prepare Hook API

[tequdev]

High Level Overview of Change

require

• Hook API Refactor3: Consolidate the Hook API definitions from Enum.h and ApplyHook.h into a single file. #622

Context of Change

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• [x ] New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (non-breaking change that only restructures code)
• Tests (you added tests for code that already exists, or your new feature included in this PR)
• Documentation update
• Chore (no impact to binary, e.g. .gitignore, formatting, dropping support for older tooling)
• Release

API Impact

• Public API: New feature (new methods and/or new fields)
• Public API: Breaking change (in general, breaking changes should only impact the next api_version)
• libxrpl change (any change that may affect libxrpl or dependents of libxrpl)
• Peer protocol change (must be backward compatible or bump the peer protocol version)

[tequdev]

#include "hookapi.h"

extern int64_t prepare(uint32_t write_ptr, uint32_t write_len,
                       uint32_t read_ptr, uint32_t read_len);

uint8_t txn[1024] = {0x12, 0x00, ttACCOUNT_SET};
uint8_t txn_out[1024];

int64_t hook(uint32_t reserved) {
  etxn_reserve(1);

  uint32_t txn_out_len = prepare(SBUF(txn_out), txn, 3);

  ASSERT(txn_out_len > 0);

  uint8_t hash[32];
  ASSERT(emit(SBUF(hash), txn_out, txn_out_len) > 0);

  _g(1, 1);
  accept(SBUF("success"), __LINE__);
  return 0;
}

[RichardAH]

are you intending to change the workflow in this commit?

[tequdev]

This change itself was actually implemented in this prerequisite PR.

It's been updated to generate the extern.h based on hookapi.macro and then apply clang-format.

#622