path: root/accounts/abi/type.go

// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package abi

import (
    "fmt"
    "reflect"
    "regexp"
    "strconv"

    "github.com/ethereum/go-ethereum/common"
)

const (
    IntTy byte = iota
    UintTy
    BoolTy
    StringTy
    SliceTy
    AddressTy
    FixedBytesTy
    BytesTy
    HashTy
    RealTy
)

// Type is the reflection of the supported argument type
type Type struct {
    IsSlice   bool
    SliceSize int

    Kind       reflect.Kind
    Type       reflect.Type
    Size       int
    T          byte   // Our own type checking
    stringKind string // holds the unparsed string for deriving signatures
}

var (
    fullTypeRegex = regexp.MustCompile("([a-zA-Z0-9]+)(\\[([0-9]*)?\\])?")
    typeRegex     = regexp.MustCompile("([a-zA-Z]+)([0-9]*)?")
)

// NewType returns a fully parsed Type given by the input string or an error if it  can't be parsed.
//
// Strings can be in the format of:
//
//  Input  = Type [ "[" [ Number ] "]" ] Name .
//  Type   = [ "u" ] "int" [ Number ] .
//
// Examples:
//
//      string     int       uint       real
//      string32   int8      uint8      uint[]
//      address    int256    uint256    real[2]
func NewType(t string) (typ Type, err error) {
    // 1. full string 2. type 3. (opt.) is slice 4. (opt.) size
    // parse the full representation of the abi-type definition; including:
    // * full string
    // * type
    //  * is slice
    //  * slice size
    res := fullTypeRegex.FindAllStringSubmatch(t, -1)[0]

    // check if type is slice and parse type.
    switch {
    case res[3] != "":
        // err is ignored. Already checked for number through the regexp
        typ.SliceSize, _ = strconv.Atoi(res[3])
        typ.IsSlice = true
    case res[2] != "":
        typ.IsSlice, typ.SliceSize = true, -1
    case res[0] == "":
        return Type{}, fmt.Errorf("abi: type parse error: %s", t)
    }

    // parse the type and size of the abi-type.
    parsedType := typeRegex.FindAllStringSubmatch(res[1], -1)[0]
    // varSize is the size of the variable
    var varSize int
    if len(parsedType[2]) > 0 {
        var err error
        varSize, err = strconv.Atoi(parsedType[2])
        if err != nil {
            return Type{}, fmt.Errorf("abi: error parsing variable size: %v", err)
        }
    }
    // varType is the parsed abi type
    varType := parsedType[1]
    // substitute canonical integer
    if varSize == 0 && (varType == "int" || varType == "uint") {
        varSize = 256
        t += "256"
    }

    switch varType {
    case "int":
        typ.Kind = reflect.Int
        typ.Type = big_t
        typ.Size = varSize
        typ.T = IntTy
    case "uint":
        typ.Kind = reflect.Uint
        typ.Type = ubig_t
        typ.Size = varSize
        typ.T = UintTy
    case "bool":
        typ.Kind = reflect.Bool
        typ.T = BoolTy
    case "real": // TODO
        typ.Kind = reflect.Invalid
    case "address":
        typ.Type = address_t
        typ.Size = 20
        typ.T = AddressTy
    case "string":
        typ.Kind = reflect.String
        typ.Size = -1
        typ.T = StringTy
        if varSize > 0 {
            typ.Size = 32
        }
    case "hash":
        typ.Kind = reflect.Array
        typ.Size = 32
        typ.Type = hash_t
        typ.T = HashTy
    case "bytes":
        typ.Kind = reflect.Array
        typ.Type = byte_ts
        typ.Size = varSize
        if varSize == 0 {
            typ.T = BytesTy
        } else {
            typ.T = FixedBytesTy
        }
    default:
        return Type{}, fmt.Errorf("unsupported arg type: %s", t)
    }
    typ.stringKind = t

    return
}

func (t Type) String() (out string) {
    return t.stringKind
}

// packBytesSlice packs the given bytes as [L, V] as the canonical representation
// bytes slice
func packBytesSlice(bytes []byte, l int) []byte {
    len := packNum(reflect.ValueOf(l), UintTy)
    return append(len, common.RightPadBytes(bytes, (l+31)/32*32)...)
}

// Test the given input parameter `v` and checks if it matches certain
// criteria
// * Big integers are checks for ptr types and if the given value is
//   assignable
// * Integer are checked for size
// * Strings, addresses and bytes are checks for type and size
func (t Type) pack(v interface{}) ([]byte, error) {
    value := reflect.ValueOf(v)
    switch kind := value.Kind(); kind {
    case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
        // check input is unsigned
        if t.Type != ubig_t {
            return nil, fmt.Errorf("abi: type mismatch: %s for %T", t.Type, v)
        }

        // no implicit type casting
        if int(value.Type().Size()*8) != t.Size {
            return nil, fmt.Errorf("abi: cannot use type %T as type uint%d", v, t.Size)
        }

        return packNum(value, t.T), nil
    case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
        if t.Type != ubig_t {
            return nil, fmt.Errorf("type mismatch: %s for %T", t.Type, v)
        }

        // no implicit type casting
        if int(value.Type().Size()*8) != t.Size {
            return nil, fmt.Errorf("abi: cannot use type %T as type uint%d", v, t.Size)
        }
        return packNum(value, t.T), nil
    case reflect.Ptr:
        // If the value is a ptr do a assign check (only used by
        // big.Int for now)
        if t.Type == ubig_t && value.Type() != ubig_t {
            return nil, fmt.Errorf("type mismatch: %s for %T", t.Type, v)
        }
        return packNum(value, t.T), nil
    case reflect.String:
        if t.Size > -1 && value.Len() > t.Size {
            return nil, fmt.Errorf("%v out of bound. %d for %d", value.Kind(), value.Len(), t.Size)
        }

        return packBytesSlice([]byte(value.String()), value.Len()), nil
    case reflect.Slice:
        // Byte slice is a special case, it gets treated as a single value
        if t.T == BytesTy {
            return packBytesSlice(value.Bytes(), value.Len()), nil
        }

        if t.SliceSize > -1 && value.Len() > t.SliceSize {
            return nil, fmt.Errorf("%v out of bound. %d for %d", value.Kind(), value.Len(), t.Size)
        }

        // Signed / Unsigned check
        if value.Type() == big_t && (t.T != IntTy && isSigned(value)) || (t.T == UintTy && isSigned(value)) {
            return nil, fmt.Errorf("slice of incompatible types.")
        }

        var packed []byte
        for i := 0; i < value.Len(); i++ {
            val, err := t.pack(value.Index(i).Interface())
            if err != nil {
                return nil, err
            }
            packed = append(packed, val...)
        }
        return packBytesSlice(packed, value.Len()), nil
    case reflect.Bool:
        if value.Bool() {
            return common.LeftPadBytes(common.Big1.Bytes(), 32), nil
        } else {
            return common.LeftPadBytes(common.Big0.Bytes(), 32), nil
        }
    case reflect.Array:
        if v, ok := value.Interface().(common.Address); ok {
            return common.LeftPadBytes(v[:], 32), nil
        } else if v, ok := value.Interface().(common.Hash); ok {
            return v[:], nil
        }
    }

    return nil, fmt.Errorf("ABI: bad input given %v", value.Kind())
}