update lex tool to find paths on windows

3 files changed, 57 insertions, 10 deletions

diff --git a/src/CHANGES.txt b/src/CHANGES.txt
index 0d02ec0..bfea661 100755
--- a/src/CHANGES.txt
+++ b/src/CHANGES.txt
@@ -19,6 +19,9 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
     - Change the default for AppendENVPath to delete_existing=0, so path
       order will not be changed, unless explicitly set (Issue #3276)
     - Fixed bug which threw error when running SCons on windows system with no MSVC installed.
+    - Update link tool to convert target to node before accessing node member
+    - Update mingw tool to remove MSVC like nologo CCFLAG
+    - Update lex tool to work in mingw environments
 
   From Mats Wichmann:
     - Quiet open file ResourceWarnings on Python >= 3.6 caused by
@@ -42,8 +45,6 @@ RELEASE 3.0.4 - Mon, 20 Jan 2019 22:49:27 +0000
       Issues #3268 & Issue #3222
     - Initial support for ARM targets with Visual Studio 2017 - Issue #3182 (You must set TARGET_ARCH for this to work)
     - Update TempFileMunge class to use PRINT_CMD_LINE_FUNC
-    - Update link tool to convert target to node before accessing node member
-    - Update mingw tool to remove MSVC like nologo CCFLAG
 
   From Tobias Herzog
     - Enhance cpp scanner regex logic to detect if/elif expressions without whitespaces but
diff --git a/src/engine/SCons/Tool/lex.py b/src/engine/SCons/Tool/lex.py
index 280c768..732c0da 100644
--- a/src/engine/SCons/Tool/lex.py
+++ b/src/engine/SCons/Tool/lex.py
@@ -34,10 +34,13 @@ selection method.
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import os.path
+import sys
 
 import SCons.Action
 import SCons.Tool
 import SCons.Util
+from SCons.Platform.mingw import MINGW_DEFAULT_PATHS
+from SCons.Platform.cygwin import CYGWIN_DEFAULT_PATHS
 
 LexAction = SCons.Action.Action("$LEXCOM", "$LEXCOMSTR")
 
@@ -64,10 +67,42 @@ def lexEmitter(target, source, env):
                 target.append(fileName)
     return (target, source)
 
+def get_lex_path(env, append_paths=False):
+    """
+    Find the a path containing the lex or flex binaries. If a construction 
+    environment is passed in then append the path to the ENV PATH.
+    """
+    # save existing path to reset if we don't want to append any paths
+    envPath = env['ENV']['PATH']
+    
+    lex = SCons.Tool.find_program_path(env, 'lex', default_paths=MINGW_DEFAULT_PATHS + CYGWIN_DEFAULT_PATHS )
+    if lex:
+        if not append_paths:
+            env['ENV']['PATH'] = envPath
+        else:
+            lex_bin_dir = os.path.dirname(lex)
+            env.AppendENVPath('PATH', lex_bin_dir)
+        return lex
+
+    flex = SCons.Tool.find_program_path(env, 'flex', default_paths=MINGW_DEFAULT_PATHS + CYGWIN_DEFAULT_PATHS )
+    if flex:
+        if not append_paths:
+            env['ENV']['PATH'] = envPath
+        else:
+            flex_bin_dir = os.path.dirname(flex)
+            env.AppendENVPath('PATH', flex_bin_dir)
+        return flex
+    else:
+        SCons.Warnings.Warning('lex tool requested, but lex or flex binary not found in ENV PATH')
+
+
 def generate(env):
     """Add Builders and construction variables for lex to an Environment."""
     c_file, cxx_file = SCons.Tool.createCFileBuilders(env)
 
+    if sys.platform == 'win32':
+        get_lex_path(env, append_paths=True)
+
     # C
     c_file.add_action(".l", LexAction)
     c_file.add_emitter(".l", lexEmitter)
@@ -82,13 +117,16 @@ def generate(env):
     # C++
     cxx_file.add_action(".ll", LexAction)
     cxx_file.add_emitter(".ll", lexEmitter)
-
-    env["LEX"]      = env.Detect("flex") or "lex"
+    
+    env["LEX"] = env.Detect("flex") or "lex"
     env["LEXFLAGS"] = SCons.Util.CLVar("")
     env["LEXCOM"] = "$LEX $LEXFLAGS -t $SOURCES > $TARGET"
 
 def exists(env):
-    return env.Detect(["flex", "lex"])
+    if sys.platform == 'win32':
+        return get_lex_path(env)
+    else:
+        return env.Detect(["flex", "lex"])
 
 # Local Variables:
 # tab-width:4
diff --git a/test/LEX/live.py b/test/LEX/live.py
index 3d697d5..853e97c 100644
--- a/test/LEX/live.py
+++ b/test/LEX/live.py
@@ -28,6 +28,8 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 Test LEX and LEXFLAGS with a live lex.
 """
 
+import sys
+
 import TestSCons
 
 _exe = TestSCons._exe
@@ -40,15 +42,24 @@ lex = test.where_is('lex') or test.where_is('flex')
 if not lex:
     test.skip_test('No lex or flex found; skipping test.\n')
 
+tools = "'default'"
+if sys.platform == 'win32':
+    # make sure mingw is installed on win32
+    if not test.where_is('gcc'):
+        test.skip_test('No mingw on windows; skipping test.\n')
+    # lex on win32 has a dependencies on mingw for unix headers
+    # so add it as a tool to the environment.
+    tools += ", 'mingw'"
 
 
 test.file_fixture('wrapper.py')
 
 test.write('SConstruct', """
-foo = Environment()
+foo = Environment(tools=[%(tools)s])
 lex = foo.Dictionary('LEX')
 bar = Environment(LEX = r'%(_python_)s wrapper.py ' + lex,
-                  LEXFLAGS = '-b')
+                  LEXFLAGS = '-b',
+                  tools=[%(tools)s])
 foo.Program(target = 'foo', source = 'foo.l')
 bar.Program(target = 'bar', source = 'bar.l')
 """ % locals())
@@ -82,9 +93,6 @@ test.must_not_exist(test.workpath('lex.backup'))
 
 test.run(program = test.workpath('foo'), stdin = "a\n", stdout = "Afoo.lA\n")
 
-
-
-
 test.run(arguments = 'bar' + _exe)
 
 test.must_match(test.workpath('wrapper.out'), "wrapper.py\n")