added

vendor/github.com/glycerine/zygomys/zygo/bsave.go

@@ -0,0 +1,128 @@
+package zygo
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+
+	"github.com/glycerine/greenpack/msgp"
+)
+
+// (bsave value path) writes value as greenpack to file.
+//
+// (greenpack value) writes value as greenpack to SexpRaw in memory.
+//
+// bsave converts to binary with (togo) then saves the binary to file.
+func WriteShadowGreenpackToFileFunction(env *Zlisp, name string, args []Sexp) (Sexp, error) {
+	narg := len(args)
+	if narg < 1 || narg > 2 {
+		return SexpNull, WrongNargs
+	}
+	// check arg[0]
+	var asHash *SexpHash
+	switch x := args[0].(type) {
+	default:
+		return SexpNull, fmt.Errorf("%s error: top value must be a hash or defmap; we see '%T'", name, args[0])
+	case *SexpHash:
+		// okay, good
+		asHash = x
+	}
+
+	switch name {
+	case "bsave":
+		if narg != 2 {
+			return SexpNull, WrongNargs
+		}
+
+	case "greenpack":
+		if narg != 1 {
+			return SexpNull, WrongNargs
+		}
+		var buf bytes.Buffer
+		_, err := toGreenpackHelper(env, asHash, &buf, "memory")
+		if err != nil {
+			return SexpNull, err
+		}
+		return &SexpRaw{Val: buf.Bytes()}, nil
+	}
+
+	// check arg[1]
+	var fn string
+	switch fna := args[1].(type) {
+	case *SexpStr:
+		fn = fna.S
+	default:
+		return SexpNull, fmt.Errorf("error: %s requires a string (SexpStr) path to write to as the second argument. we got type %T / value = %v", name, args[1], args[1])
+	}
+
+	// don't overwrite existing file
+	if FileExists(fn) {
+		return SexpNull, fmt.Errorf("error: %s refusing to write to existing file '%s'",
+			name, fn)
+	}
+
+	f, err := os.Create(fn)
+	if err != nil {
+		return SexpNull, fmt.Errorf("error: %s sees error trying to create file '%s': '%v'", name, fn, err)
+	}
+	defer f.Close()
+
+	_, err = toGreenpackHelper(env, asHash, f, fn)
+	return SexpNull, err
+}
+
+func toGreenpackHelper(env *Zlisp, asHash *SexpHash, f io.Writer, fn string) (Sexp, error) {
+
+	// create shadow structs
+	_, err := ToGoFunction(env, "togo", []Sexp{asHash})
+	if err != nil {
+		return SexpNull, fmt.Errorf("ToGo call sees error: '%v'", err)
+	}
+
+	if asHash.GoShadowStruct == nil {
+		return SexpNull, fmt.Errorf("GoShadowStruct was nil, on attempt to write to '%s'", fn)
+	}
+
+	enc, ok := interface{}(asHash.GoShadowStruct).(msgp.Encodable)
+	if !ok {
+		return SexpNull, fmt.Errorf("error: GoShadowStruct was not greenpack Encodable -- run `go generate` or add greenpack to the source file for type '%T'. on attempt to save to '%s'", asHash.GoShadowStruct, fn)
+	}
+	w := msgp.NewWriter(f)
+	err = msgp.Encode(w, enc)
+	if err != nil {
+		return SexpNull, fmt.Errorf("error: greenpack encoding to file '%s' of type '%T' sees error '%v'", fn, asHash.GoShadowStruct, err)
+	}
+	err = w.Flush()
+	return SexpNull, err
+}
+
+func ReadGreenpackFromFileFunction(env *Zlisp, name string, args []Sexp) (Sexp, error) {
+	narg := len(args)
+
+	if narg != 1 {
+		return SexpNull, WrongNargs
+	}
+	var fn string
+	switch fna := args[0].(type) {
+	case *SexpStr:
+		fn = fna.S
+	default:
+		return SexpNull, fmt.Errorf("%s requires a string path to read. we got type %T / value = %v", name, args[0], args[0])
+	}
+
+	if !FileExists(string(fn)) {
+		return SexpNull, fmt.Errorf("file '%s' does not exist", fn)
+	}
+	f, err := os.Open(fn)
+	if err != nil {
+		return SexpNull, err
+	}
+	defer f.Close()
+	by, err := ioutil.ReadAll(f)
+	if err != nil {
+		return SexpNull, err
+	}
+	return MsgpackToSexp(by, env)
+}