test sqlite3 interrupt

test_sqlite3_int.cc

#define _MULTI_THREADED

#include <sqlite3.h>
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>

int callback(void *, int, char **, char **);
void check(const char *str, int err);
void *threadfunc(void *parm);

// clang -O3 -lsqlite3 ./test_sqlite_int.cc && /usr/bin/time ./a.out
int main(void) {
  sqlite3 *db;
  sqlite3_stmt *res;

  int rc = sqlite3_open(":memory:", &db);
  if (rc != SQLITE_OK) {
    fprintf(stderr, "Cannot open database: %s\n", sqlite3_errmsg(db));
    sqlite3_close(db);
    return 1;
  }

  {
    rc = sqlite3_prepare_v2(db, "SELECT SQLITE_VERSION()", -1, &res, 0);
    if (rc != SQLITE_OK) {
      fprintf(stderr, "Failed to fetch data: %s\n", sqlite3_errmsg(db));
      sqlite3_close(db);
      return 1;
    }

    rc = sqlite3_step(res);
    if (rc == SQLITE_ROW) {
      printf("%s\n", sqlite3_column_text(res, 0));
    }

    sqlite3_finalize(res);
  }

  {
    // 2**26 = 67108864
    const char *sql =
      "WITH RECURSIVE"
      " fibo (curr, next) "
      "AS "
      "( SELECT 1,1"
      "  UNION ALL"
      "  SELECT next, curr+next FROM fibo"
      "  LIMIT  67108864 ) "
      "SELECT curr, next FROM fibo LIMIT 1 OFFSET 67108864-1";
    char *err_msg = 0;
    pthread_t t;

    check("pthread_create", pthread_create(&t, nullptr, threadfunc, db));

    rc = sqlite3_exec(db, sql, callback, 0, &err_msg);
    if (rc != SQLITE_OK) {
      fprintf(stderr, "Failed to select data\n");
      fprintf(stderr, "SQL error: %s\n", err_msg);

      sqlite3_free(err_msg);
      sqlite3_close(db);

      return 1;
    }

    pthread_join(t, nullptr);
  }

  sqlite3_close(db);

  return 0;
}

int callback(void *NotUsed, int argc, char **argv, char **azColName) {
  NotUsed = 0;

  for (int i = 0; i < argc; i++) {
    printf("%s = %s\n", azColName[i], argv[i] ? argv[i] : "NULL");
  }

  printf("\n");

  return 0;
}

void check(const char *str, int err) {
  if (err) {
    fprintf(stderr, "[%d] %s: err=%d\n", gettid(), str, err);
  }
}

void *threadfunc(void *parm) {
  printf("[%d] watcher: sleep 1\n", gettid());
  sleep(1);
  printf("[%d] watcher: slept 1\n", gettid());
  sqlite3_interrupt((sqlite3*)parm);
  printf("[%d] watcher: interrupted?!\n", gettid());
  return NULL;
}