payments: rename p2data to embed

src/payments/embed.js

@@ -0,0 +1,56 @@
+const lazy = require('./lazy')
+const typef = require('typeforce')
+const OPS = require('bitcoin-ops')
+
+const bscript = require('../script')
+const BITCOIN_NETWORK = require('../networks').bitcoin
+
+function stacksEqual (a, b) {
+  if (a.length !== b.length) return false
+
+  return a.every(function (x, i) {
+    return x.equals(b[i])
+  })
+}
+
+// output: OP_RETURN ...
+function p2data (a, opts) {
+  if (
+    !a.data &&
+    !a.output
+  ) throw new TypeError('Not enough data')
+  opts = opts || { validate: true }
+
+  typef({
+    network: typef.maybe(typef.Object),
+    output: typef.maybe(typef.Buffer),
+    data: typef.maybe(typef.arrayOf(typef.Buffer))
+  }, a)
+
+  const network = a.network || BITCOIN_NETWORK
+  const o = { network }
+
+  lazy.prop(o, 'output', function () {
+    if (!a.data) return
+    return bscript.compile([OPS.OP_RETURN].concat(a.data))
+  })
+  lazy.prop(o, 'data', function () {
+    if (!a.output) return
+    return bscript.decompile(a.output).slice(1)
+  })
+
+  // extended validation
+  if (opts.validate) {
+    if (a.output) {
+      const chunks = bscript.decompile(a.output)
+      if (chunks[0] !== OPS.OP_RETURN) throw new TypeError('Output is invalid')
+      if (!chunks.slice(1).every(typef.Buffer)) throw new TypeError('Output is invalid')
+
+      if (a.data && !stacksEqual(a.data, o.data)) throw new TypeError('Data mismatch')
+    }
+  }
+
+  return Object.assign(o, a)
+}
+
+module.exports = p2data