Move log_namer to log_namer.{cc,h}

logger.{cc,h} is getting too big.  Also move more implementation from
the header to the .cc, and add comments.

Change-Id: Ia342bfade98c71d4d42f769571256c28e2c826d5
diff --git a/aos/events/logging/logger.h b/aos/events/logging/logger.h
index d4ed786..6c67130 100644
--- a/aos/events/logging/logger.h
+++ b/aos/events/logging/logger.h
@@ -12,6 +12,7 @@
 #include "absl/types/span.h"
 #include "aos/events/event_loop.h"
 #include "aos/events/logging/eigen_mpq.h"
+#include "aos/events/logging/log_namer.h"
 #include "aos/events/logging/logfile_utils.h"
 #include "aos/events/logging/logger_generated.h"
 #include "aos/events/logging/uuid.h"
@@ -25,261 +26,6 @@
 namespace aos {
 namespace logger {
 
-class LogNamer {
- public:
-  LogNamer(const Node *node) : node_(node) { nodes_.emplace_back(node_); }
-  virtual ~LogNamer() {}
-
-  virtual void WriteHeader(
-      aos::SizePrefixedFlatbufferDetachedBuffer<LogFileHeader> *header,
-      const Node *node) = 0;
-  virtual DetachedBufferWriter *MakeWriter(const Channel *channel) = 0;
-
-  virtual DetachedBufferWriter *MakeTimestampWriter(const Channel *channel) = 0;
-  virtual DetachedBufferWriter *MakeForwardedTimestampWriter(
-      const Channel *channel, const Node *node) = 0;
-  virtual void Rotate(
-      const Node *node,
-      aos::SizePrefixedFlatbufferDetachedBuffer<LogFileHeader> *header) = 0;
-  const std::vector<const Node *> &nodes() const { return nodes_; }
-
-  const Node *node() const { return node_; }
-
- protected:
-  void UpdateHeader(
-      aos::SizePrefixedFlatbufferDetachedBuffer<LogFileHeader> *header,
-      const UUID &uuid, int part_id);
-
-  const Node *const node_;
-  std::vector<const Node *> nodes_;
-};
-
-class LocalLogNamer : public LogNamer {
- public:
-  LocalLogNamer(std::string_view base_name, const Node *node)
-      : LogNamer(node),
-        base_name_(base_name),
-        uuid_(UUID::Random()),
-        data_writer_(OpenDataWriter()) {}
-
-  void WriteHeader(
-      aos::SizePrefixedFlatbufferDetachedBuffer<LogFileHeader> *header,
-      const Node *node) override {
-    CHECK_EQ(node, this->node());
-    UpdateHeader(header, uuid_, part_number_);
-    data_writer_->WriteSizedFlatbuffer(header->full_span());
-  }
-
-  DetachedBufferWriter *MakeWriter(const Channel *channel) override {
-    CHECK(configuration::ChannelIsSendableOnNode(channel, node()));
-    return data_writer_.get();
-  }
-
-  void Rotate(const Node *node,
-              aos::SizePrefixedFlatbufferDetachedBuffer<LogFileHeader> *header)
-      override {
-    CHECK(node == this->node());
-    ++part_number_;
-    *data_writer_ = std::move(*OpenDataWriter());
-    UpdateHeader(header, uuid_, part_number_);
-    data_writer_->WriteSizedFlatbuffer(header->full_span());
-  }
-
-  DetachedBufferWriter *MakeTimestampWriter(const Channel *channel) override {
-    CHECK(configuration::ChannelIsReadableOnNode(channel, node_))
-        << ": Message is not delivered to this node.";
-    CHECK(node_ != nullptr) << ": Can't log timestamps in a single node world";
-    CHECK(configuration::ConnectionDeliveryTimeIsLoggedOnNode(channel, node_,
-                                                              node_))
-        << ": Delivery times aren't logged for this channel on this node.";
-    return data_writer_.get();
-  }
-
-  DetachedBufferWriter *MakeForwardedTimestampWriter(
-      const Channel * /*channel*/, const Node * /*node*/) override {
-    LOG(FATAL) << "Can't log forwarded timestamps in a singe log file.";
-    return nullptr;
-  }
-
- private:
-  std::unique_ptr<DetachedBufferWriter> OpenDataWriter() {
-    return std::make_unique<DetachedBufferWriter>(
-        absl::StrCat(base_name_, ".part", part_number_, ".bfbs"));
-  }
-  const std::string base_name_;
-  const UUID uuid_;
-  size_t part_number_ = 0;
-  std::unique_ptr<DetachedBufferWriter> data_writer_;
-};
-
-// TODO(austin): Split naming files from making files so we can re-use the
-// naming code to predict the log file names for a provided base name.
-class MultiNodeLogNamer : public LogNamer {
- public:
-  MultiNodeLogNamer(std::string_view base_name,
-                    const Configuration *configuration, const Node *node)
-      : LogNamer(node),
-        base_name_(base_name),
-        configuration_(configuration),
-        uuid_(UUID::Random()),
-        data_writer_(OpenDataWriter()) {}
-
-  // Writes the header to all log files for a specific node.  This function
-  // needs to be called after all the writers are created.
-  void WriteHeader(
-      aos::SizePrefixedFlatbufferDetachedBuffer<LogFileHeader> *header,
-      const Node *node) override;
-
-  void Rotate(const Node *node,
-              aos::SizePrefixedFlatbufferDetachedBuffer<LogFileHeader> *header)
-      override;
-
-  // Makes a data logger for a specific channel.
-  DetachedBufferWriter *MakeWriter(const Channel *channel) override {
-    // See if we can read the data on this node at all.
-    const bool is_readable =
-        configuration::ChannelIsReadableOnNode(channel, this->node());
-    if (!is_readable) {
-      return nullptr;
-    }
-
-    // Then, see if we are supposed to log the data here.
-    const bool log_message =
-        configuration::ChannelMessageIsLoggedOnNode(channel, this->node());
-
-    if (!log_message) {
-      return nullptr;
-    }
-
-    // Now, sort out if this is data generated on this node, or not.  It is
-    // generated if it is sendable on this node.
-    if (configuration::ChannelIsSendableOnNode(channel, this->node())) {
-      return data_writer_.get();
-    }
-
-    // Ok, we have data that is being forwarded to us that we are supposed to
-    // log.  It needs to be logged with send timestamps, but be sorted enough
-    // to be able to be processed.
-    CHECK(data_writers_.find(channel) == data_writers_.end());
-
-    // Track that this node is being logged.
-    const Node *source_node = configuration::GetNode(
-        configuration_, channel->source_node()->string_view());
-
-    if (std::find(nodes_.begin(), nodes_.end(), source_node) == nodes_.end()) {
-      nodes_.emplace_back(source_node);
-    }
-
-    DataWriter data_writer;
-    data_writer.node = source_node;
-    data_writer.rotate = [this](const Channel *channel,
-                                DataWriter *data_writer) {
-      OpenWriter(channel, data_writer);
-    };
-    data_writer.rotate(channel, &data_writer);
-
-    return data_writers_.insert(std::make_pair(channel, std::move(data_writer)))
-        .first->second.writer.get();
-  }
-
-  DetachedBufferWriter *MakeForwardedTimestampWriter(
-      const Channel *channel, const Node *node) override {
-    // See if we can read the data on this node at all.
-    const bool is_readable =
-        configuration::ChannelIsReadableOnNode(channel, this->node());
-    CHECK(is_readable) << ": "
-                       << configuration::CleanedChannelToString(channel);
-
-    CHECK(data_writers_.find(channel) == data_writers_.end());
-
-    if (std::find(nodes_.begin(), nodes_.end(), node) == nodes_.end()) {
-      nodes_.emplace_back(node);
-    }
-
-    DataWriter data_writer;
-    data_writer.node = node;
-    data_writer.rotate = [this](const Channel *channel,
-                                DataWriter *data_writer) {
-      OpenForwardedTimestampWriter(channel, data_writer);
-    };
-    data_writer.rotate(channel, &data_writer);
-
-    return data_writers_.insert(std::make_pair(channel, std::move(data_writer)))
-        .first->second.writer.get();
-  }
-
-  // Makes a timestamp (or timestamp and data) logger for a channel and
-  // forwarding connection.
-  DetachedBufferWriter *MakeTimestampWriter(const Channel *channel) override {
-    const bool log_delivery_times =
-        (this->node() == nullptr)
-            ? false
-            : configuration::ConnectionDeliveryTimeIsLoggedOnNode(
-                  channel, this->node(), this->node());
-    if (!log_delivery_times) {
-      return nullptr;
-    }
-
-    return data_writer_.get();
-  }
-
-  const std::vector<const Node *> &nodes() const { return nodes_; }
-
- private:
-  // Files to write remote data to.  We want one per channel.  Maps the channel
-  // to the writer, Node, and part number.
-  struct DataWriter {
-    std::unique_ptr<DetachedBufferWriter> writer = nullptr;
-    const Node *node;
-    size_t part_number = 0;
-    UUID uuid = UUID::Random();
-    std::function<void(const Channel *, DataWriter *)> rotate;
-  };
-
-  void OpenForwardedTimestampWriter(const Channel *channel,
-                                    DataWriter *data_writer) {
-    std::string filename =
-        absl::StrCat(base_name_, "_timestamps", channel->name()->string_view(),
-                     "/", channel->type()->string_view(), ".part",
-                     data_writer->part_number, ".bfbs");
-
-    if (!data_writer->writer) {
-      data_writer->writer = std::make_unique<DetachedBufferWriter>(filename);
-    } else {
-      *data_writer->writer = DetachedBufferWriter(filename);
-    }
-  }
-
-  void OpenWriter(const Channel *channel, DataWriter *data_writer) {
-    const std::string filename = absl::StrCat(
-        base_name_, "_", channel->source_node()->string_view(), "_data",
-        channel->name()->string_view(), "/", channel->type()->string_view(),
-        ".part", data_writer->part_number, ".bfbs");
-    if (!data_writer->writer) {
-      data_writer->writer = std::make_unique<DetachedBufferWriter>(filename);
-    } else {
-      *data_writer->writer = DetachedBufferWriter(filename);
-    }
-  }
-
-  std::unique_ptr<DetachedBufferWriter> OpenDataWriter() {
-    return std::make_unique<DetachedBufferWriter>(
-        absl::StrCat(base_name_, "_", node()->name()->string_view(),
-                     "_data.part", part_number_, ".bfbs"));
-  }
-
-  const std::string base_name_;
-  const Configuration *const configuration_;
-  const UUID uuid_;
-
-  size_t part_number_ = 0;
-
-  // File to write both delivery timestamps and local data to.
-  std::unique_ptr<DetachedBufferWriter> data_writer_;
-
-  std::map<const Channel *, DataWriter> data_writers_;
-};
-
 // Logs all channels available in the event loop to disk every 100 ms.
 // Start by logging one message per channel to capture any state and
 // configuration that is sent rately on a channel and would affect execution.