Method Read

be/src/runtime/io/data-cache.cc:263–276

Reads from byte offset 'offset' for 'bytes_to_read' bytes into 'buffer'. Returns true iff read succeeded. Returns false on error or if the file is already closed.

  // Returns true iff read succeeded. Returns false on error or if the file
  // is already closed.
  bool Read(int64_t offset, uint8_t* buffer, int64_t bytes_to_read) {
    DCHECK_EQ(offset % PAGE_SIZE, 0);
    // Hold the lock in shared mode to check if 'file_' is not closed already.
    kudu::shared_lock<rw_spinlock> lock(lock_.get_lock());
    if (UNLIKELY(!file_)) return false;
    DCHECK_LE(offset + bytes_to_read, current_offset_.Load());
    kudu::Status status = file_->Read(offset, Slice(buffer, bytes_to_read));
    if (UNLIKELY(!status.ok())) {
      LOG(ERROR) << Substitute("Failed to read from $0 at offset $1 for $2 bytes: $3",
          path_, offset, PrettyPrinter::PrintBytes(bytes_to_read), status.ToString());
      return false;
    }
    return true;
  }

  // Writes 'buffer' of length 'buffer_len' into  byte offset 'offset' in the file.
  // Returns true iff write succeeded. Returns false on errors or if the file is