Git fix: Re-add meta.js

src/js/meta.js

@@ -0,0 +1,108 @@
+var extend = require('extend');
+var UInt160 = require('./uint160').UInt160;
+var Amount = require('./amount').Amount;
+
+/**
+ * Meta data processing facility.
+ */
+var Meta = function (raw_data)
+{
+  this.nodes = [];
+
+  for (var i = 0, l = raw_data.AffectedNodes.length; i < l; i++) {
+    var an = raw_data.AffectedNodes[i],
+        result = {};
+
+    ["CreatedNode", "ModifiedNode", "DeletedNode"].forEach(function (x) {
+      if (an[x]) result.diffType = x;
+    });
+
+    if (!result.diffType) return null;
+
+    an = an[result.diffType];
+
+    result.entryType = an.LedgerEntryType;
+    result.ledgerIndex = an.LedgerIndex;
+
+    result.fields = extend({}, an.PreviousFields, an.NewFields, an.FinalFields);
+    result.fieldsPrev = an.PreviousFields || {};
+    result.fieldsNew = an.NewFields || {};
+    result.fieldsFinal = an.FinalFields || {};
+
+    this.nodes.push(result);
+  }
+};
+
+/**
+ * Execute a function on each affected node.
+ *
+ * The callback is passed two parameters. The first is a node object which looks
+ * like this:
+ *
+ *   {
+ *     // Type of diff, e.g. CreatedNode, ModifiedNode
+ *     diffType: 'CreatedNode'
+ *
+ *     // Type of node affected, e.g. RippleState, AccountRoot
+ *     entryType: 'RippleState',
+ *
+ *     // Index of the ledger this change occurred in
+ *     ledgerIndex: '01AB01AB...',
+ *
+ *     // Contains all fields with later versions taking precedence
+ *     //
+ *     // This is a shorthand for doing things like checking which account
+ *     // this affected without having to check the diffType.
+ *     fields: {...},
+ *
+ *     // Old fields (before the change)
+ *     fieldsPrev: {...},
+ *
+ *     // New fields (that have been added)
+ *     fieldsNew: {...},
+ *
+ *     // Changed fields
+ *     fieldsFinal: {...}
+ *   }
+ *
+ * The second parameter to the callback is the index of the node in the metadata
+ * (first entry is index 0).
+ */
+Meta.prototype.each = function (fn)
+{
+  for (var i = 0, l = this.nodes.length; i < l; i++) {
+    fn(this.nodes[i], i);
+  }
+};
+
+var amountFieldsAffectingIssuer = [
+  "LowLimit", "HighLimit", "TakerPays", "TakerGets"
+];
+Meta.prototype.getAffectedAccounts = function ()
+{
+  var accounts = [];
+
+  // This code should match the behavior of the C++ method:
+  // TransactionMetaSet::getAffectedAccounts
+  this.each(function (an) {
+    var fields = (an.diffType === "CreatedNode") ? an.fieldsNew : an.fieldsFinal;
+
+    for (var i in fields) {
+      var field = fields[i];
+
+      if ("string" === typeof field && UInt160.is_valid(field)) {
+        accounts.push(field);
+      } else if (amountFieldsAffectingIssuer.indexOf(i) !== -1) {
+        var amount = Amount.from_json(field);
+        var issuer = amount.issuer();
+        if (issuer.is_valid() && !issuer.is_zero()) {
+          accounts.push(issuer.to_json());
+        }
+      }
+    }
+  });
+
+  return accounts;
+};
+
+exports.Meta = Meta;