For great atomicity justice!

1 files changed, 6 insertions, 1 deletions

diff --git a/backends.py b/backends.py
index a631f33..0aec6e2 100755
--- a/backends.py
+++ b/backends.py
@@ -239,7 +239,8 @@ class NinjaBackend(Backend):
 
     def generate(self):
         outfilename = os.path.join(self.environment.get_build_dir(), self.ninja_filename)
-        outfile = open(outfilename, 'w')
+        tempfilename = outfilename + '~'
+        outfile = open(tempfilename, 'w')
         self.generate_configure_files()
         outfile.write('# This is the build file for project "%s"\n' % self.build.get_project())
         outfile.write('# It is autogenerated. Do not edit by hand.\n\n')
@@ -255,6 +256,10 @@ class NinjaBackend(Backend):
             self.generate_coverage_rules(outfile)
         outfile.write('# Suffix\n\n')
         self.generate_ending(outfile)
+        # Only ovewrite the old build file after the new one has been
+        # fully created.
+        outfile.close()
+        os.replace(tempfilename, outfilename)
 
     def generate_coverage_rules(self, outfile):
         (gcovr_exe, lcov_exe, genhtml_exe) = environment.find_coverage_tools()