Docs: golint-ify "importers" module

This fixes all golint warnings in the importers module, adding
documentation and module descriptions.

License: MIT
Signed-off-by: Hector Sanjuan <hector@protocol.ai>

parse.go

@@ -8,6 +8,9 @@ import (
 	"strings"
 )
 
+// FromString returns a Splitter depending on the given string:
+// it supports "default" (""), "size-{size}", "rabin", "rabin-{blocksize}" and
+// "rabin-{min}-{avg}-{max}".
 func FromString(r io.Reader, chunker string) (Splitter, error) {
 	switch {
 	case chunker == "" || chunker == "default":

rabin.go

@@ -7,13 +7,18 @@ import (
 	"github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/whyrusleeping/chunker"
 )
 
+// IpfsRabinPoly is the irreducible polynomial of degree 53 used by for Rabin.
 var IpfsRabinPoly = chunker.Pol(17437180132763653)
 
+// Rabin implements the Splitter interface and splits content with Rabin
+// fingerprints.
 type Rabin struct {
 	r      *chunker.Chunker
 	reader io.Reader
 }
 
+// NewRabin creates a new Rabin splitter with the given
+// average block size.
 func NewRabin(r io.Reader, avgBlkSize uint64) *Rabin {
 	min := avgBlkSize / 3
 	max := avgBlkSize + (avgBlkSize / 2)
@@ -21,6 +26,8 @@ func NewRabin(r io.Reader, avgBlkSize uint64) *Rabin {
 	return NewRabinMinMax(r, min, avgBlkSize, max)
 }
 
+// NewRabinMinMax returns a new Rabin splitter which uses
+// the given min, average and max block sizes.
 func NewRabinMinMax(r io.Reader, min, avg, max uint64) *Rabin {
 	h := fnv.New32a()
 	ch := chunker.New(r, IpfsRabinPoly, h, avg, min, max)
@@ -31,6 +38,7 @@ func NewRabinMinMax(r io.Reader, min, avg, max uint64) *Rabin {
 	}
 }
 
+// NextBytes reads the next bytes from the reader and returns a slice.
 func (r *Rabin) NextBytes() ([]byte, error) {
 	ch, err := r.r.Next()
 	if err != nil {
@@ -40,6 +48,7 @@ func (r *Rabin) NextBytes() ([]byte, error) {
 	return ch.Data, nil
 }
 
+// Reader returns the io.Reader associated to this Splitter.
 func (r *Rabin) Reader() io.Reader {
 	return r.reader
 }

rabin_test.go

@@ -68,7 +68,7 @@ func TestRabinChunkReuse(t *testing.T) {
 	ch2 := chunkData(t, data)
 
 	var extra int
-	for k, _ := range ch2 {
+	for k := range ch2 {
 		_, ok := ch1[k]
 		if !ok {
 			extra++

splitting.go

-// package chunk implements streaming block splitters
+// Package chunk implements streaming block splitters.
+// Splitters read data from a reader and provide byte slices (chunks)
+// The size and contents of these slices depend on the splitting method
+// used.
 package chunk
 
 import (
@@ -10,25 +13,34 @@ import (
 
 var log = logging.Logger("chunk")
 
+// DefaultBlockSize is the chunk size that splitters produce (or aim to).
 var DefaultBlockSize int64 = 1024 * 256
 
+// A Splitter reads bytes from a Reader and creates "chunks" (byte slices)
+// that can be used to build DAG nodes.
 type Splitter interface {
 	Reader() io.Reader
 	NextBytes() ([]byte, error)
 }
 
+// SplitterGen is a splitter generator, given a reader.
 type SplitterGen func(r io.Reader) Splitter
 
+// DefaultSplitter returns a SizeSplitter with the DefaultBlockSize.
 func DefaultSplitter(r io.Reader) Splitter {
 	return NewSizeSplitter(r, DefaultBlockSize)
 }
 
+// SizeSplitterGen returns a SplitterGen function which will create
+// a splitter with the given size when called.
 func SizeSplitterGen(size int64) SplitterGen {
 	return func(r io.Reader) Splitter {
 		return NewSizeSplitter(r, size)
 	}
 }
 
+// Chan returns a channel that receives each of the chunks produced
+// by a splitter, along with another one for errors.
 func Chan(s Splitter) (<-chan []byte, <-chan error) {
 	out := make(chan []byte)
 	errs := make(chan error, 1)
@@ -56,6 +68,7 @@ type sizeSplitterv2 struct {
 	err  error
 }
 
+// NewSizeSplitter returns a new size-based Splitter with the given block size.
 func NewSizeSplitter(r io.Reader, size int64) Splitter {
 	return &sizeSplitterv2{
 		r:    r,
@@ -63,6 +76,7 @@ func NewSizeSplitter(r io.Reader, size int64) Splitter {
 	}
 }
 
+// NextBytes produces a new chunk.
 func (ss *sizeSplitterv2) NextBytes() ([]byte, error) {
 	if ss.err != nil {
 		return nil, ss.err
@@ -85,6 +99,7 @@ func (ss *sizeSplitterv2) NextBytes() ([]byte, error) {
 	}
 }
 
+// Reader returns the io.Reader associated to this Splitter.
 func (ss *sizeSplitterv2) Reader() io.Reader {
 	return ss.r
 }