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tddb/td/db/binlog/BinlogReaderHelper.cpp

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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
+*/
+#include "BinlogReaderHelper.h"
+#include "BinlogReaderInterface.h"
+
+#include "td/utils/misc.h"
+
+namespace td {
+td::Status BinlogReaderHelper::parse(BinlogReaderInterface& reader, td::Slice data) {
+  SCOPE_EXIT {
+    reader.flush();
+  };
+  while (true) {
+    if (expected_prefix_size_ > 0 && expected_prefix_size_ == prefix_size_) {
+      TRY_RESULT(size, reader.parse(MutableSlice(buf_.data(), prefix_size_)));
+      if (size < 0) {
+        if (expected_prefix_size_ > td::narrow_cast<size_t>(-size)) {
+          return td::Status::Error("BinlogReader decreased logevent size estimation (1)");
+        }
+        expected_prefix_size_ = static_cast<size_t>(-size);
+      } else {
+        if (expected_prefix_size_ != td::narrow_cast<size_t>(size)) {
+          return td::Status::Error("BinlogReader changed logevent");
+        }
+        prefix_size_ = 0;
+        expected_prefix_size_ = 0;
+      }
+    }
+
+    if (data.empty()) {
+      break;
+    }
+
+    if (expected_prefix_size_ > 0) {
+      CHECK(expected_prefix_size_ < buf_.size());
+      CHECK(prefix_size_ < expected_prefix_size_);
+      auto got = data.copy().truncate(expected_prefix_size_ - prefix_size_);
+      reader.flush();
+      auto dest = td::MutableSlice(buf_.data(), buf_.size()).substr(prefix_size_);
+      if (dest.size() < got.size()) {
+        return td::Status::Error("Too big logevent");
+      }
+      dest.copy_from(got);
+      prefix_size_ += got.size();
+      data = data.substr(got.size());
+      continue;
+    }
+
+    CHECK(!data.empty());
+
+    TRY_RESULT(size, reader.parse(data));
+    if (size < 0) {
+      expected_prefix_size_ = td::narrow_cast<size_t>(-size);
+      prefix_size_ = data.size();
+      if (expected_prefix_size_ < prefix_size_) {
+        return td::Status::Error("BinlogReader waits for less data than it already has");
+      }
+      if (expected_prefix_size_ > buf_.size()) {
+        return td::Status::Error("BinlogReader waits for too big logevent");
+      }
+      reader.flush();
+      td::MutableSlice(buf_.data(), prefix_size_).copy_from(data);
+      break;
+    }
+    if (size == 0) {
+      return td::Status::Error("BinlogReader parseed nothing and asked for nothing");
+    }
+    if (td::narrow_cast<size_t>(size) > data.size()) {
+      return td::Status::Error("BinlogReader parseed more than was given");
+    }
+    data = data.substr(static_cast<size_t>(size));
+  }
+  return td::Status::OK();
+}
+
+size_t BinlogReaderHelper::unparsed_size() const {
+  return prefix_size_;
+}
+
+}  // namespace td