colblk: rename DataBlockWriter/Reader to Encoder/Decoder

These names are more appropriate because these types don't actually
perform any reading or writing, and there are other associated reader
and writer types.

sstable/colblk/cockroach_test.go

@@ -183,7 +183,7 @@ var cockroachKeySeekerPool = sync.Pool{
 }
 
 type cockroachKeySeeker struct {
-	reader          *DataBlockReader
+	reader          *DataBlockDecoder
 	roachKeys       PrefixBytes
 	mvccWallTimes   UnsafeUints
 	mvccLogical     UnsafeUints
@@ -194,7 +194,7 @@ type cockroachKeySeeker struct {
 var _ KeySeeker = (*cockroachKeySeeker)(nil)
 
 // Init is part of the KeySeeker interface.
-func (ks *cockroachKeySeeker) Init(r *DataBlockReader) error {
+func (ks *cockroachKeySeeker) Init(r *DataBlockDecoder) error {
 	ks.reader = r
 	ks.roachKeys = r.r.PrefixBytes(cockroachColRoachKey)
 	ks.mvccWallTimes = r.r.Uints(cockroachColMVCCWallTime)
@@ -403,7 +403,7 @@ func TestCockroachDataBlock(t *testing.T) {
 		BaseWallTime:      seed,
 	}, valueLen)
 
-	var reader DataBlockReader
+	var reader DataBlockDecoder
 	var it DataBlockIter
 	it.InitOnce(cockroachKeySchema, crdbtest.Compare, crdbtest.Split, getLazyValuer(func([]byte) base.LazyValue {
 		return base.LazyValue{ValueOrHandle: []byte("mock external value")}
@@ -450,7 +450,7 @@ func generateDataBlock(
 ) (data []byte, keys [][]byte, values [][]byte) {
 	keys, values = crdbtest.RandomKVs(rng, targetBlockSize/valueLen, cfg, valueLen)
 
-	var w DataBlockWriter
+	var w DataBlockEncoder
 	w.Init(cockroachKeySchema)
 	count := 0
 	for w.Size() < targetBlockSize {
@@ -492,7 +492,7 @@ func benchmarkCockroachDataBlockWriter(b *testing.B, keyConfig crdbtest.KeyConfi
 	rng := rand.New(rand.NewSource(seed))
 	_, keys, values := generateDataBlock(rng, targetBlockSize, keyConfig, valueLen)
 
-	var w DataBlockWriter
+	var w DataBlockEncoder
 	w.Init(cockroachKeySchema)
 
 	b.ResetTimer()
@@ -629,7 +629,7 @@ func benchmarkCockroachDataBlockIter(
 
 	serializedBlock, keys, _ := generateDataBlock(rng, targetBlockSize, cfg.KeyConfig, cfg.ValueLen)
 
-	var reader DataBlockReader
+	var reader DataBlockDecoder
 	var it DataBlockIter
 	it.InitOnce(cockroachKeySchema, crdbtest.Compare, crdbtest.Split, getLazyValuer(func([]byte) base.LazyValue {
 		return base.LazyValue{ValueOrHandle: []byte("mock external value")}

sstable/colblk/data_block.go

@@ -30,7 +30,7 @@ import (
 //
 // TODO(jackson): Consider making this KVSchema. It feels like there's an
 // opportunity to generalize the ShortAttribute so that when a value is stored
-// out-of-band, the DataBlockWriter calls user-provided code to store the short
+// out-of-band, the DataBlockEncoder calls user-provided code to store the short
 // attributes inlined within the data block. For inlined-values, the
 // user-defined value columns would be implicitly null.
 type KeySchema struct {
@@ -98,8 +98,8 @@ func (kcmp KeyComparison) PrefixEqual() bool { return kcmp.PrefixLen == kcmp.Com
 // goroutines. In practice, multiple DataBlockIterators may use the same
 // KeySeeker.
 type KeySeeker interface {
-	// Init initializes the iterator to read from the provided DataBlockReader.
-	Init(b *DataBlockReader) error
+	// Init initializes the iterator to read from the provided DataBlockDecoder.
+	Init(b *DataBlockDecoder) error
 	// IsLowerBound returns true if all keys in the data block (after suffix
 	// replacement if syntheticSuffix is not empty) are >= the given key. If the
 	// data block contains no keys, returns true.
@@ -296,13 +296,13 @@ var _ KeySeeker = (*defaultKeySeeker)(nil)
 
 type defaultKeySeeker struct {
 	comparer     *base.Comparer
-	reader       *DataBlockReader
+	reader       *DataBlockDecoder
 	prefixes     PrefixBytes
 	suffixes     RawBytes
 	sharedPrefix []byte
 }
 
-func (ks *defaultKeySeeker) Init(r *DataBlockReader) error {
+func (ks *defaultKeySeeker) Init(r *DataBlockDecoder) error {
 	ks.reader = r
 	ks.prefixes = r.r.PrefixBytes(defaultKeySchemaColumnPrefix)
 	ks.suffixes = r.r.RawBytes(defaultKeySchemaColumnSuffix)
@@ -404,9 +404,8 @@ func (ks *defaultKeySeeker) Release() {
 	defaultKeySeekerPool.Put(ks)
 }
 
-// DataBlockWriter writes columnar data blocks, encoding keys using a
-// user-defined schema.
-type DataBlockWriter struct {
+// DataBlockEncoder encodes columnar data blocks using a user-defined schema.
+type DataBlockEncoder struct {
 	Schema    KeySchema
 	KeyWriter KeyWriter
 	// trailers is the column writer for InternalKey uint64 trailers.
@@ -451,7 +450,7 @@ const (
 const dataBlockCustomHeaderSize = 4
 
 // Init initializes the data block writer.
-func (w *DataBlockWriter) Init(schema KeySchema) {
+func (w *DataBlockEncoder) Init(schema KeySchema) {
 	w.Schema = schema
 	w.KeyWriter = schema.NewKeyWriter()
 	w.trailers.Init()
@@ -466,7 +465,7 @@ func (w *DataBlockWriter) Init(schema KeySchema) {
 }
 
 // Reset resets the data block writer to its initial state, retaining buffers.
-func (w *DataBlockWriter) Reset() {
+func (w *DataBlockEncoder) Reset() {
 	w.KeyWriter.Reset()
 	w.trailers.Reset()
 	w.prefixSame.Reset()
@@ -479,8 +478,8 @@ func (w *DataBlockWriter) Reset() {
 	w.enc.reset()
 }
 
-// String outputs a human-readable summary of internal DataBlockWriter state.
-func (w *DataBlockWriter) String() string {
+// String outputs a human-readable summary of internal DataBlockEncoder state.
+func (w *DataBlockEncoder) String() string {
 	var buf bytes.Buffer
 	size := uint32(w.Size())
 	fmt.Fprintf(&buf, "size=%d:\n", size)
@@ -517,7 +516,7 @@ func (w *DataBlockWriter) String() string {
 //
 // The caller is required to pass this in because in expected use cases, the
 // caller will also require the same information.
-func (w *DataBlockWriter) Add(
+func (w *DataBlockEncoder) Add(
 	ikey base.InternalKey,
 	value []byte,
 	valuePrefix block.ValuePrefix,
@@ -549,12 +548,12 @@ func (w *DataBlockWriter) Add(
 }
 
 // Rows returns the number of rows in the current pending data block.
-func (w *DataBlockWriter) Rows() int {
+func (w *DataBlockEncoder) Rows() int {
 	return w.rows
 }
 
 // Size returns the size of the current pending data block.
-func (w *DataBlockWriter) Size() int {
+func (w *DataBlockEncoder) Size() int {
 	off := blockHeaderSize(len(w.Schema.ColumnTypes)+dataBlockColumnMax, dataBlockCustomHeaderSize)
 	off = w.KeyWriter.Size(w.rows, off)
 	off = w.trailers.Size(w.rows, off)
@@ -569,13 +568,13 @@ func (w *DataBlockWriter) Size() int {
 // Finish serializes the pending data block, including the first [rows] rows.
 // The value of [rows] must be Rows() or Rows()-1. The provided size must be the
 // size of the data block with the provided row count (i.e., the return value of
-// [Size] when DataBlockWriter.Rows() = [rows]).
+// [Size] when DataBlockEncoder.Rows() = [rows]).
 //
 // Finish the returns the serialized, uncompressed data block and the
 // InternalKey of the last key contained within the data block. The memory of
-// the lastKey's UserKey is owned by the DataBlockWriter. The caller must
+// the lastKey's UserKey is owned by the DataBlockEncoder. The caller must
 // copy it if they require it to outlive a Reset of the writer.
-func (w *DataBlockWriter) Finish(rows, size int) (finished []byte, lastKey base.InternalKey) {
+func (w *DataBlockEncoder) Finish(rows, size int) (finished []byte, lastKey base.InternalKey) {
 	if invariants.Enabled && rows != w.rows && rows != w.rows-1 {
 		panic(errors.AssertionFailedf("data block has %d rows; asked to finish %d", w.rows, rows))
 	}
@@ -617,8 +616,8 @@ func (w *DataBlockWriter) Finish(rows, size int) (finished []byte, lastKey base.
 type DataBlockRewriter struct {
 	KeySchema KeySchema
 
-	writer    DataBlockWriter
-	reader    DataBlockReader
+	writer    DataBlockEncoder
+	reader    DataBlockDecoder
 	iter      DataBlockIter
 	keySeeker KeySeeker
 	compare   base.Compare
@@ -734,14 +733,14 @@ func (rw *DataBlockRewriter) RewriteSuffixes(
 	return start, end, rewritten, nil
 }
 
-// DataBlockReaderSize is the size of a DataBlockReader struct. If allocating
+// DataBlockDecoderSize is the size of a DataBlockDecoder struct. If allocating
 // memory for a data block, the caller may want to additionally allocate memory
-// for the corresponding DataBlockReader.
-const DataBlockReaderSize = unsafe.Sizeof(DataBlockReader{})
+// for the corresponding DataBlockDecoder.
+const DataBlockDecoderSize = unsafe.Sizeof(DataBlockDecoder{})
 
-// A DataBlockReader holds state for reading a columnar data block. It may be
-// shared among multiple DataBlockIters.
-type DataBlockReader struct {
+// A DataBlockDecoder holds state for interpreting a columnar data block. It may
+// be shared among multiple DataBlockIters.
+type DataBlockDecoder struct {
 	r BlockReader
 	// trailers holds an array of the InternalKey trailers, encoding the key
 	// kind and sequence number of each key.
@@ -772,12 +771,12 @@ type DataBlockReader struct {
 }
 
 // BlockReader returns a pointer to the underlying BlockReader.
-func (r *DataBlockReader) BlockReader() *BlockReader {
+func (r *DataBlockDecoder) BlockReader() *BlockReader {
 	return &r.r
 }
 
 // Init initializes the data block reader with the given serialized data block.
-func (r *DataBlockReader) Init(schema KeySchema, data []byte) {
+func (r *DataBlockDecoder) Init(schema KeySchema, data []byte) {
 	r.r.Init(data, dataBlockCustomHeaderSize)
 	r.trailers = r.r.Uints(len(schema.ColumnTypes) + dataBlockColumnTrailer)
 	r.prefixChanged = r.r.Bitmap(len(schema.ColumnTypes) + dataBlockColumnPrefixChanged)
@@ -789,7 +788,7 @@ func (r *DataBlockReader) Init(schema KeySchema, data []byte) {
 
 // Describe descirbes the binary format of the data block, assuming f.Offset()
 // is positioned at the beginning of the same data block described by r.
-func (r *DataBlockReader) Describe(f *binfmt.Formatter) {
+func (r *DataBlockDecoder) Describe(f *binfmt.Formatter) {
 	// Set the relative offset. When loaded into memory, the beginning of blocks
 	// are aligned. Padding that ensures alignment is done relative to the
 	// current offset. Setting the relative offset ensures that if we're
@@ -828,7 +827,7 @@ type DataBlockIter struct {
 	// -- Fields that are initialized for each block --
 	// For any changes to these fields, InitHandle should be updated.
 
-	r            *DataBlockReader
+	r            *DataBlockDecoder
 	h            block.BufferHandle
 	maxRow       int
 	transforms   block.IterTransforms
@@ -849,7 +848,7 @@ type DataBlockIter struct {
 	// iteration.
 	nextObsoletePoint int
 
-	readerAlloc DataBlockReader
+	readerAlloc DataBlockDecoder
 }
 
 // InitOnce configures the data block iterator's key schema and lazy value
@@ -869,7 +868,7 @@ func (i *DataBlockIter) InitOnce(
 
 // Init initializes the data block iterator, configuring it to read from the
 // provided reader.
-func (i *DataBlockIter) Init(r *DataBlockReader, transforms block.IterTransforms) error {
+func (i *DataBlockIter) Init(r *DataBlockDecoder, transforms block.IterTransforms) error {
 	i.r = r
 	// Leave i.h unchanged.
 	numRows := int(r.r.header.Rows)
@@ -1364,6 +1363,6 @@ func (i *DataBlockIter) Close() error {
 	i.h = block.BufferHandle{}
 	i.transforms = block.IterTransforms{}
 	i.kv = base.InternalKV{}
-	i.readerAlloc = DataBlockReader{}
+	i.readerAlloc = DataBlockDecoder{}
 	return nil
 }

sstable/colblk/data_block_test.go

@@ -25,8 +25,8 @@ var testKeysSchema = DefaultKeySchema(testkeys.Comparer, 16)
 
 func TestDataBlock(t *testing.T) {
 	var buf bytes.Buffer
-	var w DataBlockWriter
-	var r DataBlockReader
+	var w DataBlockEncoder
+	var r DataBlockDecoder
 	var it DataBlockIter
 	rw := NewDataBlockRewriter(testKeysSchema, testkeys.Comparer.Compare, testkeys.Comparer.Split)
 	var sizes []int
@@ -149,7 +149,7 @@ func benchmarkDataBlockWriter(b *testing.B, prefixSize, valueSize int) {
 	rng := rand.New(rand.NewSource(seed))
 	keys, values := makeTestKeyRandomKVs(rng, prefixSize, valueSize, targetBlockSize)
 
-	var w DataBlockWriter
+	var w DataBlockEncoder
 	w.Init(testKeysSchema)
 	b.ResetTimer()
 

sstable/colblk_writer.go

@@ -42,7 +42,7 @@ type RawColumnWriter struct {
 	props                Properties
 	// block writers buffering unflushed data.
 	dataBlock struct {
-		colblk.DataBlockWriter
+		colblk.DataBlockEncoder
 		// numDeletions stores the count of point tombstones in this data block.
 		// It's used to determine if this data block is considered
 		// tombstone-dense for the purposes of compaction.

sstable/colblk_writer_test.go

@@ -115,7 +115,7 @@ func describeSSTableBinary(f *binfmt.Formatter, schema colblk.KeySchema) error {
 					f.HexBytesln(block.TrailerLen, "%s block trailer", bh.Name)
 					continue
 				case "data":
-					var r colblk.DataBlockReader
+					var r colblk.DataBlockDecoder
 					// NB: The byte slice used to Init must be aligned (like an
 					// allocated block would be in practice).
 					r.Init(schema, aligned.Copy(f.Data()[bh.Offset:bh.Offset+bh.Length]))

sstable/layout.go

@@ -322,7 +322,7 @@ func formatColblkDataBlock(
 	data []byte,
 	fmtRecord func(key *base.InternalKey, value []byte),
 ) error {
-	var reader colblk.DataBlockReader
+	var reader colblk.DataBlockDecoder
 	reader.Init(r.keySchema, data)
 	f := binfmt.New(data)
 	f.SetLinePrefix("               ")