begin rework for js tests and hook examples

hook/examples/doubler/doubler.c

@@ -0,0 +1,72 @@
+//Authors: NeilH, RichardAH
+// (joke) test hook that doubles incoming XRP payments and sends it back
+// April 1st 2021: Added (unfair) coin flip
+
+#include <stdint.h>
+#include "../hookapi.h"
+
+int64_t hook(uint32_t reserved)
+{
+    
+    uint8_t hook_accid[20];
+    if (hook_account(SBUF(hook_accid)) < 0)
+        rollback(SBUF("Doubler: Could not fetch hook account id."), 1);
+
+    // next fetch the sfAccount field from the originating transaction
+    uint8_t account_field[20];
+    int32_t account_field_len = otxn_field(SBUF(account_field), sfAccount);
+
+    // compare the "From Account" (sfAccount) on the transaction with the account the hook is running on
+    int equal = 0; BUFFER_EQUAL(equal, hook_accid, account_field, 20);
+    if (equal)
+    {
+        accept(SBUF("Doubler: Outgoing transaction. Passing."), 2);
+        return 0;
+    }
+
+    uint8_t digest[96];
+    if (ledger_last_hash(digest, 32) != 32)
+        rollback(SBUF("Doubler: Failed to fetch last closed ledger."), 3);
+
+    uint8_t key[32]; // left as 0...0
+    state(digest + 32, 32, SBUF(key)); // if this load fails then we don't care, the hash is just 0
+    etxn_nonce(digest + 64, 32); // todo: if we enforce sfFirstLedgerSequence = +1 then this will be impossible to cheat
+
+    uint8_t hash[32];
+    if (util_sha512h(SBUF(hash), SBUF(digest)) != 32)
+        rollback(SBUF("Doubler: Could not compute digest for coin flip."), 4);
+
+    if (state_set(SBUF(hash), SBUF(key)) != 32)
+        rollback(SBUF("Doubler: Could not set state."), 5);
+
+    // first digit of lcl hash is our biased coin flip, you lose 60% of the time :P
+    if (hash[0] % 10 < 6)
+        accept(SBUF("Doubler: Tails, you lose. Om nom nom xrp."), 4);
+
+    // before we start calling hook-api functions we should tell the hook how many tx we intend to create
+    etxn_reserve(1); // we are going to emit 1 transaction
+
+    // fetch the sent Amount
+    // Amounts can be 384 bits or 64 bits. If the Amount is an XRP value it will be 64 bits.
+    unsigned char amount_buffer[48];
+    int64_t amount_len = otxn_field(SBUF(amount_buffer), sfAmount);
+    int64_t drops_to_send = AMOUNT_TO_DROPS(amount_buffer) * 2; // doubler pays back 2x received
+
+    if (amount_len != 8)
+        rollback(SBUF("Doubler: Rejecting incoming non-XRP transaction"), 5);
+
+    uint8_t tx[PREPARE_PAYMENT_SIMPLE_SIZE];
+
+    // we will use an XRP payment macro, this will populate the buffer with a serialized binary transaction
+    // Parameter list: ( buf_out, drops_amount, drops_fee, to_address, dest_tag, src_tag )
+    PREPARE_PAYMENT_SIMPLE(tx, drops_to_send, account_field, 0, 0);
+
+    // emit the transaction
+    uint8_t emithash[32];
+    emit(SBUF(emithash), SBUF(tx));
+
+    // accept and allow the original transaction through
+    accept(SBUF("Doubler: Heads, you won! Funds emitted!"), 0);
+    return 0;
+
+}

hook/examples/doubler/doubler.js

@@ -0,0 +1,35 @@
+const wasm = 'doubler.wasm'
+if (process.argv.length < 3)
+{
+    console.log("Usage: node doubler <account family seed>")
+    process.exit(1);
+}
+
+
+require('../../utils-tests.js').TestRig('ws://localhost:6005').then(t=>
+{
+    const secret  = process.argv[2];
+    const account = t.xrpljs.Wallet.fromSeed(secret)
+    t.feeSubmit(process.argv[2],
+    {
+        Account: account.classicAddress,
+        TransactionType: "SetHook",
+        Hooks: [
+            {
+                Hook: {
+                    CreateCode: t.wasm(wasm),
+                    HookApiVersion: 0,
+                    HookNamespace: "CAFECAFECAFECAFECAFECAFECAFECAFECAFECAFECAFECAFECAFECAFECAFECAFE",
+                    HookOn: "0000000000000000",
+                    Flags: t.hsfOVERRIDE
+                }
+            }
+        ]
+    }).then(x=>
+    {
+        t.assertTxnSuccess(x)
+        console.log(x);
+        process.exit(0);
+
+    }).catch(t.err);
+}).catch(e=>console.log(e));

hook/examples/doubler/makefile

@@ -0,0 +1,4 @@
+all:
+	wasmcc doubler.c -o doubler.wasm -O2 -Wl,--allow-undefined -I../
+	hook-cleaner doubler.wasm
+

hook/examples/doubler/pay.js

@@ -0,0 +1,19 @@
+if (process.argv.length < 5)
+{
+    console.log("Usage: node pay <source family seed> <amount xrp> <destination account>")
+    process.exit(1)
+}
+const secret  = process.argv[2];
+const amount = BigInt(process.argv[3]) * 1000000n
+const dest = process.argv[4];
+
+require('../utils-tests.js').TestRig('ws://localhost:6005').then(t=>
+{
+    t.pay(secret, amount, dest).then(x=>
+    {
+        console.log(x);
+        process.exit(0);
+    });
+});
+
+