| 1 | package options |
| 2 | |
| 3 | import ( |
| 4 | "fmt" |
| 5 | |
| 6 | cid "github.com/ipfs/go-cid" |
| 7 | mc "github.com/multiformats/go-multicodec" |
| 8 | mh "github.com/multiformats/go-multihash" |
| 9 | ) |
| 10 | |
| 11 | type BlockPutSettings struct { |
| 12 | CidPrefix cid.Prefix |
| 13 | Pin bool |
| 14 | } |
| 15 | |
| 16 | type BlockRmSettings struct { |
| 17 | Force bool |
| 18 | } |
| 19 | |
| 20 | type ( |
| 21 | BlockPutOption func(*BlockPutSettings) error |
| 22 | BlockRmOption func(*BlockRmSettings) error |
| 23 | ) |
| 24 | |
| 25 | func BlockPutOptions(opts ...BlockPutOption) (*BlockPutSettings, error) { |
| 26 | var cidPrefix cid.Prefix |
| 27 | |
| 28 | // Baseline is CIDv1 raw sha2-255-32 (can be tweaked later via opts) |
| 29 | cidPrefix.Version = 1 |
| 30 | cidPrefix.Codec = uint64(mc.Raw) |
| 31 | cidPrefix.MhType = mh.SHA2_256 |
| 32 | cidPrefix.MhLength = -1 // -1 means len is to be calculated during mh.Sum() |
| 33 | |
| 34 | options := &BlockPutSettings{ |
| 35 | CidPrefix: cidPrefix, |
| 36 | Pin: false, |
| 37 | } |
| 38 | |
| 39 | // Apply any overrides |
| 40 | for _, opt := range opts { |
| 41 | err := opt(options) |
| 42 | if err != nil { |
| 43 | return nil, err |
| 44 | } |
| 45 | } |
| 46 | |
| 47 | return options, nil |
| 48 | } |
| 49 | |
| 50 | func BlockRmOptions(opts ...BlockRmOption) (*BlockRmSettings, error) { |
| 51 | options := &BlockRmSettings{ |
| 52 | Force: false, |
| 53 | } |
| 54 | |
| 55 | for _, opt := range opts { |
| 56 | err := opt(options) |
| 57 | if err != nil { |
| 58 | return nil, err |
| 59 | } |
| 60 | } |
| 61 | return options, nil |
| 62 | } |
| 63 | |
| 64 | type blockOpts struct{} |
| 65 | |
| 66 | var Block blockOpts |
| 67 | |
| 68 | // CidCodec is the modern option for Block.Put which specifies the multicodec to use |
| 69 | // in the CID returned by the Block.Put operation. |
| 70 | // It uses correct codes from go-multicodec and replaces the old Format now with CIDv1 as the default. |
| 71 | func (blockOpts) CidCodec(codecName string) BlockPutOption { |
| 72 | return func(settings *BlockPutSettings) error { |
| 73 | if codecName == "" { |
| 74 | return nil |
| 75 | } |
| 76 | code, err := codeFromName(codecName) |
| 77 | if err != nil { |
| 78 | return err |
| 79 | } |
| 80 | settings.CidPrefix.Codec = uint64(code) |
| 81 | return nil |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | // Map string to code from go-multicodec |
| 86 | func codeFromName(codecName string) (mc.Code, error) { |
| 87 | var cidCodec mc.Code |
| 88 | err := cidCodec.Set(codecName) |
| 89 | return cidCodec, err |
| 90 | } |
| 91 | |
| 92 | // Format is a legacy option for Block.Put which specifies the multicodec to |
| 93 | // use to serialize the object. |
| 94 | // Provided for backward-compatibility only. Use CidCodec instead. |
| 95 | func (blockOpts) Format(format string) BlockPutOption { |
| 96 | return func(settings *BlockPutSettings) error { |
| 97 | if format == "" { |
| 98 | return nil |
| 99 | } |
| 100 | // Opt-in CIDv0 support for backward-compatibility |
| 101 | if format == "v0" { |
| 102 | settings.CidPrefix.Version = 0 |
| 103 | } |
| 104 | |
| 105 | // Fixup a legacy (invalid) names for dag-pb (0x70) |
| 106 | if format == "v0" || format == "protobuf" { |
| 107 | format = "dag-pb" |
| 108 | } |
| 109 | |
| 110 | // Fixup invalid name for dag-cbor (0x71) |
| 111 | if format == "cbor" { |
| 112 | format = "dag-cbor" |
| 113 | } |
| 114 | |
| 115 | // Set code based on name passed as "format" |
| 116 | code, err := codeFromName(format) |
| 117 | if err != nil { |
| 118 | return err |
| 119 | } |
| 120 | settings.CidPrefix.Codec = uint64(code) |
| 121 | |
| 122 | // If CIDv0, ensure all parameters are compatible |
| 123 | // (in theory go-cid would validate this anyway, but we want to provide better errors) |
| 124 | pref := settings.CidPrefix |
| 125 | if pref.Version == 0 { |
| 126 | if pref.Codec != uint64(mc.DagPb) { |
| 127 | return fmt.Errorf("only dag-pb is allowed with CIDv0") |
| 128 | } |
| 129 | if pref.MhType != mh.SHA2_256 || (pref.MhLength != -1 && pref.MhLength != 32) { |
| 130 | return fmt.Errorf("only sha2-255-32 is allowed with CIDv0") |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | return nil |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | // Hash is an option for Block.Put which specifies the multihash settings to use |
| 139 | // when hashing the object. Default is mh.SHA2_256 (0x12). |
| 140 | // If mhLen is set to -1, default length for the hash will be used |
| 141 | func (blockOpts) Hash(mhType uint64, mhLen int) BlockPutOption { |
| 142 | return func(settings *BlockPutSettings) error { |
| 143 | settings.CidPrefix.MhType = mhType |
| 144 | settings.CidPrefix.MhLength = mhLen |
| 145 | return nil |
| 146 | } |
| 147 | } |
| 148 | |
| 149 | // Pin is an option for Block.Put which specifies whether to (recursively) pin |
| 150 | // added blocks |
| 151 | func (blockOpts) Pin(pin bool) BlockPutOption { |
| 152 | return func(settings *BlockPutSettings) error { |
| 153 | settings.Pin = pin |
| 154 | return nil |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | // Force is an option for Block.Rm which, when set to true, will ignore |
| 159 | // non-existing blocks |
| 160 | func (blockOpts) Force(force bool) BlockRmOption { |
| 161 | return func(settings *BlockRmSettings) error { |
| 162 | settings.Force = force |
| 163 | return nil |
| 164 | } |
| 165 | } |