s/contract/program/

web3.js/src/system-program.js

@@ -0,0 +1,108 @@
+// @flow
+
+import assert from 'assert';
+
+import {Transaction} from './transaction';
+import type {PublicKey} from './account';
+
+/**
+ * Factory class for transactions to interact with the System program
+ */
+export class SystemProgram {
+  /**
+   * Public key that identifies the System program
+   */
+  static get programId(): PublicKey {
+    return '11111111111111111111111111111111';
+  }
+
+  /**
+   * Generate a Transaction that creates a new account
+   */
+  static createAccount(
+    from: PublicKey,
+    newAccount: PublicKey,
+    tokens: number,
+    space: number,
+    programId: ?PublicKey
+  ): Transaction {
+    const userdata = Buffer.alloc(4 + 8 + 8 + 1 + 32);
+    let pos = 0;
+
+    userdata.writeUInt32LE(0, pos); // Create Account instruction
+    pos += 4;
+
+    userdata.writeUInt32LE(tokens, pos); // tokens as i64
+    pos += 8;
+
+    userdata.writeUInt32LE(space, pos); // space as u64
+    pos += 8;
+
+    if (programId) {
+      userdata.writeUInt8(1, pos); // 'Some'
+      pos += 1;
+
+      const programIdBytes = Transaction.serializePublicKey(programId);
+      programIdBytes.copy(userdata, pos);
+      pos += 32;
+    } else {
+      userdata.writeUInt8(0, pos); // 'None'
+      pos += 1;
+    }
+
+    assert(pos <= userdata.length);
+
+    return new Transaction({
+      fee: 0,
+      keys: [from, newAccount],
+      programId: SystemProgram.programId,
+      userdata,
+    });
+  }
+
+  /**
+   * Generate a Transaction that moves tokens from one account to another
+   */
+  static move(from: PublicKey, to: PublicKey, amount: number): Transaction {
+    const userdata = Buffer.alloc(4 + 8);
+    let pos = 0;
+    userdata.writeUInt32LE(2, pos); // Move instruction
+    pos += 4;
+
+    userdata.writeUInt32LE(amount, pos); // amount as u64
+    pos += 8;
+
+    assert(pos === userdata.length);
+
+    return new Transaction({
+      fee: 0,
+      keys: [from, to],
+      programId: SystemProgram.programId,
+      userdata,
+    });
+  }
+
+  /**
+   * Generate a Transaction that assigns an account to a program
+   */
+  static assign(from: PublicKey, programId: PublicKey): Transaction {
+    const userdata = Buffer.alloc(4 + 32);
+    let pos = 0;
+
+    userdata.writeUInt32LE(1, pos); // Assign instruction
+    pos += 4;
+
+    const programIdBytes = Transaction.serializePublicKey(programId);
+    programIdBytes.copy(userdata, pos);
+    pos += programIdBytes.length;
+
+    assert(pos === userdata.length);
+
+    return new Transaction({
+      fee: 0,
+      keys: [from],
+      programId: SystemProgram.programId,
+      userdata,
+    });
+  }
+}