Turn on LevelDB logging

third_party/leveldatabase/chromium_logger.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef THIRD_PARTY_LEVELDATABASE_CHROMIUM_LOGGER_H_
+#define THIRD_PARTY_LEVELDATABASE_CHROMIUM_LOGGER_H_
+
+#include <algorithm>
+#include <stdio.h>
+#include "base/string_util.h"
+#include "base/time.h"
+#include "leveldb/env.h"
+
+namespace leveldb {
+
+class ChromiumLogger : public Logger {
+ public:
+  ChromiumLogger(FILE* f) : file_(f) { }
+  virtual ~ChromiumLogger() {
+    fclose(file_);
+  }
+  virtual void Logv(const char* format, va_list ap) {
+    const long long unsigned int thread_id =
+        ::base::PlatformThread::CurrentId();
+
+    // We try twice: the first time with a fixed-size stack allocated buffer,
+    // and the second time with a much larger dynamically allocated buffer.
+    char buffer[500];
+    for (int iter = 0; iter < 2; iter++) {
+      char* base;
+      int bufsize;
+      if (iter == 0) {
+        bufsize = sizeof(buffer);
+        base = buffer;
+      } else {
+        bufsize = 30000;
+        base = new char[bufsize];
+      }
+      char* p = base;
+      char* limit = base + bufsize;
+
+      ::base::Time::Exploded t;
+      ::base::Time::Now().LocalExplode(&t);
+
+      p += ::base::snprintf(p, limit - p,
+                    "%04d/%02d/%02d-%02d:%02d:%02d.%03d %lld ",
+                    t.year,
+                    t.month,
+                    t.day_of_month,
+                    t.hour,
+                    t.minute,
+                    t.second,
+                    t.millisecond,
+                    thread_id);
+
+      // Print the message
+      if (p < limit) {
+        va_list backup_ap;
+        GG_VA_COPY(backup_ap, ap);
+        p += vsnprintf(p, limit - p, format, backup_ap);
+        va_end(backup_ap);
+      }
+
+      // Truncate to available space if necessary
+      if (p >= limit) {
+        if (iter == 0) {
+          continue;       // Try again with larger buffer
+        } else {
+          p = limit - 1;
+        }
+      }
+
+      // Add newline if necessary
+      if (p == base || p[-1] != '\n') {
+        *p++ = '\n';
+      }
+
+      assert(p <= limit);
+      fwrite(base, 1, p - base, file_);
+      fflush(file_);
+      if (base != buffer) {
+        delete[] base;
+      }
+      break;
+    }
+  }
+ private:
+  FILE* file_;
+};
+
+}  // namespace leveldb
+
+#endif  // THIRD_PARTY_LEVELDATABASE_CHROMIUM_LOGGER_H_