nix-super/src/libexpr/nix_api_expr.h

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#ifndef NIX_API_EXPR_H
#define NIX_API_EXPR_H
/** @file
* @brief Main entry for the libexpr C bindings
*/
#include "nix_api_store.h"
#include "nix_api_util.h"
#ifdef __cplusplus
extern "C" {
#endif
// cffi start
// Type definitions
/**
* @brief Represents a nix evaluator state.
*
* Multiple can be created for multi-threaded
* operation.
*/
typedef struct State State; // nix::EvalState
/**
* @brief Represents a nix value.
*
* Owned by the GC.
*/
typedef void Value; // nix::Value
// Function prototypes
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/**
* @brief Initializes the Nix expression evaluator.
*
* This function should be called before creating a State.
* This function can be called multiple times.
*
* @param[out] context Optional, stores error information
* @return NIX_OK if the initialization was successful, an error code otherwise.
*/
nix_err nix_libexpr_init(nix_c_context *context);
/**
* @brief Parses and evaluates a Nix expression from a string.
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*
* @param[out] context Optional, stores error information
* @param[in] state The state of the evaluation.
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* @param[in] expr The Nix expression to parse.
* @param[in] path The file path to associate with the expression.
* @param[out] value The result of the evaluation. You should allocate this
* yourself.
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* @return NIX_OK if the evaluation was successful, an error code otherwise.
*/
nix_err nix_expr_eval_from_string(nix_c_context *context, State *state,
const char *expr, const char *path,
Value *value);
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/**
* @brief Calls a Nix function with an argument.
*
* @param[out] context Optional, stores error information
* @param[in] state The state of the evaluation.
* @param[in] fn The Nix function to call.
* @param[in] arg The argument to pass to the function.
* @param[out] value The result of the function call.
* @return NIX_OK if the function call was successful, an error code otherwise.
*/
nix_err nix_value_call(nix_c_context *context, State *state, Value *fn,
Value *arg, Value *value);
/**
* @brief Forces the evaluation of a Nix value.
*
* @param[out] context Optional, stores error information
* @param[in] state The state of the evaluation.
* @param[in,out] value The Nix value to force.
* @return NIX_OK if the force operation was successful, an error code
* otherwise.
*/
nix_err nix_value_force(nix_c_context *context, State *state, Value *value);
/**
* @brief Forces the deep evaluation of a Nix value.
*
* @param[out] context Optional, stores error information
* @param[in] state The state of the evaluation.
* @param[in,out] value The Nix value to force.
* @return NIX_OK if the deep force operation was successful, an error code
* otherwise.
*/
nix_err nix_value_force_deep(nix_c_context *context, State *state,
Value *value);
/**
* @brief Creates a new Nix state.
*
* @param[out] context Optional, stores error information
* @param[in] searchPath The NIX_PATH.
* @param[in] store The Nix store to use.
* @return A new Nix state or NULL on failure.
*/
State *nix_state_create(nix_c_context *context, const char **searchPath,
Store *store);
/**
* @brief Frees a Nix state.
*
* Does not fail.
*
* @param[in] state The state to free.
*/
void nix_state_free(State *state);
/**
* @brief Increase the GC refcount.
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*
* The nix C api keeps alive objects by refcounting.
* When you're done with a refcounted pointer, call nix_gc_decref.
*
* Does not fail
*
* @param[in] object The object to keep alive
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*/
void nix_gc_incref(const void *);
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/**
* @brief Decrease the GC refcount
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*
* @param[in] object The object to stop referencing
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*/
void nix_gc_decref(const void *);
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/**
* @brief Register a callback that gets called when the object is garbage
* collected.
* @note objects can only have a single finalizer. This function overwrites
* silently.
* @param[in] obj the object to watch
* @param[in] cd the data to pass to the finalizer
* @param[in] finalizer the callback function, called with obj and cd
*/
void nix_gc_register_finalizer(void *obj, void *cd,
void (*finalizer)(void *obj, void *cd));
// cffi end
#ifdef __cplusplus
}
#endif
#endif // NIX_API_EXPR_H