evmc/examples/capi.c

#include <evmc/evmc.h>

#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "examplevm/examplevm.h"


struct evmc_uint256be balance(struct evmc_context* context, const struct evmc_address* address)
{
    struct evmc_uint256be ret = {.bytes = {1, 2, 3, 4}};
    return ret;
}

struct evmc_address address(struct evmc_context* context)
{
    struct evmc_address ret = {.bytes = {1, 2, 3, 4}};
    return ret;
}

static void print_address(const struct evmc_address* address)
{
    int i = 0;
    for (i = 0; i < sizeof(address->bytes); ++i)
        printf("%x", address->bytes[i] & 0xff);
}

static int account_exists(struct evmc_context* context, const struct evmc_address* address)
{
    printf("EVM-C: EXISTS @");
    print_address(address);
    printf("\n");
    return 0;
}

static void get_storage(struct evmc_uint256be* result,
                        struct evmc_context* context,
                        const struct evmc_address* address,
                        const struct evmc_uint256be* key)
{
    printf("EVM-C: SLOAD @");
    print_address(address);
    printf("\n");
}

static void set_storage(struct evmc_context* context,
                        const struct evmc_address* address,
                        const struct evmc_uint256be* key,
                        const struct evmc_uint256be* value)
{
    printf("EVM-C: SSTORE @");
    print_address(address);
    printf("\n");
}

static void get_balance(struct evmc_uint256be* result,
                        struct evmc_context* context,
                        const struct evmc_address* address)
{
    printf("EVM-C: BALANCE @");
    print_address(address);
    printf("\n");
    *result = balance(context, address);
}

static size_t get_code_size(struct evmc_context* context, const struct evmc_address* address)
{
    printf("EVM-C: CODESIZE @");
    print_address(address);
    printf("\n");
    return 0;
}

static size_t copy_code(struct evmc_context* context,
                        const struct evmc_address* address,
                        size_t code_offset,
                        uint8_t* buffer_data,
                        size_t buffer_size)
{
    printf("EVM-C: COPYCODE @");
    print_address(address);
    printf("\n");
    return 0;
}

static void selfdestruct(struct evmc_context* context,
                         const struct evmc_address* address,
                         const struct evmc_address* beneficiary)
{
    printf("EVM-C: SELFDESTRUCT ");
    print_address(address);
    printf(" -> ");
    print_address(beneficiary);
    printf("\n");
}

static void call(struct evmc_result* result,
                 struct evmc_context* context,
                 const struct evmc_message* msg)
{
    printf("EVM-C: CALL (depth: %d)\n", msg->depth);
    result->status_code = EVMC_FAILURE;
}

static void get_tx_context(struct evmc_tx_context* result, struct evmc_context* context) {}

static void get_block_hash(struct evmc_uint256be* result,
                           struct evmc_context* context,
                           int64_t number)
{}

/// EVM log callback.
///
/// @note The `evm_log` name is used to avoid conflict with `log()` C function.
static void evm_log(struct evmc_context* context,
                    const struct evmc_address* address,
                    const uint8_t* data,
                    size_t data_size,
                    const struct evmc_uint256be topics[],
                    size_t topics_count)
{
    printf("EVM-C: LOG%d\n", (int)topics_count);
}

static const struct evmc_context_fn_table ctx_fn_table = {
    account_exists, get_storage, set_storage,    get_balance,    get_code_size, copy_code,
    selfdestruct,   call,        get_tx_context, get_block_hash, evm_log,
};

/// Example how the API is supposed to be used.
int main(int argc, char* argv[])
{
    struct evmc_instance* jit = evmc_create_examplevm();
    if (jit->abi_version != EVMC_ABI_VERSION)
        return 1;  // Incompatible ABI version.

    uint8_t const code[] = "Place some EVM bytecode here";
    const size_t code_size = sizeof(code);
    struct evmc_uint256be code_hash = {.bytes = {1, 2, 3}};
    uint8_t const input[] = "Hello World!";
    struct evmc_uint256be value = {{1, 0}};
    struct evmc_address addr = {{0, 1, 2}};
    int64_t gas = 200000;

    struct evmc_context ctx = {&ctx_fn_table};

    struct evmc_message msg = {addr, addr, value, input, sizeof(input), code_hash, gas, 0};

    struct evmc_result result = jit->execute(jit, &ctx, EVMC_HOMESTEAD, &msg, code, code_size);

    printf("Execution result:\n");
    if (result.status_code != EVMC_SUCCESS)
    {
        printf("  EVM execution failure: %d\n", result.status_code);
    }
    else
    {
        printf("  Gas used: %" PRId64 "\n", gas - result.gas_left);
        printf("  Gas left: %" PRId64 "\n", result.gas_left);
        printf("  Output size: %zd\n", result.output_size);

        printf("  Output: ");
        size_t i = 0;
        for (i = 0; i < result.output_size; i++)
            printf("%02x ", result.output_data[i]);
        printf("\n");
    }

    if (result.release)
        result.release(&result);
    jit->destroy(jit);

    return 0;
}