Add MakeTempFile function

We need a function to (semi-)properly create a temporary file.

Bug: 73487244
Test: unittests
Change-Id: I486935b4bd9e85aad2eff6fc2fd9f88d0013cf17

5 files changed, 35 insertions, 1 deletions

diff --git a/Android.bp b/Android.bp
index d95bc49..5d99dcb 100644
--- a/Android.bp
+++ b/Android.bp
@@ -98,6 +98,7 @@ cc_test {
         "src/sample_generator.cc",
         "src/stream_unittest.cc",
         "src/testrunner.cc",
+        "src/unittest_common.cc",
         "src/utils_unittest.cc",
     ],
     shared_libs: [
diff --git a/puffin.gyp b/puffin.gyp
index 33f8688..4903e00 100644
--- a/puffin.gyp
+++ b/puffin.gyp
@@ -171,6 +171,7 @@
             'src/puff_io_unittest.cc',
             'src/puffin_unittest.cc',
             'src/stream_unittest.cc',
+            'src/unittest_common.cc',
             'src/utils_unittest.cc',
           ],
         },
diff --git a/src/patching_unittest.cc b/src/patching_unittest.cc
index d478262..d6327cf 100644
--- a/src/patching_unittest.cc
+++ b/src/patching_unittest.cc
@@ -30,7 +30,8 @@ void TestPatching(const Buffer& src_buf,
                   const vector<BitExtent>& dst_deflates,
                   const Buffer patch) {
   Buffer patch_out;
-  string patch_path = "/tmp/patch.tmp";
+  string patch_path;
+  ASSERT_TRUE(MakeTempFile(&patch_path, nullptr));
   ScopedPathUnlinker scoped_unlinker(patch_path);
   ASSERT_TRUE(PuffDiff(src_buf, dst_buf, src_deflates, dst_deflates, patch_path,
                        &patch_out));
diff --git a/src/unittest_common.cc b/src/unittest_common.cc
new file mode 100644
index 0000000..b542740
--- /dev/null
+++ b/src/unittest_common.cc
@@ -0,0 +1,26 @@
+// Copyright 2018 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "puffin/src/unittest_common.h"
+
+namespace puffin {
+
+using std::string;
+
+bool MakeTempFile(string* filename, int* fd) {
+  char tmp_template[] = "/tmp/puffin-XXXXXX";
+  int mkstemp_fd = mkstemp(tmp_template);
+  TEST_AND_RETURN_FALSE(mkstemp_fd >= 0);
+  if (filename) {
+    *filename = tmp_template;
+  }
+  if (fd) {
+    *fd = mkstemp_fd;
+  } else {
+    close(mkstemp_fd);
+  }
+  return true;
+}
+
+}  // namespace puffin
diff --git a/src/unittest_common.h b/src/unittest_common.h
index ac1e71c..d0bbb02 100644
--- a/src/unittest_common.h
+++ b/src/unittest_common.h
@@ -29,6 +29,11 @@ class ScopedPathUnlinker {
   DISALLOW_COPY_AND_ASSIGN(ScopedPathUnlinker);
 };
 
+// Makes a temporary file as /tmp/puffin-XXXXXX. Both |filename| and |fd| are
+// optional, but if given, they will be populated with the new temporary file's
+// values.
+bool MakeTempFile(std::string* filename, int* fd);
+
 // clang-format off
 // Uncompressed deflate block.
 const Buffer kRaw1 = {0x01, 0x02, 0x03, 0x04, 0x05};