Consolidate the exec/eval bits, switch anonfunc to better_exec, etc

The methodpool, ${@} expansions, anonymous python functions, event handlers
now all run with the same global context, ensuring a consistent environment
for them.  Added a bb.utils.better_eval function which does an eval() with the
same globals as better_exec.

(Bitbake rev: 424d7e267b009cc19b8503eadab782736d9597d0)

Signed-off-by: Chris Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

bitbake/lib/bb/utils.py

@@ -21,9 +21,16 @@ BitBake Utility Functions
 
 separators = ".-"
 
-import re, fcntl, os, types, bb, string, stat, shutil
+import re, fcntl, os, types, bb, string, stat, shutil, time
 from commands import getstatusoutput
 
+# Context used in better_exec, eval
+_context = {
+    "os": os,
+    "bb": bb,
+    "time": time,
+}
+
 def explode_version(s):
     r = []
     alpha_regexp = re.compile('^([a-zA-Z]+)(.*)$')
@@ -164,13 +171,13 @@ def _print_trace(body, line):
         bb.msg.error(bb.msg.domain.Util, "\t%.4d:%s" % (i, body[i-1]) )
 
 
-def better_compile(text, file, realfile):
+def better_compile(text, file, realfile, mode = "exec"):
     """
     A better compile method. This method
     will print  the offending lines.
     """
     try:
-        return compile(text, file, "exec")
+        return compile(text, file, mode)
     except Exception, e:
         import bb,sys
 
@@ -193,7 +200,7 @@ def better_exec(code, context, text, realfile):
     """
     import bb,sys
     try:
-        exec code in context
+        exec code in _context, context
     except:
         (t,value,tb) = sys.exc_info()
 
@@ -215,6 +222,9 @@ def better_exec(code, context, text, realfile):
         
         raise
 
+def better_eval(source, locals):
+    return eval(source, _context, locals)
+
 def Enum(*names):
    """
    A simple class to give Enum support