Refine the checks in InfoLogLevel test.

Summary:
InfoLogLevel test now checks the number of lines of the output log file
instead of the number of bytes in the log file.

This diff fixes the issue that the previous InfoLogLevel test in
auto_roll_logger_test passed in make check but fails when valgrind
is used.

Test Plan: run with make check and valgrind.

Reviewers: kailiu

Reviewed By: kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16407

util/auto_roll_logger_test.cc

@@ -5,12 +5,15 @@
 //
 #include <string>
 #include <cmath>
+#include <iostream>
+#include <fstream>
+#include <iterator>
+#include <algorithm>
 #include "util/testharness.h"
 #include "util/auto_roll_logger.h"
 #include "rocksdb/db.h"
 #include <sys/stat.h>
 #include <errno.h>
-#include <iostream>
 
 using namespace std;
 
@@ -240,52 +243,42 @@ TEST(AutoRollLoggerTest, CreateLoggerFromOptions) {
 
 TEST(AutoRollLoggerTest, InfoLogLevel) {
   InitTestDb();
-  // the lengths of DEBUG, INFO, WARN, ERROR, FATAL respectively
-  const int kInfoLogLevelNameLens[5] = {5, 4, 4, 5, 5};
 
   size_t log_size = 8192;
-  std::unique_ptr<AutoRollLogger> logger_guard(
-      new AutoRollLogger(Env::Default(), kTestDir, "", log_size, 0));
-  auto logger = logger_guard.get();
-
-  int message_length = kSampleMessage.length();
-  int log_length = 0;
-  int total_logname_length = 0;
-  for (int log_level = InfoLogLevel::FATAL; log_level >= InfoLogLevel::DEBUG;
-       log_level--) {
-    logger->SetInfoLogLevel((InfoLogLevel)log_level);
-    total_logname_length += kInfoLogLevelNameLens[log_level];
-    for (int log_type = InfoLogLevel::DEBUG; log_type <= InfoLogLevel::FATAL;
-         log_type++) {
-      // log messages with log level smaller than log_level will not be logged.
-      LogMessage((InfoLogLevel)log_type, logger, kSampleMessage.c_str());
+  int log_lines = 0;
+  // an extra-scope to force the AutoRollLogger to flush the log file when it
+  // becomes out of scope.
+  {
+    AutoRollLogger logger(Env::Default(), kTestDir, "", log_size, 0);
+    for (int log_level = InfoLogLevel::FATAL; log_level >= InfoLogLevel::DEBUG;
+         log_level--) {
+      logger.SetInfoLogLevel((InfoLogLevel)log_level);
+      for (int log_type = InfoLogLevel::DEBUG; log_type <= InfoLogLevel::FATAL;
+           log_type++) {
+        // log messages with log level smaller than log_level will not be
+        // logged.
+        LogMessage((InfoLogLevel)log_type, &logger, kSampleMessage.c_str());
+      }
+      log_lines += InfoLogLevel::FATAL - log_level + 1;
+    }
+    for (int log_level = InfoLogLevel::FATAL; log_level >= InfoLogLevel::DEBUG;
+         log_level--) {
+      logger.SetInfoLogLevel((InfoLogLevel)log_level);
+
+      // again, messages with level smaller than log_level will not be logged.
+      Debug(&logger, "%s", kSampleMessage.c_str());
+      Info(&logger, "%s", kSampleMessage.c_str());
+      Warn(&logger, "%s", kSampleMessage.c_str());
+      Error(&logger, "%s", kSampleMessage.c_str());
+      Fatal(&logger, "%s", kSampleMessage.c_str());
+      log_lines += InfoLogLevel::FATAL - log_level + 1;
     }
-    // 44 is the length of the message excluding the actual
-    // message and log name.
-    log_length += (message_length + 44) * (InfoLogLevel::FATAL - log_level + 1);
-    log_length += total_logname_length;
-    ASSERT_EQ(logger->GetLogFileSize(), log_length);
-  }
-
-  // rerun the test but using different log functions.
-  total_logname_length = 0;
-  for (int log_level = InfoLogLevel::FATAL; log_level >= InfoLogLevel::DEBUG;
-       log_level--) {
-    logger->SetInfoLogLevel((InfoLogLevel)log_level);
-    total_logname_length += kInfoLogLevelNameLens[log_level];
-
-    // again, messages with level smaller than log_level will not be logged.
-    Debug(logger, "%s", kSampleMessage.c_str());
-    Info(logger, "%s", kSampleMessage.c_str());
-    Warn(logger, "%s", kSampleMessage.c_str());
-    Error(logger, "%s", kSampleMessage.c_str());
-    Fatal(logger, "%s", kSampleMessage.c_str());
-    // 44 is the length of the message excluding the actual
-    // message and log name.
-    log_length += (message_length + 44) * (InfoLogLevel::FATAL - log_level + 1);
-    log_length += total_logname_length;
-    ASSERT_EQ(logger->GetLogFileSize(), log_length);
   }
+  std::ifstream inFile(AutoRollLoggerTest::kLogFile.c_str());
+  int lines = std::count(std::istreambuf_iterator<char>(inFile),
+                         std::istreambuf_iterator<char>(), '\n');
+  ASSERT_EQ(log_lines, lines);
+  inFile.close();
 }
 
 int OldLogFileCount(const string& dir) {