travis: fix missing msbuild output on Windows

For some reason the CMake output to Python is missing, no matter how
hard I try. Use an alternative approach instead where Python executes
CMake and filters the output without relying on pipes in Bash.

Change-Id: I21b8b709c3a944fbd3b07e7fac59702735dd83a4
Reviewed-on: https://code.wireshark.org/review/32628
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Dario Lombardo <lomato@gmail.com>

1 files changed, 56 insertions, 32 deletions

diff --git a/tools/filter-msbuild.py b/tools/filter-msbuild.py
index 560ea1646c..c58541f17b 100755
--- a/tools/filter-msbuild.py
+++ b/tools/filter-msbuild.py
@@ -4,38 +4,62 @@
 # Copyright (C) 2019 Peter Wu <peter@lekensteyn.nl>
 # SPDX-License-Identifier: GPL-2.0-or-later
 
+import subprocess
 import sys
 
 
-# If an important message is present, print it with a newline.
-# Otherwise skip the newline but print the next line with a carriage return.
-# If the end of build is reached, just print the trailing messages (includes
-# elapsed time, warning/error counts, etc.).
-
-start_of_line = ''
-end_of_build = False
-for line in sys.stdin:
-    line = line.rstrip('\r\n')
-
-    if line.startswith('Build succeeded.'):
-        end_of_build = True
-    is_important = end_of_build or any([
-        ': error ' in line,
-        ': warning ' in line,
-        '-- FAILED.' in line,
-    ])
-
-    if is_important:
-        eol = '\n'
-        if start_of_line == '\r':
-            start_of_line = '\n'
-    else:
-        eol = ''
-
-    sys.stdout.write("%s%s%s" % (start_of_line, line, eol))
-    sys.stdout.flush()
-
-    if is_important:
-        start_of_line = ''
-    else:
-        start_of_line = '\r'
+def print_lines(f):
+    # If an important message is present, print it with a newline.
+    # Otherwise skip the newline but print the next line with a carriage return.
+    # If the end of build is reached, just print the trailing messages (includes
+    # elapsed time, warning/error counts, etc.).
+
+    start_of_line = ''
+    end_of_build = False
+    for line in iter(f.readline, ''):
+        line = line.rstrip('\r\n')
+
+        if line.startswith('Build succeeded.'):
+            end_of_build = True
+        is_important = end_of_build or any([
+            ': error ' in line,
+            ': warning ' in line,
+            '-- FAILED.' in line,
+        ])
+
+        if is_important:
+            eol = '\n'
+            if start_of_line == '\r':
+                start_of_line = '\n'
+        else:
+            eol = ''
+
+        sys.stdout.write("%s%s%s" % (start_of_line, line, eol))
+        sys.stdout.flush()
+
+        if is_important:
+            start_of_line = ''
+        else:
+            start_of_line = '\r'
+
+    # If the last line was not important, its LF was omitted so print it.
+    if not is_important:
+        sys.stdout.write('\n')
+
+
+command = sys.argv[1:]
+if command:
+    # Execute the given command and parse its output.
+    proc = subprocess.Popen(command,
+                            bufsize=1,
+                            stdout=subprocess.PIPE,
+                            stderr=subprocess.STDOUT,
+                            universal_newlines=True
+                            )
+    try:
+        print_lines(proc.stdout)
+    finally:
+        sys.exit(proc.wait())
+else:
+    # Assume a file read from stdin.
+    print_lines(sys.stdin)