[PATCH] [python] Add gdb.value_history_count()

[Matt McCormick]

An example use cause is trying to log related data with a pretty-printer.  For
example, save a file with the same name as the current history number.

This patch revision contains fixes suggested by Phil Muldoon.  And actually
strip the 'gdb/' path prefix in the ChangeLog this time.

gdb/ChangeLog

2009-30-12  Matt McCormick  <matt@mmmccormick.com>

        * value.c (get_value_history_count): New function.
        * value.h: Likewise.
        * python/py-value.c (gdbpy_value_history_count): New function.
        * python/python.c (GdbMethods): Register in module methods.
        * python/python-internal.h: Python extension definition.

gdb/doc/ChangeLog

2009-30-12  Matt McCormick  <matt@mmmccormick.com>

        * doc/gdb.texinfo (Basic Python): Document gdb.value_history_count.

gdb/testsuite/ChangeLog

2009-30-12  Matt McCormick  <matt@mmmccormick.com>

        * testsuite/gdb.python/py-value.exp (test_value_history_count): Test
	gdb.value_history_count.
---
 gdb/doc/gdb.texinfo                   |    6 ++++++
 gdb/python/py-value.c                 |    7 +++++++
 gdb/python/python-internal.h          |    1 +
 gdb/python/python.c                   |    5 +++++
 gdb/testsuite/gdb.python/py-value.exp |   17 +++++++++++++++++
 gdb/value.c                           |    6 ++++++
 gdb/value.h                           |    4 ++++
 7 files changed, 46 insertions(+), 0 deletions(-)

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 18ffb09..fe08630 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -18932,6 +18932,12 @@ If no exception is raised, the return value is always an instance of
 @code{gdb.Value} (@pxref{Values From Inferior}).
 @end defun
 
+@findex gdb.value_history_count
+@defun value_history_count
+Return an int corresponding to the number of entries in the value history
+(@pxref{Value History}).
+@end defun
+
 @findex gdb.parse_and_eval
 @defun parse_and_eval expression
 Parse @var{expression} as an expression in the current language,
diff --git a/gdb/python/py-value.c b/gdb/python/py-value.c
index 14efd79..1d185e7 100644
--- a/gdb/python/py-value.c
+++ b/gdb/python/py-value.c
@@ -403,6 +403,13 @@ valpy_get_is_optimized_out (PyObject *self, void *closure)
   Py_RETURN_FALSE;
 }
 
+/* Implementation of gdb.value_history_count.  */
+PyObject *
+gdbpy_value_history_count (PyObject *self, PyObject *args)
+{
+  return PyInt_FromLong ((long) get_value_history_count());
+}
+
 enum valpy_opcode
 {
   VALPY_ADD,
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index 47662d9..8056ba8 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -93,6 +93,7 @@ PyObject *gdbpy_lookup_symbol (PyObject *self, PyObject *args, PyObject *kw);
 PyObject *gdbpy_selected_frame (PyObject *self, PyObject *args);
 PyObject *gdbpy_block_for_pc (PyObject *self, PyObject *args);
 PyObject *gdbpy_lookup_type (PyObject *self, PyObject *args, PyObject *kw);
+PyObject *gdbpy_value_history_count (PyObject *self, PyObject* args);
 PyObject *gdbpy_inferiors (PyObject *unused, PyObject *unused2);
 PyObject *gdbpy_selected_thread (PyObject *self, PyObject *args);
 
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 707b700..debf189 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -1007,6 +1007,11 @@ Return a string explaining unwind stop reason." },
     "lookup_type (name [, block]) -> type\n\
 Return a Type corresponding to the given name." },
 
+  { "value_history_count", (PyCFunction) gdbpy_value_history_count,
+    METH_VARARGS,
+    "value_history_count () -> int.\n\
+Return an int corresponding to the number of entries in the value history." },
+
   { "lookup_symbol", (PyCFunction) gdbpy_lookup_symbol,
     METH_VARARGS | METH_KEYWORDS,
     "lookup_symbol (name [, block] [, domain]) -> (symbol, is_field_of_this)\n\
diff --git a/gdb/testsuite/gdb.python/py-value.exp b/gdb/testsuite/gdb.python/py-value.exp
index b9f2c3c..2fd7ddd 100644
--- a/gdb/testsuite/gdb.python/py-value.exp
+++ b/gdb/testsuite/gdb.python/py-value.exp
@@ -265,6 +265,22 @@ proc test_objfiles {} {
       "pretty_printers attribute must be a list.*Error while executing Python code."
 }
 
+# Test the python interface to the value history count.
+proc test_value_history_count {} {
+  global srcdir subdir binfile
+
+  # Start with a fresh gdb so we have a fresh value history count..
+  gdb_exit
+  gdb_start
+  gdb_reinitialize_dir $srcdir/$subdir
+  gdb_load ${binfile}
+ 
+  gdb_test "print 1" " = 1"
+  gdb_test "print 2" " = 2"
+  gdb_test "print 3" " = 3"
+  gdb_test "python print gdb.value_history_count()" "3"
+}
+
 proc test_value_after_death {} {
   # Construct a type while the inferior is still running.
   gdb_py_test_silent_cmd "python ptrtype = gdb.lookup_type('PTR')" \
@@ -397,6 +413,7 @@ test_value_numeric_ops
 test_value_boolean
 test_value_compare
 test_objfiles
+test_value_history_count
 
 # The following tests require execution.
 
diff --git a/gdb/value.c b/gdb/value.c
index 2f31185..1e906ff 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -343,6 +343,12 @@ allocate_computed_value (struct type *type,
 
 /* Accessor methods.  */
 
+int
+get_value_history_count ()
+{
+  return value_history_count;
+}
+
 struct value *
 value_next (struct value *value)
 {
diff --git a/gdb/value.h b/gdb/value.h
index 0da7031..8d51821 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -48,6 +48,10 @@ struct value;
 
 struct value *value_next (struct value *);
 
+/* This returns the number of entries in the value history.  */
+
+int get_value_history_count();
+
 /* Type of the value.  */
 
 extern struct type *value_type (struct value *);
-- 
1.6.6