Add support for gdb.PYTHONDIR as $gdb_datadir/python.

Python scripts to be used by GDB can be stored in that directory,
and will be automatically found by the interpreter when importing them.
This patch also sets up <gdb_pythondir>/gdb as the directory where gdb
submodules can be stored.  For now, there is nothing there, but it can
now be added easily without further code changes.

gdb/ChangeLog:
2010-06-24  Joel Brobecker  <brobecker@adacore.com>

        * python/python.c (_initialize_python): Add new "constant"
        PYTHONDIR in gdb module.  Insert this path at the head of
        sys.path. Set gdb.__path__ to gdb.PYTHONDIR + '/gdb' and
        exec its __init__.py script if it exists in that directory.

2 files changed, 28 insertions, 0 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c94b08c..009c16a 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2010-06-24  Joel Brobecker  <brobecker@adacore.com>
+
+	* python/python.c (_initialize_python): Add new "constant"
+	PYTHONDIR in gdb module.  Insert this path at the head of
+	sys.path. Set gdb.__path__ to gdb.PYTHONDIR + '/gdb' and
+	exec its __init__.py script if it exists in that directory.
+
 2010-06-24  Kevin Buettner  <kevinb@redhat.com>
 
 	* rx-tdep.c (RX_ACC_REGNUM): Define.
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 31880c1..18b2cdc 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -668,6 +668,13 @@ Enables or disables printing of Python stack traces."),
   PyModule_AddStringConstant (gdb_module, "VERSION", (char*) version);
   PyModule_AddStringConstant (gdb_module, "HOST_CONFIG", (char*) host_name);
   PyModule_AddStringConstant (gdb_module, "TARGET_CONFIG", (char*) target_name);
+  {
+    char *gdb_pythondir;
+
+    gdb_pythondir = concat (gdb_datadir, SLASH_STRING, "python", NULL);
+    PyModule_AddStringConstant (gdb_module, "PYTHONDIR", gdb_pythondir);
+    xfree (gdb_pythondir);
+  }
 
   gdbpy_gdberror_exc = PyErr_NewException ("gdb.GdbError", NULL, NULL);
   PyModule_AddObject (gdb_module, "GdbError", gdbpy_gdberror_exc);
@@ -720,6 +727,20 @@ class GdbOutputFile:\n\
 \n\
 sys.stderr = GdbOutputFile()\n\
 sys.stdout = GdbOutputFile()\n\
+\n\
+# GDB's python scripts are stored inside gdb.PYTHONDIR.  So insert\n\
+# that directory name at the start of sys.path to allow the Python\n\
+# interpreter to find them.\n\
+sys.path.insert(0, gdb.PYTHONDIR)\n\
+\n\
+# The gdb module is implemented in C rather than in Python.  As a result,\n\
+# the associated __init.py__ script is not not executed by default when\n\
+# the gdb module gets imported.  Execute that script manually if it exists.\n\
+gdb.__path__ = [gdb.PYTHONDIR + '/gdb']\n\
+from os.path import exists\n\
+ipy = gdb.PYTHONDIR + '/gdb/__init__.py'\n\
+if exists (ipy):\n\
+  execfile (ipy)\n\
 ");
 
   /* Release the GIL while gdb runs.  */