Write to temp file and do atomic rename in C++ DocumentAPI tests

Should avoid racing with concurrent reads by Java DocumentAPI tests.

1 files changed, 7 insertions, 3 deletions

diff --git a/documentapi/src/tests/messages/testbase.cpp b/documentapi/src/tests/messages/testbase.cpp
index 02c180853d4..ffa3bf67744 100644
--- a/documentapi/src/tests/messages/testbase.cpp
+++ b/documentapi/src/tests/messages/testbase.cpp
@@ -175,14 +175,18 @@ TestBase::dump(const mbus::Blob& blob) const
 bool
 TestBase::writeFile(const string &filename, const mbus::Blob& blob) const
 {
-    int file = open(filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0644);
+    std::string tmp_filename = filename + ".tmp";
+    int file = open(tmp_filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0644);
     if (file == -1) {
         return false;
     }
-    if (write(file, blob.data(), blob.size()) != (ssize_t)blob.size()) {
-	throw vespalib::Exception("write failed");
+    if (write(file, blob.data(), blob.size()) != static_cast<ssize_t>(blob.size())) {
+	    throw vespalib::Exception("write failed");
     }
     close(file);
+    if (rename(tmp_filename.c_str(), filename.c_str()) != 0) {
+        throw vespalib::Exception("rename failed");
+    }
     return true;
 }