tangara-fw/src/database/song.cpp

#include "song.hpp"

#include <esp_log.h>
#include <ff.h>
#include <komihash.h>
#include <tags.h>

namespace database {

namespace libtags {

struct Aux {
  FIL file;
  FILINFO info;
  SongTags* tags;
};

static int read(Tagctx* ctx, void* buf, int cnt) {
  Aux* aux = reinterpret_cast<Aux*>(ctx->aux);
  UINT bytes_read;
  if (f_read(&aux->file, buf, cnt, &bytes_read) != FR_OK) {
    return -1;
  }
  return bytes_read;
}

static int seek(Tagctx* ctx, int offset, int whence) {
  Aux* aux = reinterpret_cast<Aux*>(ctx->aux);
  FRESULT res;
  if (whence == 0) {
    // Seek from the start of the file. This is f_lseek's behaviour.
    res = f_lseek(&aux->file, offset);
  } else if (whence == 1) {
    // Seek from current offset.
    res = f_lseek(&aux->file, aux->file.fptr + offset);
  } else if (whence == 2) {
    // Seek from the end of the file
    res = f_lseek(&aux->file, aux->info.fsize + offset);
  } else {
    return -1;
  }
  return res;
}

static void tag(Tagctx* ctx,
                int t,
                const char* k,
                const char* v,
                int offset,
                int size,
                Tagread f) {
  Aux* aux = reinterpret_cast<Aux*>(ctx->aux);
  if (t == Ttitle) {
    aux->tags->title = v;
  } else if (t == Tartist) {
    aux->tags->artist = v;
  } else if (t == Talbum) {
    aux->tags->album = v;
  }
}

static void toc(Tagctx* ctx, int ms, int offset) {}

}  // namespace libtags

static const std::size_t kBufSize = 1024;
static const char* kTag = "TAGS";

auto ReadAndParseTags(const std::string& path, SongTags* out) -> bool {
  libtags::Aux aux;
  aux.tags = out;
  if (f_stat(path.c_str(), &aux.info) != FR_OK ||
      f_open(&aux.file, path.c_str(), FA_READ) != FR_OK) {
    ESP_LOGW(kTag, "failed to open file %s", path.c_str());
    return false;
  }
  // Fine to have this on the stack; this is only called on the leveldb task.
  char buf[kBufSize];
  Tagctx ctx;
  ctx.read = libtags::read;
  ctx.seek = libtags::seek;
  ctx.tag = libtags::tag;
  ctx.toc = libtags::toc;
  ctx.aux = &aux;
  ctx.buf = buf;
  ctx.bufsz = kBufSize;
  int res = tagsget(&ctx);
  f_close(&aux.file);

  if (res != 0) {
    // Parsing failed.
    return false;
  }

  switch (ctx.format) {
    case Fmp3:
      out->encoding = ENC_MP3;
      break;
    default:
      out->encoding = ENC_UNSUPPORTED;
  }

  return true;
}

auto HashString(komihash_stream_t* stream, std::string str) -> void {
  komihash_stream_update(stream, str.c_str(), str.length());
}

auto SongTags::Hash() const -> uint64_t {
  komihash_stream_t stream;
  komihash_stream_init(&stream, 0);
  HashString(&stream, title.value_or(""));
  HashString(&stream, artist.value_or(""));
  HashString(&stream, album.value_or(""));
  return komihash_stream_final(&stream);
}

auto SongData::UpdateHash(uint64_t new_hash) const -> SongData {
  return SongData(id_, filepath_, new_hash, play_count_, is_tombstoned_);
}

auto SongData::Entomb() const -> SongData {
  return SongData(id_, filepath_, tags_hash_, play_count_, true);
}

auto SongData::Exhume(const std::string& new_path) const -> SongData {
  return SongData(id_, new_path, tags_hash_, play_count_, false);
}

}  // namespace database