feat<descriptor>: added functions for generating scripts and addresses

lib/descriptor/abstractdescriptor.js

@@ -39,6 +39,7 @@ const stringType = {
  * (size 1 for PK, PKH, WPKH; any size for WSH and Multisig).
  * @property {AbstractDescriptor[]} subdescriptors - sub-descriptor arguments
  * for the descriptor (empty for everything but SH and WSH)
+ * @property {String} scriptContext
  * @property {Network} network
  */
 
@@ -52,6 +53,7 @@ class AbstractDescriptor {
     this.type = null;
     this.keyProviders = [];
     this.subdescriptors = [];
+    this.scriptContext = common.scriptContext.TOP;
     this.network = null;
   }
 
@@ -232,6 +234,58 @@ class AbstractDescriptor {
   isSingleType() {
     return true;
   }
+
+  /**
+   * Get scripts for the descriptor at a specified position.
+   * @param {Number} pos
+   * @returns {Script[]}
+   */
+
+  generateScripts(pos) {
+    const pubkeys = [];
+    const subscripts = [];
+
+    for (const subdesc of this.subdescriptors) {
+      const outscripts = subdesc.generateScripts(pos);
+      assert(outscripts.length === 1);
+      subscripts.push(outscripts[0]);
+    }
+
+    for (const provider of this.keyProviders) {
+      const pubkey = provider.getPublicKey(pos);
+      pubkeys.push(pubkey);
+    }
+
+    return this._getScripts(pubkeys, subscripts);
+  }
+
+  /**
+   * Get the scripts (helper function).
+   * @returns {Script[]}
+   */
+
+  _getScripts() {
+    throw new Error('Abstract method.');
+  }
+
+  /**
+   * Derive addresses for the descriptor at a specified position.
+   * @param {Number} pos
+   * @returns {Address[]}
+   */
+
+  getAddresses(pos) {
+    const scripts = this.generateScripts(pos);
+    const addresses = [];
+
+    for (const script of scripts) {
+      const address = script.getAddress();
+      assert(address, 'Descriptor does not have a corresponding address');
+      addresses.push(address.toString(this.network));
+    }
+
+    return addresses;
+  }
 }
 
 /*

lib/descriptor/type/addr.js

@@ -12,13 +12,15 @@ const common = require('../common');
 const {isType, strip, checkChecksum, scriptContext, types} = common;
 const Address = require('../../primitives/address');
 const Network = require('../../protocol/network');
+const Script = require('../../script/script');
 
 /**
  * AddressDescriptor
  * Represents the output script produced by the address in the descriptor.
  * @see https://github.com/bitcoin/bips/blob/master/bip-0385.mediawiki#addr
  * @property {String} type
  * @property {Address} address
+ * @property {String} scriptContext
  * @property {Network} network
  * @extends AbstractDescriptor
  */
@@ -118,6 +120,15 @@ class AddressDescriptor extends AbstractDescriptor {
   isSolvable() {
     return false;
   }
+
+  /**
+   * Get the scripts (helper function).
+   * @returns {Script[]}
+   */
+
+  _getScripts() {
+    return [Script.fromAddress(this.address)];
+  }
 }
 
 /*

lib/descriptor/type/combo.js

@@ -12,13 +12,16 @@ const common = require('../common');
 const {isType, strip, checkChecksum, scriptContext, types} = common;
 const KeyProvider = require('../keyprovider');
 const Network = require('../../protocol/network');
+const hash160 = require('bcrypto/lib/hash160');
+const Script = require('../../script/script');
 
 /**
  * ComboDescriptor
  * Represents a P2PK, P2PKH, P2WPKH, and P2SH-P2WPKH output scripts.
  * @see https://github.com/bitcoin/bips/blob/master/bip-0384.mediawiki
  * @property {String} type
  * @property {KeyProvider[]} keyProviders
+ * @property {String} scriptContext
  * @property {Network} network
  * @extends AbstractDescriptor
  */
@@ -112,6 +115,31 @@ class ComboDescriptor extends AbstractDescriptor {
   isSolvable() {
     return true;
   }
+
+  /**
+   * Get the scripts (helper function).
+   * @param {Buffer[]} pubkeys
+   * @returns {Script[]}
+   */
+
+  _getScripts(pubkeys) {
+    assert(Array.isArray(pubkeys) && pubkeys.length === 1);
+    assert(Buffer.isBuffer(pubkeys[0]));
+
+    const scripts = [];
+    scripts.push(Script.fromPubkey(pubkeys[0])); // P2PK
+    const pubkeyhash = hash160.digest(pubkeys[0]);
+    scripts.push(Script.fromPubkeyhash(pubkeyhash)); // P2PKH
+
+    if (pubkeys[0].length === 33) {
+      const p2wpkh = Script.fromProgram(0, pubkeyhash);
+      scripts.push(p2wpkh); // P2WPKH
+      const p2sh = Script.fromScripthash(p2wpkh.hash160()); // P2SH-P2WPKH
+      scripts.push(p2sh);
+    }
+
+    return scripts;
+  }
 }
 
 /*

lib/descriptor/type/multisig.js

@@ -14,13 +14,15 @@ const {MAX_SCRIPT_PUSH, MAX_MULTISIG_PUBKEYS} = consensus;
 const KeyProvider = require('../keyprovider');
 const Network = require('../../protocol/network');
 const assert = require('bsert');
+const Script = require('../../script/script');
 
 /**
  * MultisigDescriptor
  * Represents a multisig output script.
  * @see https://github.com/bitcoin/bips/blob/master/bip-0383.mediawiki
  * @property {String} type
  * @property {KeyProvider[]} keyProviders
+ * @property {String} scriptContext
  * @property {Number} threshold
  * @property {Boolean} isSorted - true if descriptor is sortedmulti
  * @property {Network} network
@@ -148,6 +150,7 @@ class MultisigDescriptor extends AbstractDescriptor {
     this.keyProviders = providers;
     this.isSorted = isSorted;
     this.network = Network.get(network);
+    this.scriptContext = context;
 
     return this;
   }
@@ -167,6 +170,36 @@ class MultisigDescriptor extends AbstractDescriptor {
   toStringExtra() {
     return this.threshold.toString();
   }
+
+  /**
+   * Get the scripts (helper function).
+   * @param {Buffer[]} pubkeys
+   * @returns {Script[]}
+   */
+
+  _getScripts(pubkeys) {
+    assert(Array.isArray(pubkeys) && pubkeys.length > 0);
+
+    for (const pubkey of pubkeys) {
+      assert(Buffer.isBuffer(pubkey));
+    }
+
+    const m = this.threshold;
+    const n = pubkeys.length;
+    const isWitness =  this.scriptContext === scriptContext.P2WSH;
+
+    return [Script.fromMultisig(m, n, pubkeys, this.isSorted, isWitness)];
+  }
+
+  /**
+   * Derive addresses from scripts.
+   * @param {Script[]} scripts
+   * @returns {Address[]}
+   */
+
+  getAddresses(scripts) {
+    throw new Error('Descriptor does not have a corresponding address');
+  }
 }
 
 /**

lib/descriptor/type/pk.js

@@ -12,12 +12,14 @@ const {isType, strip, checkChecksum, scriptContext, types} = common;
 const assert = require('bsert');
 const KeyProvider = require('../keyprovider');
 const Network = require('../../protocol/network');
+const Script = require('../../script/script');
 
 /**
  * PKDescriptor
  * Represents a P2PK output script.
  * @see https://github.com/bitcoin/bips/blob/master/bip-0381.mediawiki#pk
  * @property {String} type
+ * @property {String} scriptContext
  * @property {KeyProvider[]} keyProviders
  * @property {Network} network
  * @extends AbstractDescriptor
@@ -88,6 +90,7 @@ class PKDescriptor extends AbstractDescriptor {
 
     this.keyProviders = [provider];
     this.network = Network.get(network);
+    this.scriptContext = context;
 
     return this;
   }
@@ -103,6 +106,19 @@ class PKDescriptor extends AbstractDescriptor {
   static fromString(str, network, context = scriptContext.TOP) {
     return new this().fromString(str, network, context);
   }
+
+  /**
+   * Get the scripts (helper function).
+   * @param {Buffer[]} pubkeys
+   * @returns {Script[]}
+   */
+
+  _getScripts(pubkeys) {
+    assert(Array.isArray(pubkeys) && pubkeys.length === 1);
+    assert(Buffer.isBuffer(pubkeys[0]));
+
+    return [Script.fromPubkey(pubkeys[0])];
+  }
 }
 
 /*

lib/descriptor/type/pkh.js

@@ -12,12 +12,15 @@ const {isType, strip, checkChecksum, scriptContext, types} = common;
 const assert = require('bsert');
 const KeyProvider = require('../keyprovider');
 const Network = require('../../protocol/network');
+const hash160 = require('bcrypto/lib/hash160');
+const Script = require('../../script/script');
 
 /**
  * PKHDescriptor
  * Represents a P2PKH output script.
  * @see https://github.com/bitcoin/bips/blob/master/bip-0381.mediawiki#pkh
  * @property {String} type
+ * @property {String} scriptContext
  * @property {Network} network
  * @property {KeyProvider[]} keyProviders
  * @extends AbstractDescriptor
@@ -95,6 +98,7 @@ class PKHDescriptor extends AbstractDescriptor {
 
     this.keyProviders = [provider];
     this.network = Network.get(network);
+    this.scriptContext = context;
 
     return this;
   }
@@ -110,6 +114,20 @@ class PKHDescriptor extends AbstractDescriptor {
   static fromString(str, network, context = scriptContext.TOP) {
     return new this().fromString(str, network, context);
   }
+
+  /**
+   * Get the scripts (helper function).
+   * @param {Buffer[]} pubkeys
+   * @returns {Script[]}
+   */
+
+  _getScripts(pubkeys) {
+    assert(Array.isArray(pubkeys) && pubkeys.length === 1);
+    assert(Buffer.isBuffer(pubkeys[0]));
+
+    const pubkeyhash = hash160.digest(pubkeys[0]);
+    return [Script.fromPubkeyhash(pubkeyhash)];
+  }
 }
 
 /*

lib/descriptor/type/raw.js

@@ -18,6 +18,7 @@ const assert = require('bsert');
  * Represents the script represented by HEX in input.
  * @see https://github.com/bitcoin/bips/blob/master/bip-0385.mediawiki#raw
  * @property {String} type
+ * @property {String} scriptContext
  * @property {Script} script
  * @property {Network} network
  * @extends AbstractDescriptor
@@ -115,6 +116,15 @@ class RawDescriptor extends AbstractDescriptor {
   toStringExtra() {
     return this.script.toJSON();
   }
+
+  /**
+   * Get the scripts (helper function).
+   * @returns {Script[]}
+   */
+
+  _getScripts() {
+    return [this.script];
+  }
 }
 
 /*

lib/descriptor/type/sh.js

@@ -15,14 +15,15 @@ const WSHDescriptor = require('./wsh');
 const assert = require('bsert');
 const common = require('../common');
 const {isType, strip, getType, scriptContext, checkChecksum, types} = common;
-
 const Network = require('../../protocol/network');
+const Script = require('../../script/script');
 
 /**
  * SHDescriptor
  * Represents a P2SH output script.
  * @see https://github.com/bitcoin/bips/blob/master/bip-0381.mediawiki#sh
  * @property {String} type
+ * @property {String} scriptContext
  * @property {Descriptor[]} subdescriptors
  * @property {Network} network
  * @extends AbstractDescriptor
@@ -63,6 +64,7 @@ class SHDescriptor extends AbstractDescriptor {
     );
 
     const subdesc = options.subdescriptors[0];
+    subdesc.scriptContext = scriptContext.P2SH;
     const isValid = this.isValidSubdescriptor(subdesc.type);
 
     assert(isValid, `Can not have ${subdesc.type}() inside sh()`);
@@ -155,6 +157,21 @@ class SHDescriptor extends AbstractDescriptor {
 
     return validSubTypes.includes(type);
   }
+
+  /**
+   * Get the scripts (helper function).
+   * @param {Buffer[]} pubkeys
+   * @param {Script[]} subscripts
+   * @returns {Script[]}
+   */
+
+  _getScripts(pubkeys, subscripts) {
+    assert(Array.isArray(pubkeys) && pubkeys.length === 0);
+    assert(Array.isArray(subscripts) && subscripts.length === 1);
+    assert(subscripts[0] instanceof Script);
+
+    return [Script.fromScripthash(subscripts[0].hash160())];
+  }
 }
 
 /*