From 58e5f3e78baf93ac233e77b377728b98d029ed6a Mon Sep 17 00:00:00 2001
From: George Tankersley <george.tankersley@gmail.com>
Date: Fri, 28 Sep 2018 00:52:40 +0000
Subject: [PATCH] parser: implement whole-block parsing and publicize
 constructors

---
 parser/block.go             | 47 +++++++++++++++++++++++++++++++++++++
 parser/block_header.go      |  2 +-
 parser/block_header_test.go |  2 +-
 parser/block_test.go        | 42 +++++++++++++++++++++++++++++++++
 parser/transaction.go       |  2 +-
 parser/transaction_test.go  |  4 ++--
 6 files changed, 94 insertions(+), 5 deletions(-)
 create mode 100644 parser/block.go
 create mode 100644 parser/block_test.go

diff --git a/parser/block.go b/parser/block.go
new file mode 100644
index 0000000..0d4893f
--- /dev/null
+++ b/parser/block.go
@@ -0,0 +1,47 @@
+package parser
+
+import (
+	"fmt"
+
+	"github.com/gtank/ctxd/parser/internal/bytestring"
+	"github.com/pkg/errors"
+)
+
+type block struct {
+	hdr *blockHeader
+	vtx []*transaction
+}
+
+func NewBlock() *block {
+	return &block{}
+}
+
+func (b *block) ParseFromSlice(data []byte) (rest []byte, err error) {
+	hdr := NewBlockHeader()
+	data, err = hdr.ParseFromSlice(data)
+	if err != nil {
+		return nil, errors.Wrap(err, "parsing block header")
+	}
+
+	s := bytestring.String(data)
+	var txCount int
+	if ok := s.ReadCompactSize(&txCount); !ok {
+		return nil, errors.New("could not read tx_count")
+	}
+	data = []byte(s)
+
+	vtx := make([]*transaction, 0, txCount)
+	for i := 0; len(data) > 0; i++ {
+		tx := NewTransaction()
+		data, err = tx.ParseFromSlice(data)
+		if err != nil {
+			return nil, errors.Wrap(err, fmt.Sprintf("parsing transaction %d", i))
+		}
+		vtx = append(vtx, tx)
+	}
+
+	b.hdr = hdr
+	b.vtx = vtx
+
+	return data, nil
+}
diff --git a/parser/block_header.go b/parser/block_header.go
index 39294d7..739116a 100644
--- a/parser/block_header.go
+++ b/parser/block_header.go
@@ -79,7 +79,7 @@ func (hdr *rawBlockHeader) MarshalBinary() ([]byte, error) {
 	return backing[:SER_BLOCK_HEADER_SIZE], nil
 }
 
-func newBlockHeader() *blockHeader {
+func NewBlockHeader() *blockHeader {
 	return &blockHeader{
 		rawBlockHeader: new(rawBlockHeader),
 	}
diff --git a/parser/block_header_test.go b/parser/block_header_test.go
index 4d87d39..400a296 100644
--- a/parser/block_header_test.go
+++ b/parser/block_header_test.go
@@ -72,7 +72,7 @@ func TestBlockHeader(t *testing.T) {
 			continue
 		}
 
-		blockHeader := newBlockHeader()
+		blockHeader := NewBlockHeader()
 		_, err = blockHeader.ParseFromSlice(blockData)
 		if err != nil {
 			t.Error(err)
diff --git a/parser/block_test.go b/parser/block_test.go
new file mode 100644
index 0000000..629a895
--- /dev/null
+++ b/parser/block_test.go
@@ -0,0 +1,42 @@
+package parser
+
+import (
+	"bufio"
+	"encoding/hex"
+	"fmt"
+	"os"
+	"testing"
+
+	"github.com/pkg/errors"
+)
+
+func TestBlockParser(t *testing.T) {
+	testBlocks, err := os.Open("testdata/blocks")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer testBlocks.Close()
+
+	scan := bufio.NewScanner(testBlocks)
+	for i := 0; scan.Scan(); i++ {
+		blockDataHex := scan.Text()
+		blockData, err := hex.DecodeString(blockDataHex)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		block := NewBlock()
+		blockData, err = block.ParseFromSlice(blockData)
+		if err != nil {
+			t.Error(errors.Wrap(err, fmt.Sprintf("parsing block %d", i)))
+			continue
+		}
+
+		// Some basic sanity checks
+		if block.hdr.Version != 4 {
+			t.Error("Read wrong version in a test block.")
+			break
+		}
+	}
+}
diff --git a/parser/transaction.go b/parser/transaction.go
index 03318e7..d0a3af7 100644
--- a/parser/transaction.go
+++ b/parser/transaction.go
@@ -394,7 +394,7 @@ func (tx *transaction) ParseFromSlice(data []byte) ([]byte, error) {
 	return []byte(s), nil
 }
 
-func newTransaction() *transaction {
+func NewTransaction() *transaction {
 	return &transaction{
 		rawTransaction: new(rawTransaction),
 	}
diff --git a/parser/transaction_test.go b/parser/transaction_test.go
index da78adf..0e851f4 100644
--- a/parser/transaction_test.go
+++ b/parser/transaction_test.go
@@ -179,7 +179,7 @@ func TestSproutTransactionParser(t *testing.T) {
 	}
 
 	for i, tt := range zip143tests {
-		tx := newTransaction()
+		tx := NewTransaction()
 
 		rest, err := tx.ParseFromSlice(rawTxData[i])
 		if err != nil {
@@ -685,7 +685,7 @@ func TestSaplingTransactionParser(t *testing.T) {
 	}
 
 	for i, tt := range zip243tests {
-		tx := newTransaction()
+		tx := NewTransaction()
 
 		rest, err := tx.ParseFromSlice(rawTxData[i])
 		if err != nil {