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tdutils/td/utils/MemoryLog.h

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+/*
+    This file is part of TON Blockchain Library.
+
+    TON Blockchain Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    TON Blockchain Library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright 2017-2019 Telegram Systems LLP
+*/
+#pragma once
+
+#include "td/utils/common.h"
+#include "td/utils/logging.h"
+#include "td/utils/Slice.h"
+
+#include <atomic>
+#include <cstdio>
+#include <cstring>
+
+namespace td {
+
+template <int buffer_size = 32 * (1 << 10)>
+class MemoryLog : public LogInterface {
+  static constexpr size_t MAX_OUTPUT_SIZE = buffer_size / 16 < (8 << 10) ? buffer_size / 16 : (8 << 10);
+
+ public:
+  MemoryLog() {
+    std::memset(buffer_, ' ', sizeof(buffer_));
+  }
+
+  void append(CSlice new_slice, int log_level) override {
+    Slice slice = new_slice;
+    slice.truncate(MAX_OUTPUT_SIZE);
+    while (!slice.empty() && slice.back() == '\n') {
+      slice.remove_suffix(1);
+    }
+    size_t slice_size = slice.size();
+    CHECK(slice_size * 3 < buffer_size);
+    size_t pad_size = ((slice_size + 15) & ~15) - slice_size;
+    constexpr size_t magic_size = 16;
+    uint32 total_size = static_cast<uint32>(slice_size + pad_size + magic_size);
+    uint32 real_pos = pos_.fetch_add(total_size, std::memory_order_relaxed);
+    CHECK((total_size & 15) == 0);
+
+    uint32 start_pos = real_pos & (buffer_size - 1);
+    uint32 end_pos = start_pos + total_size;
+    if (likely(end_pos <= buffer_size)) {
+      std::memcpy(&buffer_[start_pos + magic_size], slice.data(), slice_size);
+      std::memcpy(&buffer_[start_pos + magic_size + slice_size], "                     ", pad_size);
+    } else {
+      size_t first = buffer_size - start_pos - magic_size;
+      size_t second = slice_size - first;
+      std::memcpy(&buffer_[start_pos + magic_size], slice.data(), first);
+      std::memcpy(&buffer_[0], slice.data() + first, second);
+      std::memcpy(&buffer_[second], "                            ", pad_size);
+    }
+
+    CHECK((start_pos & 15) == 0);
+    CHECK(start_pos <= buffer_size - magic_size);
+    buffer_[start_pos] = '\n';
+    size_t printed = std::snprintf(&buffer_[start_pos + 1], magic_size - 1, "LOG:%08x: ", real_pos);
+    CHECK(printed == magic_size - 2);
+    buffer_[start_pos + magic_size - 1] = ' ';
+
+    if (log_level == VERBOSITY_NAME(FATAL)) {
+      process_fatal_error(new_slice);
+    }
+  }
+
+  void rotate() override {
+  }
+
+  Slice get_buffer() const {
+    return Slice(buffer_, sizeof(buffer_));
+  }
+
+  size_t get_pos() const {
+    return pos_ & (buffer_size - 1);
+  }
+
+ private:
+  char buffer_[buffer_size];
+  std::atomic<uint32> pos_{0};
+};
+
+}  // namespace td