codegen: Use - instead of stdout for output to stdout

In command-line tools, ordinary filenames normally do not have
special-cased meanings, so commit 3ef742eb "Don't skip dbus-codegen tests
on Win32" was a command-line API break: in the unlikely event that a
user wanted to write to a file named exactly `stdout`, this would have
been an incompatible change.

There is a conventional pseudo-filename to represent standard output,
which is `-` (for example `cat -` is a no-op filter). Adding support
for this is technically also a command-line API break (in the very
unlikely event that a user wants to write to a file named exactly `-`,
they would now have to write it as `./-`), but filenames starting with
a dash often require special treatment anyway, so this probably will not
come as a surprise to anyone.

When the output filename is `-` we don't want to use `#ifdef _____` as
a header guard, so special-case it as `__STDOUT__` as before.

Signed-off-by: Simon McVittie <smcv@collabora.com>

gio/gdbus-2.0/codegen/codegen.py

@@ -57,6 +57,9 @@ def generate_namespace(namespace):
 
 
 def generate_header_guard(header_name):
+    if header_name == "-":
+        return "STDOUT"
+
     # There might be more characters that are safe to use than these, but lets
     # stay conservative.
     safe_valid_chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"

gio/gdbus-2.0/codegen/codegen_main.py

@@ -66,7 +66,7 @@ def find_prop(iface, prop):
 
 @contextmanager
 def file_or_stdout(filename):
-    if filename is None or filename == "stdout":
+    if filename is None or filename == "-":
         yield sys.stdout
     else:
         with open(filename, "w") as outfile:

gio/tests/codegen.py

@@ -353,7 +353,7 @@ class TestCodegen(unittest.TestCase):
 
     def test_empty_interface_header(self):
         """Test generating a header with an empty interface file."""
-        result = self.runCodegenWithInterface("", "--output", "stdout", "--header")
+        result = self.runCodegenWithInterface("", "--output", "-", "--header")
         self.assertEqual("", result.err)
         self.assertEqual(
             """{standard_top_comment}
@@ -376,14 +376,14 @@ G_END_DECLS
 
     def test_empty_interface_body(self):
         """Test generating a body with an empty interface file."""
-        result = self.runCodegenWithInterface("", "--output", "stdout", "--body")
+        result = self.runCodegenWithInterface("", "--output", "-", "--body")
         self.assertEqual("", result.err)
         self.assertEqual(
             """{standard_top_comment}
 
 {standard_config_h_include}
 
-#include "stdout.h"
+#include "-.h"
 
 {standard_header_includes}
 
@@ -437,7 +437,7 @@ G_END_DECLS
                     xml_file1.name,
                     xml_file2.name,
                     "--output",
-                    "stdout",
+                    "-",
                     header_or_body,
                 )
                 self.assertEqual("", result1.err)
@@ -446,7 +446,7 @@ G_END_DECLS
                     xml_file2.name,
                     xml_file1.name,
                     "--output",
-                    "stdout",
+                    "-",
                     header_or_body,
                 )
                 self.assertEqual("", result2.err)
@@ -652,7 +652,7 @@ G_END_DECLS
             self.runCodegenWithInterface(
                 "",
                 "--output",
-                "stdout",
+                "-",
                 "--body",
                 "--glib-min-required",
                 "hello mum",
@@ -663,7 +663,7 @@ G_END_DECLS
         probably a typo)."""
         with self.assertRaises(subprocess.CalledProcessError):
             self.runCodegenWithInterface(
-                "", "--output", "stdout", "--body", "--glib-min-required", "2.6"
+                "", "--output", "-", "--body", "--glib-min-required", "2.6"
             )
 
     def test_glib_min_required_major_only(self):
@@ -671,7 +671,7 @@ G_END_DECLS
         result = self.runCodegenWithInterface(
             "",
             "--output",
-            "stdout",
+            "-",
             "--header",
             "--glib-min-required",
             "3",
@@ -684,7 +684,7 @@ G_END_DECLS
     def test_glib_min_required_with_micro(self):
         """Test running with a --glib-min-required which contains a micro version."""
         result = self.runCodegenWithInterface(
-            "", "--output", "stdout", "--header", "--glib-min-required", "2.46.2"
+            "", "--output", "-", "--header", "--glib-min-required", "2.46.2"
         )
         self.assertEqual("", result.err)
         self.assertNotEqual("", result.out.strip())
@@ -694,13 +694,13 @@ G_END_DECLS
         probably a typo)."""
         with self.assertRaises(subprocess.CalledProcessError):
             self.runCodegenWithInterface(
-                "", "--output", "stdout", "--body", "--glib-max-allowed", "2.6"
+                "", "--output", "-", "--body", "--glib-max-allowed", "2.6"
             )
 
     def test_glib_max_allowed_major_only(self):
         """Test running with a --glib-max-allowed which contains only a major version."""
         result = self.runCodegenWithInterface(
-            "", "--output", "stdout", "--header", "--glib-max-allowed", "3"
+            "", "--output", "-", "--header", "--glib-max-allowed", "3"
         )
         self.assertEqual("", result.err)
         self.assertNotEqual("", result.out.strip())
@@ -708,7 +708,7 @@ G_END_DECLS
     def test_glib_max_allowed_with_micro(self):
         """Test running with a --glib-max-allowed which contains a micro version."""
         result = self.runCodegenWithInterface(
-            "", "--output", "stdout", "--header", "--glib-max-allowed", "2.46.2"
+            "", "--output", "-", "--header", "--glib-max-allowed", "2.46.2"
         )
         self.assertEqual("", result.err)
         self.assertNotEqual("", result.out.strip())
@@ -720,7 +720,7 @@ G_END_DECLS
         result = self.runCodegenWithInterface(
             "",
             "--output",
-            "stdout",
+            "-",
             "--header",
             "--glib-max-allowed",
             "2.63",
@@ -737,7 +737,7 @@ G_END_DECLS
             self.runCodegenWithInterface(
                 "",
                 "--output",
-                "stdout",
+                "-",
                 "--body",
                 "--glib-max-allowed",
                 "2.62",
@@ -780,9 +780,7 @@ G_END_DECLS
                   </interface>
                 </node>"""
             with self.assertRaises(subprocess.CalledProcessError):
-                self.runCodegenWithInterface(
-                    interface_xml, "--output", "stdout", "--body"
-                )
+                self.runCodegenWithInterface(interface_xml, "--output", "-", "--body")
         good_types = [
             "si{s{b(ybnqiuxtdh)}}{yv}{nv}{dv}",
             "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
@@ -798,7 +796,7 @@ G_END_DECLS
                   </interface>
                 </node>"""
             result = self.runCodegenWithInterface(
-                interface_xml, "--output", "stdout", "--body"
+                interface_xml, "--output", "-", "--body"
             )
             self.assertEqual("", result.err)
 
@@ -829,7 +827,7 @@ G_END_DECLS
 
         # Try without specifying --glib-min-required.
         result = self.runCodegenWithInterface(
-            interface_xml, "--output", "stdout", "--header"
+            interface_xml, "--output", "-", "--header"
         )
         self.assertEqual("", result.err)
         self.assertEqual(result.out.strip().count("GUnixFDList"), 6)
@@ -838,7 +836,7 @@ G_END_DECLS
         result = self.runCodegenWithInterface(
             interface_xml,
             "--output",
-            "stdout",
+            "-",
             "--header",
             "--glib-min-required",
             "2.32",
@@ -852,7 +850,7 @@ G_END_DECLS
         result = self.runCodegenWithInterface(
             interface_xml,
             "--output",
-            "stdout",
+            "-",
             "--header",
             "--glib-min-required",
             "2.64",
@@ -873,7 +871,7 @@ G_END_DECLS
 
         # Try without specifying --glib-min-required.
         result = self.runCodegenWithInterface(
-            interface_xml, "--output", "stdout", "--header"
+            interface_xml, "--output", "-", "--header"
         )
         self.assertEqual("", result.err)
         self.assertEqual(result.out.strip().count("GDBusCallFlags call_flags,"), 0)
@@ -883,7 +881,7 @@ G_END_DECLS
         result = self.runCodegenWithInterface(
             interface_xml,
             "--output",
-            "stdout",
+            "-",
             "--header",
             "--glib-min-required",
             "2.32",
@@ -897,7 +895,7 @@ G_END_DECLS
         result = self.runCodegenWithInterface(
             interface_xml,
             "--output",
-            "stdout",
+            "-",
             "--header",
             "--glib-min-required",
             "2.64",
@@ -918,9 +916,7 @@ G_END_DECLS
               </interface>
             </node>"""
 
-        result = self.runCodegenWithInterface(
-            interface_xml, "--output", "stdout", "--body"
-        )
+        result = self.runCodegenWithInterface(interface_xml, "--output", "-", "--body")
         stripped_out = result.out.strip()
         self.assertFalse(result.err)
         self.assertIs(stripped_out.count("g_signal_emit_by_name ("), 0)
@@ -956,9 +952,7 @@ G_END_DECLS
               </interface>
             </node>"""
 
-        result = self.runCodegenWithInterface(
-            interface_xml, "--output", "stdout", "--body"
-        )
+        result = self.runCodegenWithInterface(interface_xml, "--output", "-", "--body")
         stripped_out = result.out.strip()
         self.assertFalse(result.err)
         self.assertIs(stripped_out.count("g_signal_emit_by_name ("), 0)
@@ -993,9 +987,7 @@ G_END_DECLS
               </interface>
             </node>"""
 
-        result = self.runCodegenWithInterface(
-            interface_xml, "--output", "stdout", "--body"
-        )
+        result = self.runCodegenWithInterface(interface_xml, "--output", "-", "--body")
         stripped_out = result.out.strip()
         self.assertFalse(result.err)
         self.assertIs(stripped_out.count("g_signal_emit_by_name ("), 0)
@@ -1026,9 +1018,7 @@ G_END_DECLS
               </interface>
             </node>"""
 
-        result = self.runCodegenWithInterface(
-            interface_xml, "--output", "stdout", "--body"
-        )
+        result = self.runCodegenWithInterface(interface_xml, "--output", "-", "--body")
         stripped_out = result.out.strip()
         self.assertFalse(result.err)
         self.assertIs(stripped_out.count("g_cclosure_marshal_generic"), 0)
@@ -1058,7 +1048,7 @@ G_END_DECLS
             </node>"""
 
             result = self.runCodegenWithInterface(
-                interface_xml, "--output", "stdout", "--body"
+                interface_xml, "--output", "-", "--body"
             )
             stripped_out = result.out.strip()
             self.assertFalse(result.err)
@@ -1106,9 +1096,7 @@ G_END_DECLS
               </interface>
             </node>"""
 
-        result = self.runCodegenWithInterface(
-            interface_xml, "--output", "stdout", "--body"
-        )
+        result = self.runCodegenWithInterface(interface_xml, "--output", "-", "--body")
         stripped_out = result.out.strip()
         self.assertFalse(result.err)
         self.assertIs(stripped_out.count("g_cclosure_marshal_generic"), 0)
@@ -1144,9 +1132,7 @@ G_END_DECLS
               </interface>
             </node>"""
 
-        result = self.runCodegenWithInterface(
-            interface_xml, "--output", "stdout", "--body"
-        )
+        result = self.runCodegenWithInterface(interface_xml, "--output", "-", "--body")
         stripped_out = result.out.strip()
         self.assertFalse(result.err)
         self.assertIs(stripped_out.count("g_cclosure_marshal_generic"), 0)
@@ -1190,7 +1176,7 @@ G_END_DECLS
             </node>"""
 
             result = self.runCodegenWithInterface(
-                interface_xml, "--output", "stdout", "--body"
+                interface_xml, "--output", "-", "--body"
             )
             stripped_out = result.out.strip()
             self.assertFalse(result.err)
@@ -1228,7 +1214,7 @@ G_END_DECLS
             </node>"""
 
             result = self.runCodegenWithInterface(
-                interface_xml, "--output", "stdout", "--body"
+                interface_xml, "--output", "-", "--body"
             )
             stripped_out = result.out.strip()
             self.assertFalse(result.err)
@@ -1271,9 +1257,7 @@ G_END_DECLS
               </interface>
             </node>"""
 
-        result = self.runCodegenWithInterface(
-            interface_xml, "--output", "stdout", "--body"
-        )
+        result = self.runCodegenWithInterface(interface_xml, "--output", "-", "--body")
         stripped_out = result.out.strip()
         self.assertFalse(result.err)
         self.assertIs(stripped_out.count("g_cclosure_marshal_generic"), 0)
@@ -1331,9 +1315,7 @@ G_END_DECLS
               </interface>
             </node>"""
 
-        result = self.runCodegenWithInterface(
-            interface_xml, "--output", "stdout", "--body"
-        )
+        result = self.runCodegenWithInterface(interface_xml, "--output", "-", "--body")
         stripped_out = result.out.strip()
         self.assertFalse(result.err)
         self.assertIs(stripped_out.count("g_cclosure_marshal_generic"), 0)
@@ -1375,9 +1357,7 @@ G_END_DECLS
               </interface>
             </node>"""
 
-        result = self.runCodegenWithInterface(
-            interface_xml, "--output", "stdout", "--body"
-        )
+        result = self.runCodegenWithInterface(interface_xml, "--output", "-", "--body")
         stripped_out = result.out.strip()
         self.assertFalse(result.err)
         self.assertIs(stripped_out.count("g_cclosure_marshal_generic"), 0)