trace: [tracetool] Minimize the amount of per-backend code

Backends now only contain the essential backend-specific code, and most of the work is moved to frontend code.

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 14 insertions, 32 deletions

diff --git a/scripts/tracetool/format/__init__.py b/scripts/tracetool/format/__init__.py
index 2bbbba7011..812570ff6f 100644
--- a/scripts/tracetool/format/__init__.py
+++ b/scripts/tracetool/format/__init__.py
@@ -20,17 +20,12 @@ All formats must generate their contents through the 'tracetool.out' routine.
 Format functions
 ----------------
 
-All the following functions are optional, and no output will be generated if
-they do not exist.
-
-======== =======================================================================
+======== ==================================================================
 Function Description
-======== =======================================================================
-begin    Called to generate the format-specific file header.
-end      Called to generate the format-specific file footer.
-nop      Called to generate the per-event contents when the event is disabled or
-         the selected backend is 'nop'.
-======== =======================================================================
+======== ==================================================================
+generate Called to generate a format-specific file.
+======== ==================================================================
+
 """
 
 __author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
@@ -79,25 +74,12 @@ def exists(name):
     return tracetool.try_import("tracetool.format." + name)[1]
 
 
-def _empty(events):
-    pass
-
-def generate_begin(name, events):
-    """Generate the header of the format-specific file."""
-    if not exists(name):
-        raise ValueError("unknown format: %s" % name)
-
-    name = name.replace("-", "_")
-    func = tracetool.try_import("tracetool.format." + name,
-                                "begin", _empty)[1]
-    func(events)
-
-def generate_end(name, events):
-    """Generate the footer of the format-specific file."""
-    if not exists(name):
-        raise ValueError("unknown format: %s" % name)
-
-    name = name.replace("-", "_")
-    func = tracetool.try_import("tracetool.format." + name,
-                                "end", _empty)[1]
-    func(events)
+def generate(events, format, backend):
+    if not exists(format):
+        raise ValueError("unknown format: %s" % format)
+    format = format.replace("-", "_")
+    func = tracetool.try_import("tracetool.format." + format,
+                                "generate")[1]
+    if func is None:
+        raise AttributeError("format has no 'generate': %s" % format)
+    func(events, backend)