Make it easier to use emscripten from a build system.

- Allow the configuration to be specified directly in the EM_CONFIG
environment variable instead of in a config file.  The config file
approach has some shortcomings when using emscripten from a build
system (e.g. it uses a single global config file so it is hard to
configure emscripten in different ways from different build trees).
The presence of newlines in the EM_CONFIG string variable is used
to decide if the configuration is stored directly in the environment
variable or it is used to specify the config file (is this too much
of a hack?).

- Skip check_sanity() and check_engine() based on the presence of
the config file.  When running from a build system, it is the build
system's responsibility that everything is set up correctly.  Maybe
a new environment variable EM_SKIP_CHECKS or something like that
might be better to decide whether or not to run these checks?

- Do not assume that the SPIDERMONKEY_ENGINE environment variable
is set.

- Add EM_CACHE environment variable that can be used to control
where emscripten should store built libraries.

1 files changed, 26 insertions, 10 deletions

diff --git a/tools/shared.py b/tools/shared.py
index 532f561f..13160713 100644
--- a/tools/shared.py
+++ b/tools/shared.py
@@ -6,15 +6,22 @@ __rootpath__ = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))
 def path_from_root(*pathelems):
   return os.path.join(__rootpath__, *pathelems)
 
-# Config file
+# Emscripten configuration is done through the EM_CONFIG environment variable.
+# If the string value contained in this environment variable contains newline
+# separated definitions, then these definitions will be used to configure
+# Emscripten.  Otherwise, the string is understood to be a path to a settings
+# file that contains the required definitions.
 
 EM_CONFIG = os.environ.get('EM_CONFIG')
 if not EM_CONFIG:
   EM_CONFIG = '~/.emscripten'
-CONFIG_FILE = os.path.expanduser(EM_CONFIG)
-if not os.path.exists(CONFIG_FILE):
-  shutil.copy(path_from_root('settings.py'), CONFIG_FILE)
-  print >> sys.stderr, '''
+if '\n' in EM_CONFIG:
+  CONFIG_FILE = None
+else:
+  CONFIG_FILE = os.path.expanduser(EM_CONFIG)
+  if not os.path.exists(CONFIG_FILE):
+    shutil.copy(path_from_root('settings.py'), CONFIG_FILE)
+    print >> sys.stderr, '''
 ==============================================================================
 Welcome to Emscripten!
 
@@ -28,9 +35,9 @@ make sure LLVM_ROOT and NODE_JS are correct.
 This command will now exit. When you are done editing those paths, re-run it.
 ==============================================================================
 ''' % (EM_CONFIG, CONFIG_FILE)
-  sys.exit(0)
+    sys.exit(0)
 try:
-  exec(open(CONFIG_FILE, 'r').read())
+  exec(open(CONFIG_FILE, 'r').read() if CONFIG_FILE else EM_CONFIG)
 except Exception, e:
   print >> sys.stderr, 'Error in evaluating %s (at %s): %s' % (EM_CONFIG, CONFIG_FILE, str(e))
   sys.exit(1)
@@ -43,6 +50,8 @@ except Exception, e:
 def check_sanity(force=False):
   try:
     if not force:
+      if not CONFIG_FILE:
+        return # config stored directly in EM_CONFIG => skip sanity checks
       settings_mtime = os.stat(CONFIG_FILE).st_mtime
       sanity_file = CONFIG_FILE + '_sanity'
       try:
@@ -183,8 +192,11 @@ else:
 #if 'strict' not in str(SPIDERMONKEY_ENGINE): # XXX temporarily disable strict mode until we sort out some stuff
 #  SPIDERMONKEY_ENGINE += ['-e', "options('strict')"] # Strict mode in SpiderMonkey. With V8 we check that fallback to non-strict works too
 
-if 'gcparam' not in str(SPIDERMONKEY_ENGINE):
-  SPIDERMONKEY_ENGINE += ['-e', "gcparam('maxBytes', 1024*1024*1024);"] # Our very large files need lots of gc heap
+try:
+  if 'gcparam' not in str(SPIDERMONKEY_ENGINE):
+    SPIDERMONKEY_ENGINE += ['-e', "gcparam('maxBytes', 1024*1024*1024);"] # Our very large files need lots of gc heap
+except NameError:
+  pass
 
 WINDOWS = sys.platform.startswith ('win')
 
@@ -228,6 +240,8 @@ class TempFiles:
 def check_engine(engine):
   # TODO: we call this several times, perhaps cache the results?
   try:
+    if not CONFIG_FILE:
+      return True # config stored directly in EM_CONFIG => skip engine check
     return 'hello, world!' in run_js(path_from_root('tests', 'hello_world.js'), engine)
   except Exception, e:
     print 'Checking JS engine %s failed. Check %s. Details: %s' % (str(engine), EM_CONFIG, str(e))
@@ -810,7 +824,9 @@ set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)''' % { 'winfix': '' if not WINDOWS e
 
 # Permanent cache for dlmalloc and stdlibc++
 class Cache:
-  dirname = os.path.expanduser(os.path.join('~', '.emscripten_cache'))
+  dirname = os.environ.get('EM_CACHE')
+  if not dirname:
+    dirname = os.path.expanduser(os.path.join('~', '.emscripten_cache'))
 
   @staticmethod
   def erase():