From cfd0bd3007b291df505f8c45083453310142d681 Mon Sep 17 00:00:00 2001
From: Guilhem Charles <guilhem.charles@gmail.com>
Date: Sat, 12 Jan 2019 13:35:44 +0100
Subject: 1492 add column headers to .ninja_log

---
 src/build_log.cc      | 4 +++-
 src/build_log_test.cc | 9 +++++----
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/build_log.cc b/src/build_log.cc
index c4a08a0..774f72f 100644
--- a/src/build_log.cc
+++ b/src/build_log.cc
@@ -49,6 +49,7 @@
 namespace {
 
 const char kFileSignature[] = "# ninja log v%d\n";
+const char kFileColumnLabels[] = "# start_time end_time mtime command hash\n";
 const int kOldestSupportedVersion = 4;
 const int kCurrentVersion = 5;
 
@@ -144,7 +145,8 @@ bool BuildLog::OpenForWrite(const string& path, const BuildLogUser& user,
   fseek(log_file_, 0, SEEK_END);
 
   if (ftell(log_file_) == 0) {
-    if (fprintf(log_file_, kFileSignature, kCurrentVersion) < 0) {
+    if (fprintf(log_file_, kFileSignature, kCurrentVersion) < 0 ||
+        fprintf(log_file_, kFileColumnLabels) < 0) {
       *err = strerror(errno);
       return false;
     }
diff --git a/src/build_log_test.cc b/src/build_log_test.cc
index ad30380..eea818f 100644
--- a/src/build_log_test.cc
+++ b/src/build_log_test.cc
@@ -70,8 +70,9 @@ TEST_F(BuildLogTest, WriteRead) {
 }
 
 TEST_F(BuildLogTest, FirstWriteAddsSignature) {
-  const char kExpectedVersion[] = "# ninja log vX\n";
-  const size_t kVersionPos = strlen(kExpectedVersion) - 2;  // Points at 'X'.
+  const char kExpectedContent[] = "# ninja log vX\n"
+                                  "# start_time end_time mtime command hash\n";
+  const size_t kVersionPos = 13;  // Points at 'X'.
 
   BuildLog log;
   string contents, err;
@@ -84,7 +85,7 @@ TEST_F(BuildLogTest, FirstWriteAddsSignature) {
   ASSERT_EQ("", err);
   if (contents.size() >= kVersionPos)
     contents[kVersionPos] = 'X';
-  EXPECT_EQ(kExpectedVersion, contents);
+  EXPECT_EQ(kExpectedContent, contents);
 
   // Opening the file anew shouldn't add a second version string.
   EXPECT_TRUE(log.OpenForWrite(kTestFilename, *this, &err));
@@ -96,7 +97,7 @@ TEST_F(BuildLogTest, FirstWriteAddsSignature) {
   ASSERT_EQ("", err);
   if (contents.size() >= kVersionPos)
     contents[kVersionPos] = 'X';
-  EXPECT_EQ(kExpectedVersion, contents);
+  EXPECT_EQ(kExpectedContent, contents);
 }
 
 TEST_F(BuildLogTest, DoubleEntry) {
-- 
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