diff --git a/include/crm/common/output.h b/include/crm/common/output.h index f31b78430f..a7fac89d80 100644 --- a/include/crm/common/output.h +++ b/include/crm/common/output.h @@ -1,513 +1,514 @@ /* * Copyright 2019 the Pacemaker project contributors * * The version control history for this file may have further details. * * This source code is licensed under the GNU Lesser General Public License * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY. */ #ifndef CRM_OUTPUT__H # define CRM_OUTPUT__H #ifdef __cplusplus extern "C" { #endif /** * \file * \brief Formatted output for pacemaker tools */ +# include # include # include # include # include # define PCMK__API_VERSION "1.0" /* Add to the long_options block in each tool to get the formatted output * command line options added. Then call pcmk__parse_output_args to handle * them. */ # define PCMK__OUTPUT_OPTIONS(fmts) \ { "output-as", required_argument, NULL, 0, \ "Specify the format for output, one of: " fmts \ }, \ { "output-to", required_argument, NULL, 0, \ "Specify the destination for formatted output, \"-\" for stdout or a filename" \ } typedef struct pcmk__output_s pcmk__output_t; /*! * \internal * \brief The type of a function that creates a ::pcmk__output_t. * * Instances of this type are passed to pcmk__register_format(), stored in an * internal data structure, and later accessed by pcmk__output_new(). For * examples, see pcmk__mk_xml_output() and pcmk__mk_text_output(). * * \param[in] argv The list of command line arguments. */ typedef pcmk__output_t * (*pcmk__output_factory_t)(char **argv); /*! * \internal * \brief The type of a custom message formatting function. * * These functions are defined by various libraries to support formatting of * types aside from the basic types provided by a ::pcmk__output_t. * * The meaning of the return value will be different for each message. * In general, however, 0 should be returned on success and a positive value * on error. * * \note These functions must not call va_start or va_end - that is done * automatically before the custom formatting function is called. */ typedef int (*pcmk__message_fn_t)(pcmk__output_t *out, va_list args); /*! * \internal * \brief Internal type for tracking custom messages. * * Each library can register functions that format custom message types. These * are commonly used to handle some library-specific type. Registration is * done by first defining a table of ::pcmk__message_entry_t structures and * then passing that table to pcmk__register_messages(). Separate handlers * can be defined for the same message, but for different formats (xml vs. * text). Unknown formats will be ignored. */ typedef struct pcmk__message_entry_s { /*! * \brief The message to be handled. * * This must be the same ID that is passed to the message function of * a ::pcmk__output_t. Unknown message IDs will be ignored. */ const char *message_id; /*! * \brief The format type this handler is for. * * This name must match the fmt_name of the currently active formatter in * order for the registered function to be called. It is valid to have * multiple entries for the same message_id but with different fmt_name * values. */ const char *fmt_name; /*! * \brief The function to be called for message_id given a match on * fmt_name. See comments on ::pcmk__message_fn_t. */ pcmk__message_fn_t fn; } pcmk__message_entry_t; /* Basic formatters everything supports. This block needs to be updated every * time a new base formatter is added. */ pcmk__output_t *pcmk__mk_text_output(char **argv); pcmk__output_t *pcmk__mk_xml_output(char **argv); /*! * \brief This structure contains everything that makes up a single output * formatter. * * Instances of this structure may be created by calling pcmk__output_new() * with the name of the desired formatter. They should later be freed with * pcmk__output_free(). */ struct pcmk__output_s { /*! * \brief The name of this output formatter. */ char *fmt_name; /*! * \brief A copy of the request that generated this output. * * In the case of command line usage, this would be the command line * arguments. For other use cases, it could be different. */ char *request; /*! * \brief Does this formatter support a special quiet mode? * * In this mode, most output can be supressed but some information is still * displayed to an interactive user. In general, machine-readable output * formats will not support this while user-oriented formats will. */ bool supports_quiet; /*! * \brief Where output should be written. * * This could be a file handle, or stdout or stderr. This is really only * useful internally. */ FILE *dest; /*! * \brief Custom messages that are currently registered on this formatter. * * Keys are the string message IDs, values are ::pcmk__message_fn_t function * pointers. */ GHashTable *messages; /*! * \brief Implementation-specific private data. * * Each individual formatter may have some private data useful in its * implementation. This points to that data. Callers should not rely on * its contents or structure. */ void *priv; /*! * \internal * \brief Take whatever actions are necessary to prepare out for use. This is * called by pcmk__output_new(). End users should not need to call this. * * \note For formatted output implementers - This function should be written in * such a way that it can be called repeatedly on an already initialized * object without causing problems, or on a previously finished object * without crashing. * * \param[in,out] out The output functions structure. * * \return true on success, false on error. */ bool (*init) (pcmk__output_t *out); /*! * \internal * \brief Free the private formatter-specific data. * * This is called from pcmk__output_free() and does not typically need to be * called directly. * * \param[in,out] out The output functions structure. */ void (*free_priv)(pcmk__output_t *out); /*! * \internal * \brief Take whatever actions are necessary to end formatted output. * * This could include flushing output to a file, but does not include freeing * anything. Note that pcmk__output_free() will automatically call this * function, so there is typically no need to do so manually. * * \note For formatted output implementers - This function should be written in * such a way that it can be called repeatedly on a previously finished * object without crashing. * * \param[in,out] out The output functions structure. * \param[in] exit_status The exit value of the whole program. */ void (*finish) (pcmk__output_t *out, crm_exit_t exit_status); /*! * \internal * \brief Finalize output and then immediately set back up to start a new set * of output. * * This is conceptually the same as calling finish and then init, though in * practice more be happening behind the scenes. * * \note This function differs from finish in that no exit_status is added. * The idea is that the program is not shutting down, so there is not * yet a final exit code. Call finish on the last time through if this * is needed. * * \param[in,out] out The output functions structure. */ void (*reset) (pcmk__output_t *out); /*! * \internal * \brief Register a custom message. * * \param[in,out] out The output functions structure. * \param[in] message_id The name of the message to register. This name * will be used as the message_id parameter to the * message function in order to call the custom * format function. * \param[in] fn The custom format function to call for message_id. */ void (*register_message) (pcmk__output_t *out, const char *message_id, pcmk__message_fn_t fn); /*! * \internal * \brief Call a previously registered custom message. * * \param[in,out] out The output functions structure. * \param[in] message_id The name of the message to call. This name must * be the same as the message_id parameter of some * previous call to register_message. * \param[in] ... Arguments to be passed to the registered function. * * \return 0 if a function was registered for the message, that function was * called, and returned successfully. A negative value is returned if * no function was registered. A positive value is returned if the * function was called but encountered an error. */ int (*message) (pcmk__output_t *out, const char *message_id, ...); /*! * \internal * \brief Format the output of a completed subprocess. * * \param[in,out] out The output functions structure. * \param[in] exit_status The exit value of the subprocess. * \param[in] proc_stdout stdout from the completed subprocess. * \param[in] proc_stderr stderr from the completed subprocess. */ void (*subprocess_output) (pcmk__output_t *out, int exit_status, const char *proc_stdout, const char *proc_stderr); /*! * \internal * \brief Format an informational message that should be shown to * to an interactive user. Not all formatters will do this. * * \note A newline will automatically be added to the end of the format * string, so callers should not include a newline. * * \param[in,out] out The output functions structure. * \param[in] buf The message to be printed. * \param[in] ... Arguments to be formatted. */ void (*info) (pcmk__output_t *out, const char *format, ...) G_GNUC_PRINTF(2, 3); /*! * \internal * \brief Format already formatted XML. * * \param[in,out] out The output functions structure. * \param[in] name A name to associate with the XML. * \param[in] buf The XML in a string. */ void (*output_xml) (pcmk__output_t *out, const char *name, const char *buf); /*! * \internal * \brief Start a new list of items. * * \note For text output, this corresponds to another level of indentation. For * XML output, this corresponds to wrapping any following output in another * layer of tags. * * \note If singular_noun and plural_noun are non-NULL, calling end_list will * result in a summary being added. * * \param[in,out] out The output functions structure. * \param[in] name A descriptive, user-facing name for this list. * \param[in] singular_noun When outputting the summary for a list with * one item, the noun to use. * \param[in] plural_noun When outputting the summary for a list with * more than one item, the noun to use. */ void (*begin_list) (pcmk__output_t *out, const char *name, const char *singular_noun, const char *plural_noun); /*! * \internal * \brief Format a single item in a list. * * \param[in,out] out The output functions structure. * \param[in] name A name to associate with this item. * \param[in] content The item to be formatted. */ void (*list_item) (pcmk__output_t *out, const char *name, const char *content); /*! * \internal * \brief Conclude a list. * * \note If begin_list was called with non-NULL for both the singular_noun * and plural_noun arguments, this function will output a summary. * Otherwise, no summary will be added. * * \param[in,out] out The output functions structure. */ void (*end_list) (pcmk__output_t *out); }; /*! * \internal * \brief Call a formatting function for a previously registered message. * * \note This function is for implementing custom formatters. It should not * be called directly. Instead, call out->message. * * \param[in,out] out The output functions structure. * \param[in] message_id The message to be handled. Unknown messages * will be ignored. * \param[in] ... Arguments to be passed to the registered function. */ int pcmk__call_message(pcmk__output_t *out, const char *message_id, ...); /*! * \internal * \brief Free a ::pcmk__output_t structure that was previously created by * pcmk__output_new(). This will first call the finish function. * * \note While the create and finish functions are designed in such a way that * they can be called repeatedly, this function will completely free the * memory of the object. Once this function has been called, producing * more output requires starting over from pcmk__output_new(). * * \param[in,out] out The output structure. * \param[in] exit_status The exit value of the whole program. */ void pcmk__output_free(pcmk__output_t *out, crm_exit_t exit_status); /*! * \internal * \brief Create a new ::pcmk__output_t structure. * * \param[in,out] out The destination of the new ::pcmk__output_t. * \param[in] fmt_name How should output be formatted? * \param[in] filename Where should formatted output be written to? This * can be a filename (which will be overwritten if it * already exists), or NULL or "-" for stdout. For no * output, pass a filename of "/dev/null". * \param[in] argv The list of command line arguments. * * \return 0 on success or an error code on error. */ int pcmk__output_new(pcmk__output_t **out, const char *fmt_name, const char *filename, char **argv); /*! * \internal * \brief Process formatted output related command line options. This should * be called wherever other long options are handled. * * \param[in] argname The long command line argument to process. * \param[in] argvalue The value of the command line argument. * \param[out] output_ty How should output be formatted? ("text", "xml", etc.) * \param[out] output_dest Where should formatted output be written to? This is * typically a filename, but could be NULL or "-". * * \return true if longname was handled, false otherwise. */ bool pcmk__parse_output_args(const char *argname, char *argvalue, char **output_ty, char **output_dest); /*! * \internal * \brief Register a new output formatter, making it available for use * the same as a base formatter. * * \param[in] fmt The new output formatter to register. * * \return 0 on success or an error code on error. */ int pcmk__register_format(const char *fmt_name, pcmk__output_factory_t create); /*! * \internal * \brief Register a function to handle a custom message. * * \note This function is for implementing custom formatters. It should not * be called directly. Instead, call out->register_message. * * \param[in,out] out The output functions structure. * \param[in] message_id The message to be handled. * \param[in] fn The custom format function to call for message_id. */ void pcmk__register_message(pcmk__output_t *out, const char *message_id, pcmk__message_fn_t fn); /*! * \internal * \brief Register an entire table of custom formatting functions at once. * * This table can contain multiple formatting functions for the same message ID * if they are for different format types. * * \param[in,out] out The output functions structure. * \param[in] table An array of ::pcmk__message_entry_t values which should * all be registered. This array must be NULL-terminated. */ void pcmk__register_messages(pcmk__output_t *out, pcmk__message_entry_t *table); /* Functions that are useful for implementing custom message formatters */ /*! * \internal * \brief A printf-like function. * * This function writes to out->dest and indents the text to the current level * of the text formatter's nesting. This should be used when implementing * custom message functions instead of printf. * * \param[in,out] out The output functions structure. */ void pcmk__indented_printf(pcmk__output_t *out, const char *format, ...) G_GNUC_PRINTF(2, 3); /*! * \internal * \brief Add the given node as a child of the current list parent. This is * used when implementing custom message functions. * * \param[in,out] out The output functions structure. * \param[in] node An XML node to be added as a child. */ void pcmk__xml_add_node(pcmk__output_t *out, xmlNodePtr node); /*! * \internal * \brief Push a parent XML node onto the stack. This is used when implementing * custom message functions. * * The XML output formatter maintains an internal stack to keep track of which nodes * are parents in order to build up the tree structure. This function can be used * to temporarily push a new node onto the stack. After calling this function, any * other formatting functions will have their nodes added as children of this new * parent. * * \param[in,out] out The output functions structure. * \param[in] node The node to be added/ */ void pcmk__xml_push_parent(pcmk__output_t *out, xmlNodePtr node); /*! * \internal * \brief Pop a parent XML node onto the stack. This is used when implementing * custom message functions. * * This function removes a parent node from the stack. See pcmk__xml_push_parent() * for more details. * * \note Little checking is done with this function. Be sure you only pop parents * that were previously pushed. In general, it is best to keep the code between * push and pop simple. * * \param[in,out] out The output functions structure. */ void pcmk__xml_pop_parent(pcmk__output_t *out); #ifdef __cplusplus } #endif #endif