sql_db: Avoid using inspect.stack(), use failsafe alternative.

Inspecting the full stack just to learn the file:line info for debugging
purposes is both expensive and error-prone. Write an alternative function
in tools/func.py that will just go N frames back and try to get the info.

bzr revid: p_christ@hol.gr-20101123135742-2jp75f3uxyg3a6b6

1 files changed, 21 insertions, 0 deletions

diff --git a/bin/tools/func.py b/bin/tools/func.py
index 8cedf6715fd..4150b3e688b 100644
--- a/bin/tools/func.py
+++ b/bin/tools/func.py
@@ -93,3 +93,24 @@ def synchronized(lock_attr='_lock'):
     return decorator
 
 
+
+from inspect import getsourcefile
+
+def frame_codeinfo(fframe, back=0):
+    """ Return a (filename, line) pair for a previous frame .
+        @return (filename, lineno) where lineno is either int or string==''
+    """
+    
+    try:
+        if not fframe:
+            return ("<unknown>", '')
+        for i in range(back):
+            fframe = fframe.f_back
+        try:
+            fname = getsourcefile(fframe)
+        except TypeError:
+            fname = '<builtin>'
+        lineno = fframe.f_lineno or ''
+        return (fname, lineno)
+    except Exception:
+        return ("<unknown>", '')