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 * notice, this list of conditions and the following disclaimer.
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 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
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#include "test/core/security/oauth2_utils.h"

#include <string.h>

#include <grpc/grpc.h>
#include <grpc/grpc_security.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/slice.h>
#include <grpc/support/sync.h>

#include "src/core/lib/security/credentials.h"

typedef struct {
  gpr_mu *mu;
  grpc_pollset *pollset;
  int is_done;
  char *token;
} oauth2_request;

static void on_oauth2_response(grpc_exec_ctx *exec_ctx, void *user_data,
                               grpc_credentials_md *md_elems, size_t num_md,
                               grpc_credentials_status status) {
  oauth2_request *request = user_data;
  char *token = NULL;
  gpr_slice token_slice;
  if (status == GRPC_CREDENTIALS_ERROR) {
    gpr_log(GPR_ERROR, "Fetching token failed.");
  } else {
    GPR_ASSERT(num_md == 1);
    token_slice = md_elems[0].value;
    token = gpr_malloc(GPR_SLICE_LENGTH(token_slice) + 1);
    memcpy(token, GPR_SLICE_START_PTR(token_slice),
           GPR_SLICE_LENGTH(token_slice));
    token[GPR_SLICE_LENGTH(token_slice)] = '\0';
  }
  gpr_mu_lock(request->mu);
  request->is_done = 1;
  request->token = token;
  grpc_pollset_kick(request->pollset, NULL);
  gpr_mu_unlock(request->mu);
}

static void do_nothing(grpc_exec_ctx *exec_ctx, void *unused, bool success) {}

char *grpc_test_fetch_oauth2_token_with_credentials(
    grpc_call_credentials *creds) {
  oauth2_request request;
  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
  grpc_closure do_nothing_closure;
  grpc_auth_metadata_context null_ctx = {"", "", NULL, NULL};

  request.pollset = gpr_malloc(grpc_pollset_size());
  grpc_pollset_init(request.pollset, &request.mu);
  request.is_done = 0;

  grpc_closure_init(&do_nothing_closure, do_nothing, NULL);

  grpc_call_credentials_get_request_metadata(&exec_ctx, creds, request.pollset,
                                             null_ctx, on_oauth2_response,
                                             &request);

  grpc_exec_ctx_finish(&exec_ctx);

  gpr_mu_lock(request.mu);
  while (!request.is_done) {
    grpc_pollset_worker *worker = NULL;
    grpc_pollset_work(&exec_ctx, request.pollset, &worker,
                      gpr_now(GPR_CLOCK_MONOTONIC),
                      gpr_inf_future(GPR_CLOCK_MONOTONIC));
  }
  gpr_mu_unlock(request.mu);

  grpc_pollset_shutdown(&exec_ctx, request.pollset, &do_nothing_closure);
  grpc_exec_ctx_finish(&exec_ctx);
  grpc_pollset_destroy(request.pollset);
  gpr_free(request.pollset);
  return request.token;
}