR=%~dp0
-if %SCRIPT_DIR:~-1%==\ set SCRIPT_DIR=%SCRIPT_DIR:~0,-1%
+setlocal
+rem Handle the case where dart-sdk/bin has been symlinked to.
+set DIR_NAME_WITH_SLASH=%~dp0
+set DIR_NAME=%DIR_NAME_WITH_SLASH:~0,-1%%
+call :follow_links "%DIR_NAME%", RETURNED_BIN_DIR
+rem Get rid of surrounding quotes.
+for %%i in ("%RETURNED_BIN_DIR%") do set BIN_DIR=%%~fi
 
-for %%I in ("%SCRIPT_DIR%\..") do set "DART_ANALYZER_HOME=%%~fI"
-if %DART_ANALYZER_HOME:~-1%==\ set DART_ANALYZER_HOME=%DART_ANALYZER_HOME:~0,-1%
+rem Get absolute full name for SDK_DIR.
+for %%i in ("%BIN_DIR%\..\") do set SDK_DIR=%%~fi
 
-set FOUND_BATCH=0
-set FOUND_SDK=0
-for %%a in (%*) do (
-  if [%%a] == [--batch] set FOUND_BATCH=1
-  if [%%a] == [-b] set FOUND_BATCH=1
-  if [%%a] == [--dart-sdk]  set FOUND_SDK=1
+rem Remove trailing backslash if there is one
+IF %SDK_DIR:~-1%==\ set SDK_DIR=%SDK_DIR:~0,-1%
+
+set DARTANALYZER=%SDK_DIR%\..\pkg\analyzer\bin\analyzer.dart
+set DART=%BIN_DIR%\dart
+set SNAPSHOT=%BIN_DIR%\snapshots\dartanalyzer.dart.snapshot
+
+
+if exist "%SNAPSHOT%" (
+  "%DART%" "%SNAPSHOT%" %*
+) else (
+  "%DART%" "%DARTANALYZER%" %*
 )
 
-setlocal EnableDelayedExpansion
-set DART_SDK=""
-if [%FOUND_SDK%] == [0] (
-  if exist "%DART_ANALYZER_HOME%\lib\core\core.dart" (
-    set DART_SDK=--dart-sdk "%DART_ANALYZER_HOME%"
-  ) else (
-    for /f %%i in ('echo %DART_ANALYZER_HOME%') do set DART_SDK_HOME=%%~dpi\dart-sdk
-    if exist "!DART_SDK_HOME!" (
-      set DART_SDK=--dart-sdk !DART_SDK_HOME!
-    ) else (
-      for /f %%j in ('call echo !DART_SDK_HOME!') do set DART_SDK_HOME=%%~dpj\dart-sdk
-      if exist "!DART_SDK_HOME!" (
-        set DART_SDK=--dart-sdk !DART_SDK_HOME!
-      ) else (
-        echo Couldn't find Dart SDK. Specify with --dart-sdk cmdline argument
-      )
-    )
-  )
+endlocal
+
+exit /b %errorlevel%
+
+:follow_links
+setlocal
+for %%i in (%1) do set result=%%~fi
+set current=

[ricow1, 2014/04/23 17:36:18]

I pretty much suck at bat scripts - could you add a comment about what is
happening here

[aam-me, 2014/04/23 19:28:51]

https://chromiumcodereview.appspot.com/11740040/ has short exchange regarding
what the code below does:

This is what "dir /a:l" output looks like when you have symbolic
links(<JUNCTION>s):
===
C:\def ghi>dir /a:l 
 Volume in drive C has no label.
 Volume Serial Number is 9401-7D51

 Directory of C:\

01/03/2013  10:11 PM    <JUNCTION>     abc def
[c:\dart_bleeding\dart-repo.9\dart\build\ReleaseIA32\dart-sdk]
01/03/2013  10:56 PM    <JUNCTION>     def ghi
[c:\dart_bleeding\dart-repo.9\dart\build\ReleaseIA32\dart-sdk\bin]
===

So in the output of 'dir /a:l "targetdir"' we are looking for a filename
surrounded by right angle bracket and left square bracket. Once we get that
filename, which is name of the link, we recursively follow that.

Carets are escape characters in this context.

[danrubel, 2014/04/29 16:10:40]

Thank you! I've rolled this comment into the script.

+for /f "usebackq tokens=2 delims=[]" %%i in (`dir /a:l "%~dp1" 2^>nul ^
+                                             ^| find ">     %~n1 ["`) do (
+  set current=%%i
 )
-endlocal & set DART_SDK=%DART_SDK% & set DART_SDK_HOME=%DART_SDK_HOME%
+if not "%current%"=="" call :follow_links "%current%", result
+endlocal & set %~2=%result%
+goto :eof
 
-if exist "%DART_SDK_HOME%\util\dartanalyzer\dartanalyzer.jar" (
-  set DART_ANALYZER_LIBS=%DART_SDK_HOME%\util\dartanalyzer
-) else if exist "%DART_ANALYZER_HOME%\util\dartanalyzer\dartanalyzer.jar" (
-  set DART_ANALYZER_LIBS=%DART_ANALYZER_HOME%\util\dartanalyzer
-) else (
-  echo Configuration problem. Couldn't find dartanalyzer.jar.
-  exit /b 1
-)
-
-setlocal EnableDelayedExpansion
-set EXTRA_JVMARGS=-Xss2M 
-if [%FOUND_BATCH%] == [1] (
-  set EXTRA_JVMARGS=!EXTRA_JVMARGS! -client
-)
-endlocal & set "EXTRA_JVMARGS=%EXTRA_JVMARGS%"
-
-java %EXTRA_JVMARGS% %DART_JVMARGS% -ea -jar "%DART_ANALYZER_LIBS%\dartanalyzer.jar" %DART_SDK% %*
+:end