context CHANGE basic context implementation
diff --git a/src/libyang.h b/src/libyang.h
index ca649c3..a023fbb 100644
--- a/src/libyang.h
+++ b/src/libyang.h
@@ -15,23 +15,257 @@
#ifndef LY_LIBYANG_H_
#define LY_LIBYANG_H_
+#include <stdint.h>
+
#ifdef __cplusplus
extern "C" {
#endif
/**
+ * @defgroup context Context
+ * @{
+ *
+ * Structures and functions to manipulate with the libyang "containers". The \em context concept allows callers
+ * to work in environments with different sets of YANG schemas. More detailed information can be found at
+ * @ref howtocontext page.
+ */
+
+/**
* @struct ly_ctx
* @brief libyang context handler.
*/
struct ly_ctx;
-
-#ifdef __cplusplus
-}
-#endif
+/**@} context */
#include "log.h"
#include "set.h"
#include "dict.h"
+#include "tree_schema.h"
+
+/**
+ * @ingroup context
+ * @{
+ */
+
+/**
+ * @defgroup contextoptions Context options
+ * @ingroup context
+ *
+ * Options to change context behavior.
+ * @{
+ */
+
+#define LY_CTX_ALLIMPLEMENTED 0x01 /**< All the imports of the schema being parsed are treated implemented. */
+#define LY_CTX_TRUSTED 0x02 /**< Handle the schema being parsed as trusted and skip its validation
+ tests. Note that while this option improves performance, it can
+ lead to an undefined behavior if the schema is not correct. */
+#define LY_CTX_NOYANGLIBRARY 0x04 /**< Do not internally implement ietf-yang-library module. The option
+ causes that function ly_ctx_info() does not work (returns NULL) until
+ the ietf-yang-library module is loaded manually. While any revision
+ of this schema can be loaded with this option, note that the only
+ revisions implemented by ly_ctx_info() are 2016-04-09 and 2018-01-17.
+ This option cannot be used with ly_ctx_new_yl*() functions. */
+#define LY_CTX_DISABLE_SEARCHDIRS 0x08 /**< Do not search for schemas in context's searchdirs neither in current
+ working directory. It is entirely skipped and the only way to get
+ schema data for imports or for ly_ctx_load_module() is to use the
+ callbacks provided by caller via ly_ctx_set_module_imp_clb() */
+#define LY_CTX_DISABLE_SEARCHDIR_CWD 0x10 /**< Do not automatically search for schemas in current working
+ directory, which is by default searched automatically (despite not
+ recursively). */
+#define LY_CTX_PREFER_SEARCHDIRS 0x20 /**< When searching for schema, prefer searchdirs instead of user callback. */
+/**@} contextoptions */
+
+/**
+ * @brief Create libyang context.
+ *
+ * Context is used to hold all information about schemas. Usually, the application is supposed
+ * to work with a single context in which libyang is holding all schemas (and other internal
+ * information) according to which the data trees will be processed and validated. So, the schema
+ * trees are tightly connected with the specific context and they are held by the context internally
+ * - caller does not need to keep pointers to the schemas returned by lys_parse(), context knows
+ * about them. The data trees created with lyd_parse() are still connected with the specific context,
+ * but they are not internally held by the context. The data tree just points and lean on some data
+ * held by the context (schema tree, string dictionary, etc.). Therefore, in case of data trees, caller
+ * is supposed to keep pointers returned by the lyd_parse() and manage the data tree on its own. This
+ * also affects the number of instances of both tree types. While you can have only one instance of
+ * specific schema connected with a single context, number of data tree instances is not connected.
+ *
+ * @param[in] search_dir Directory where libyang will search for the imported or included modules
+ * and submodules. If no such directory is available, NULL is accepted.
+ * @param[in] options Context options, see @ref contextoptions.
+ * @param[out] new_ctx Pointer to the created libyang context if LY_SUCCESS returned.
+ * @return LY_ERR return value.
+ */
+LY_ERR ly_ctx_new(const char *search_dir, int options, struct ly_ctx **new_ctx);
+
+/**
+ * @brief Add the search path into libyang context
+ *
+ * To reset search paths set in the context, use ly_ctx_unset_searchdirs() and then
+ * set search paths again.
+ *
+ * @param[in] ctx Context to be modified.
+ * @param[in] search_dir New search path to add to the current paths previously set in ctx.
+ * @return EXIT_SUCCESS, EXIT_FAILURE.
+ */
+int ly_ctx_set_searchdir(struct ly_ctx *ctx, const char *search_dir);
+
+/**
+ * @brief Clean the search path(s) from the libyang context
+ *
+ * @param[in] ctx Context to be modified.
+ * @param[in] index Index of the search path to be removed, use negative value to remove them all.
+ * Correct index value can be checked via ly_ctx_get_searchdirs().
+ * @return LY_ERR return value
+ */
+LY_ERR ly_ctx_unset_searchdirs(struct ly_ctx *ctx, int index);
+
+/**
+ * @brief Get the NULL-terminated list of the search paths in libyang context. Do not modify the result!
+ *
+ * @param[in] ctx Context to query.
+ * @return NULL-terminated list (array) of the search paths, NULL if no searchpath was set.
+ * Do not modify the provided data in any way!
+ */
+const char * const *ly_ctx_get_searchdirs(const struct ly_ctx *ctx);
+
+/**
+ * @brief Get the currently set context's options.
+ *
+ * @param[in] ctx Context to query.
+ * @return Combination of all the currently set context's options, see @ref contextoptions.
+ */
+int ly_ctx_get_options(struct ly_ctx *ctx);
+
+/**
+ * @brief Make context to stop searching for schemas (imported, included or requested via ly_ctx_load_module())
+ * in searchdirs set via ly_ctx_set_searchdir() functions. Searchdirs are still stored in the context, so by
+ * unsetting the option by ly_ctx_unset_disable_searchdirs() searching in all previously searchdirs is restored.
+ *
+ * The same effect is achieved by using #LY_CTX_DISABLE_SEARCHDIRS option when creating new context or parsing
+ * a specific schema.
+ *
+ * @param[in] ctx Context to be modified.
+ */
+void ly_ctx_set_disable_searchdirs(struct ly_ctx *ctx);
+
+/**
+ * @brief Reverse function to ly_ctx_set_disable_searchdirs().
+ *
+ * @param[in] ctx Context to be modified.
+ */
+void ly_ctx_unset_disable_searchdirs(struct ly_ctx *ctx);
+
+/**
+ * @brief Make context to stop implicitly searching for schemas (imported, included or requested via ly_ctx_load_module())
+ * in current working directory. This flag can be unset by ly_ctx_unset_disable_searchdir_cwd().
+ *
+ * The same effect is achieved by using #LY_CTX_DISABLE_SEARCHDIR_CWD option when creating new context or parsing
+ * a specific schema.
+ *
+ * @param[in] ctx Context to be modified.
+ */
+void ly_ctx_set_disable_searchdir_cwd(struct ly_ctx *ctx);
+
+/**
+ * @brief Reverse function to ly_ctx_set_disable_searchdir_cwd().
+ *
+ * @param[in] ctx Context to be modified.
+ */
+void ly_ctx_unset_disable_searchdir_cwd(struct ly_ctx *ctx);
+
+/**
+ * @brief Prefer context's searchdirs before the user callback (ly_module_imp_clb) provided via ly_ctx_set_module_imp_clb()).
+ *
+ * The same effect is achieved by using #LY_CTX_PREFER_SEARCHDIRS option when creating new context or parsing
+ * a specific schema.
+ *
+ * @param[in] ctx Context to be modified.
+ */
+void ly_ctx_set_prefer_searchdirs(struct ly_ctx *ctx);
+
+/**
+ * @brief Reverse function to ly_ctx_set_prefer_searchdirs().
+ *
+ * @param[in] ctx Context to be modified.
+ */
+void ly_ctx_unset_prefer_searchdirs(struct ly_ctx *ctx);
+
+/**
+ * @brief Make context to set all the imported modules to be implemented. By default,
+ * if the imported module is not used in leafref's path, augment or deviation, it is
+ * imported and its data tree is not taken into account.
+ *
+ * The same effect is achieved by using #LY_CTX_ALLIMPLEMENTED option when creating new context or parsing
+ * a specific schema.
+ *
+ * Note, that function does not make the currently loaded modules, it just change the
+ * schema parser behavior for the future parsing. This flag can be unset by ly_ctx_unset_allimplemented().
+ *
+ * @param[in] ctx Context to be modified.
+ */
+void ly_ctx_set_allimplemented(struct ly_ctx *ctx);
+
+/**
+ * @brief Reverse function to ly_ctx_set_allimplemented().
+ *
+ * @param[in] ctx Context to be modified.
+ */
+void ly_ctx_unset_allimplemented(struct ly_ctx *ctx);
+
+/**
+ * @brief Change the schema parser behavior when parsing new schemas forcing it to skip some of the schema
+ * validation checks to improve performance. Note that parsing invalid schemas this way may lead to an
+ * undefined behavior later, e.g. when working with data trees.
+ *
+ * The same effect is achieved by using #LY_CTX_TRUSTED option when creating new context or parsing
+ * a specific schema.
+ *
+ * This flag can be unset by ly_ctx_unset_trusted().
+ *
+ * @param[in] ctx Context to be modified.
+ */
+void ly_ctx_set_trusted(struct ly_ctx *ctx);
+
+/**
+ * @brief Reverse function to ly_ctx_set_trusted().
+ *
+ * @param[in] ctx Context to be modified.
+ */
+void ly_ctx_unset_trusted(struct ly_ctx *ctx);
+
+/**
+ * @brief Get current ID of the modules set. The value is available also
+ * as module-set-id in ly_ctx_info() result.
+ *
+ * @param[in] ctx Context to be examined.
+ * @return Numeric identifier of the current context's modules set.
+ */
+uint16_t ly_ctx_get_module_set_id(const struct ly_ctx *ctx);
+
+/**
+ * @brief Free all internal structures of the specified context.
+ *
+ * The function should be used before terminating the application to destroy
+ * and free all structures internally used by libyang. If the caller uses
+ * multiple contexts, the function should be called for each used context.
+ *
+ * All instance data are supposed to be freed before destroying the context.
+ * Data models are destroyed automatically as part of ly_ctx_destroy() call.
+ *
+ * @param[in] ctx libyang context to destroy
+ * @param[in] private_destructor Optional destructor function for private objects assigned
+ * to the nodes via lys_set_private(). If NULL, the private objects are not freed by libyang.
+ * Remember the differences between the structures derived from ::lys_node and always check
+ * ::lys_node#nodetype.
+ */
+void ly_ctx_destroy(struct ly_ctx *ctx, void (*private_destructor)(const struct lysc_node *node, void *priv));
+
+/** @} context */
+
+#ifdef __cplusplus
+}
+#endif
#endif /* LY_LIBYANG_H_ */