C API: Add nix_clear_err

This commit is contained in:
Robert Hensing 2024-06-14 16:30:34 +02:00
parent afdd12be5e
commit 2dc7598779
3 changed files with 35 additions and 3 deletions

View file

@ -57,6 +57,12 @@ nix_err nix_set_err_msg(nix_c_context * context, nix_err err, const char * msg)
return err;
}
void nix_clear_err(nix_c_context * context)
{
if (context)
context->last_err_code = NIX_OK;
}
const char * nix_version_get()
{
return PACKAGE_VERSION;

View file

@ -221,7 +221,9 @@ const char * nix_version_get();
* @param[out] n optional: a pointer to an unsigned int that is set to the
* length of the error.
* @return nullptr if no error message was ever set,
* a borrowed pointer to the error message otherwise.
* a borrowed pointer to the error message otherwise, which is valid
* until the next call to a Nix function, or until the context is
* destroyed.
*/
const char * nix_err_msg(nix_c_context * context, const nix_c_context * ctx, unsigned int * n);
@ -282,13 +284,34 @@ nix_err nix_err_code(const nix_c_context * read_context);
*
* All other use is internal to the API.
*
* @param context context to write the error message to, or NULL
* @param context context to write the error message to, required unless C++ exceptions are supported
* @param err The error code to set and return
* @param msg The error message to set.
* @param msg The error message to set. This string is copied.
* @returns the error code set
*/
nix_err nix_set_err_msg(nix_c_context * context, nix_err err, const char * msg);
/**
* @brief Clear the error message from a nix context.
*
* This is performed implicitly by all functions that accept a context, so
* this won't be necessary in most cases.
* However, if you want to clear the error message without calling another
* function, you can use this.
*
* Example use case: a higher order function that helps with error handling,
* to make it more robust in the following scenario:
*
* 1. A previous call failed, and the error was caught and handled.
* 2. The context is reused with our error handling helper function.
* 3. The callback passed to the helper function doesn't actually make a call to
* a Nix function.
* 4. The handled error is raised again, from an unrelated call.
*
* This failure can be avoided by clearing the error message after handling it.
*/
void nix_clear_err(nix_c_context * context);
/**
* @}
*/

View file

@ -31,6 +31,9 @@ TEST_F(nix_api_util_context, nix_context_error)
}
ASSERT_EQ(ctx->last_err_code, NIX_ERR_UNKNOWN);
ASSERT_EQ(*ctx->last_err, err_msg_ref);
nix_clear_err(ctx);
ASSERT_EQ(ctx->last_err_code, NIX_OK);
}
TEST_F(nix_api_util_context, nix_set_err_msg)