lib/igt_core: api documentation

At most a bit of comment of function declaration movement for more
polish. One tricky bit is to #ifdef out (only for gtkdoc of course)
the struct option; forward declaration - gtkdoc needlessly lists it.

FIXME: The struct documentation for igt_helper_process somehow doesn't
get picked up ... Same issue seems to be with the igt_log_level enum,
I've shoveled the relevant documentation into igt_log in free-form for
now.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 226 insertions, 72 deletions

diff --git a/lib/igt_core.h b/lib/igt_core.h
index 1ec0bfcb..0e3d7be0 100644
--- a/lib/igt_core.h
+++ b/lib/igt_core.h
@@ -30,8 +30,6 @@
 #ifndef IGT_CORE_H
 #define IGT_CORE_H
 
-bool igt_only_list_subtests(void);
-
 bool __igt_fixture(void);
 void __igt_fixture_complete(void);
 void __igt_fixture_end(void) __attribute__((noreturn));
@@ -56,25 +54,42 @@ void __igt_fixture_end(void) __attribute__((noreturn));
 jmp_buf igt_subtest_jmpbuf;
 void igt_subtest_init(int argc, char **argv);
 typedef int (*igt_opt_handler_t)(int opt, int opt_index);
+#ifndef __GTK_DOC_IGNORE__ /* gtkdoc wants to document this forward decl */
 struct option;
+#endif
 int igt_subtest_init_parse_opts(int argc, char **argv,
 				const char *extra_short_opts,
 				struct option *extra_long_opts,
 				const char *help_str,
-				igt_opt_handler_t opt_handler);
+				igt_opt_handler_t extra_opt_handler);
 
 bool __igt_run_subtest(const char *subtest_name);
+#define __igt_tokencat2(x, y) x ## y
+
+/**
+ * igt_tokencat:
+ * @x: first variable
+ * @y: second variable
+ *
+ * C preprocessor helper to concatenate two variables while properly expanding
+ * them.
+ */
+#define igt_tokencat(x, y) __igt_tokencat2(x, y)
+
 /**
  * igt_subtest:
+ * @name: name of the subtest
  *
- * Denote a subtest code block
+ * This is a magic control flow block which denotes a subtest code block. Within
+ * that codeblock igt_skip|success will only bail out of the subtest. The _f
+ * variant accepts a printf format string, which is useful for constructing
+ * combinatorial tests.
  *
- * Magic control flow which denotes a subtest code block. Within that codeblock
- * igt_skip|success will only bail out of the subtest. The _f variant accepts a
- * printf format string, which is useful for constructing combinatorial tests.
+ * This is a simpler version of igt_subtest_f()
  */
-#define igt_tokencat2(x, y) x ## y
-#define igt_tokencat(x, y) igt_tokencat2(x, y)
+#define igt_subtest(name) for (; __igt_run_subtest((name)) && \
+				   (setjmp(igt_subtest_jmpbuf) == 0); \
+				   igt_success())
 #define __igt_subtest_f(tmp, format...) \
 	for (char tmp [256]; \
 	     snprintf( tmp , sizeof( tmp ), \
@@ -85,18 +100,29 @@ bool __igt_run_subtest(const char *subtest_name);
 
 /**
  * igt_subtest_f:
- * @...: format string
+ * @...: format string and optional arguments
  *
- * Denote a subtest code block
+ * This is a magic control flow block which denotes a subtest code block. Within
+ * that codeblock igt_skip|success will only bail out of the subtest. The _f
+ * variant accepts a printf format string, which is useful for constructing
+ * combinatorial tests.
  *
- * Like #igt_subtest, but also accepts a printf format string
+ * Like igt_subtest(), but also accepts a printf format string instead of a
+ * static string.
  */
 #define igt_subtest_f(f...) \
 	__igt_subtest_f(igt_tokencat(__tmpchar, __LINE__), f)
-#define igt_subtest(name) for (; __igt_run_subtest((name)) && \
-				   (setjmp(igt_subtest_jmpbuf) == 0); \
-				   igt_success())
+
 const char *igt_subtest_name(void);
+bool igt_only_list_subtests(void);
+
+/**
+ * igt_main:
+ *
+ * This is a magic control flow block used instead of a main() function for
+ * tests with subtests. Open-coding the main() function is only recommended if
+ * the test needs to parse additional cmdline arguments of its own.
+ */
 #define igt_main \
 	static void igt_tokencat(__real_main, __LINE__)(void); \
 	int main(int argc, char **argv) { \
@@ -112,6 +138,14 @@ const char *igt_subtest_name(void);
  * Init for simple tests without subtests
  */
 void igt_simple_init(void);
+
+/**
+ * igt_simple_main:
+ *
+ * This is a magic control flow block used instead of a main() function for
+ * simple tests. Open-coding the main() function is only recommended if
+ * the test needs to parse additional cmdline arguments of its own.
+ */
 #define igt_simple_main \
 	static void igt_tokencat(__real_main, __LINE__)(void); \
 	int main(int argc, char **argv) { \
@@ -121,62 +155,27 @@ void igt_simple_init(void);
 	} \
 	static void igt_tokencat(__real_main, __LINE__)(void) \
 
-/**
- * igt_skip:
- *
- * Subtest aware test skipping
- *
- * For tests with subtests this will either bail out of the current subtest or
- * mark all subsequent subtests as SKIP (in case some global setup code failed).
- *
- * For normal tests without subtest it will directly exit.
- */
 __attribute__((format(printf, 1, 2)))
 void igt_skip(const char *f, ...) __attribute__((noreturn));
 __attribute__((format(printf, 5, 6)))
 void __igt_skip_check(const char *file, const int line,
 		      const char *func, const char *check,
 		      const char *format, ...) __attribute__((noreturn));
-/**
- * igt_success:
- *
- * Complete a (subtest) as successfull
- *
- * This bails out of a subtests and marks it as successful. For global tests it
- * it won't bail out of anything.
- */
 void igt_success(void);
 
-/**
- * igt_fail:
- *
- * Fail a testcase
- *
- * For subtest it just bails out of the subtest, when run in global context it
- * will exit. Note that it won't attempt to keep on running further tests,
- * presuming that some mandatory setup failed.
- */
 void igt_fail(int exitcode) __attribute__((noreturn));
 __attribute__((format(printf, 6, 7)))
 void __igt_fail_assert(int exitcode, const char *file,
 		       const int line, const char *func, const char *assertion,
 		       const char *format, ...)
 	__attribute__((noreturn));
-/**
- * igt_exit:
- *
- * exit() for igts
- *
- * This will exit the test with the right exit code when subtests have been
- * skipped. For normal tests it exits with a successful exit code, presuming
- * everything has worked out. For subtests it also checks that at least one
- * subtest has been run (save when only listing subtests.
- */
 void igt_exit(void) __attribute__((noreturn));
+
 /**
  * igt_assert:
+ * @expr: condition to test
  *
- * Fails (sub-)test if a condition is not met
+ * Fails (sub-)test if the condition is not met
  *
  * Should be used everywhere where a test checks results.
  */
@@ -184,14 +183,36 @@ void igt_exit(void) __attribute__((noreturn));
 	do { if (!(expr)) \
 		__igt_fail_assert(99, __FILE__, __LINE__, __func__, #expr , NULL); \
 	} while (0)
+
+/**
+ * igt_assert_f:
+ * @expr: condition to test
+ * @...: format string and optional arguments
+ *
+ * Fails (sub-)test if the condition is not met
+ *
+ * Should be used everywhere where a test checks results.
+ *
+ * In addition to the plain igt_assert() helper this allows to print additional
+ * information to help debugging test failures.
+ */
 #define igt_assert_f(expr, f...) \
 	do { if (!(expr)) \
 		__igt_fail_assert(99, __FILE__, __LINE__, __func__, #expr , f); \
 	} while (0)
+
 /**
- * igt_assert_cmptint:
+ * igt_assert_cmpint:
+ * @n1: first value
+ * @cmp: compare operator
+ * @n2: second value
+ *
+ * Fails (sub-)test if the condition is not met
+ *
+ * Should be used everywhere where a test compares two integer values.
  *
- * Like #igt_assert, but displays the values being compared on failure.
+ * Like igt_assert(), but displays the values being compared on failure instead
+ * of simply printing the stringified expression.
  */
 #define igt_assert_cmpint(n1, cmp, n2) \
 	do { \
@@ -204,18 +225,61 @@ void igt_exit(void) __attribute__((noreturn));
 
 /**
  * igt_require:
+ * @expr: condition to test
  *
- * Skip a (sub-)test if a condition is not met
+ * Skip a (sub-)test if a condition is not met.
  *
- * This is useful to streamline the skip logic since it allows for a more flat
- * code control flow.
+ * Should be used everywhere where a test checks results to decide about
+ * skipping. This is useful to streamline the skip logic since it allows for a more flat
+ * code control flow, similar to igt_assert()
  */
 #define igt_require(expr) igt_skip_on(!(expr))
+
+/**
+ * igt_skip_on:
+ * @expr: condition to test
+ *
+ * Skip a (sub-)test if a condition is met.
+ *
+ * Should be used everywhere where a test checks results to decide about
+ * skipping. This is useful to streamline the skip logic since it allows for a more flat
+ * code control flow, similar to igt_assert()
+ */
 #define igt_skip_on(expr) \
 	do { if ((expr)) \
 		__igt_skip_check(__FILE__, __LINE__, __func__, #expr , NULL); \
 	} while (0)
+
+/**
+ * igt_require_f:
+ * @expr: condition to test
+ * @...: format string and optional arguments
+ *
+ * Skip a (sub-)test if a condition is not met.
+ *
+ * Should be used everywhere where a test checks results to decide about
+ * skipping. This is useful to streamline the skip logic since it allows for a more flat
+ * code control flow, similar to igt_assert()
+ *
+ * In addition to the plain igt_require() helper this allows to print additional
+ * information to help debugging test failures.
+ */
 #define igt_require_f(expr, f...) igt_skip_on_f(!(expr), f)
+
+/**
+ * igt_skip_on_f:
+ * @expr: condition to test
+ * @...: format string and optional arguments
+ *
+ * Skip a (sub-)test if a condition is met.
+ *
+ * Should be used everywhere where a test checks results to decide about
+ * skipping. This is useful to streamline the skip logic since it allows for a more flat
+ * code control flow, similar to igt_assert()
+ *
+ * In addition to the plain igt_skip_on() helper this allows to print additional
+ * information to help debugging test failures.
+ */
 #define igt_skip_on_f(expr, f...) \
 	do { if ((expr)) \
 		__igt_skip_check(__FILE__, __LINE__, __func__, #expr , f); \
@@ -223,21 +287,37 @@ void igt_exit(void) __attribute__((noreturn));
 
 /* fork support code */
 bool __igt_fork(void);
+
 /**
  * igt_fork:
  * @child: name of the int variable with the child number
  * @num_children: number of children to fork
  *
- * Fork parallel test threads with fork()
+ * This is a magic control flow block which spawns parallel test threads with
+ * fork().
+ *
+ * The test children execute in parallel to the main test thread. Joining all
+ * test threads should be done with igt_waitchildren to ensure that the exit
+ * codes of all children are properly reflected in the test status.
  *
- * Joining all test threads should be done with igt_waitchildren to ensure that
- * the exit codes of all children are properly reflected in the test status.
+ * Note that igt_skip() will not be forwarded, feature tests need to be done
+ * before spawning threads with igt_fork().
  */
 #define igt_fork(child, num_children) \
 	for (int child = 0; child < (num_children); child++) \
 		for (; __igt_fork(); exit(0))
 void igt_waitchildren(void);
 
+/**
+ * igt_helper_process_t:
+ * @running: indicates whether the process is currently running
+ * @use_SIGKILL: whether the helper should be terminated with SIGKILL or SIGQUIT
+ * @pid: pid of the helper if @running is true
+ * @id: internal id
+ *
+ * Tracking structure for helper processes. Users of the i-g-t library should
+ * only set @use_SIGKILL directly.
+ */
 struct igt_helper_process {
 	bool running;
 	bool use_SIGKILL;
@@ -245,12 +325,40 @@ struct igt_helper_process {
 	int id;
 };
 bool __igt_fork_helper(struct igt_helper_process *proc);
-void igt_stop_helper(struct igt_helper_process *proc);
-void igt_wait_helper(struct igt_helper_process *proc);
+
+/**
+ * igt_fork_helper:
+ * @proc: #igt_helper_process structure
+ *
+ * This is a magic control flow block which denotes an asynchronous helper
+ * process block. The difference compared to igt_fork() is that failures from
+ * the child process will not be forwarded, making this construct more suitable
+ * for background processes. Common use cases are regular interference of the
+ * main test thread through e.g. sending signals or evicting objects through
+ * debugfs. Through the explicit #igt_helper_process they can also be controlled
+ * in a more fine-grained way than test children spawned through igt_fork().
+ *
+ * For tests with subtest helper process can be started outside of a
+ * #igt_subtest block.
+ *
+ * Calling igt_wait_helper() joins a helper process and igt_stop_helper()
+ * forcefully terminates it.
+ */
 #define igt_fork_helper(proc) \
 	for (; __igt_fork_helper(proc); exit(0))
+void igt_wait_helper(struct igt_helper_process *proc);
+void igt_stop_helper(struct igt_helper_process *proc);
 
 /* exit handler code */
+
+/**
+ * igt_exit_handler_t:
+ * @sig: Signal number which caused the exit or 0.
+ *
+ * Exit handler type used by igt_install_exit_handler(). Note that exit handlers
+ * can potentially be run from signal handling contexts, the @sig parameter can
+ * be used to figure this out and act accordingly.
+ */
 typedef void (*igt_exit_handler_t)(int sig);
 
 /* reliable atexit helpers, also work when killed by a signal (if possible) */
@@ -260,18 +368,16 @@ void igt_disable_exit_handler(void);
 
 /* helpers to automatically reduce test runtime in simulation */
 bool igt_run_in_simulation(void);
-#define SLOW_QUICK(slow,quick) (igt_run_in_simulation() ? (quick) : (slow))
 /**
- * igt_skip_on_simulation:
- *
- * Skip tests when INTEL_SIMULATION env war is set
+ * SLOW_QUICK:
+ * @slow: value in simulation mode
+ * @quick: value in normal mode
  *
- * Skip the test when running on simulation (and that's relevant only when
- * we're not in the mode where we list the subtests).
- *
- * This function is subtest aware (since it uses igt_skip) and so can be used to
- * skip specific subtests or all subsequent subtests.
+ * Simple macro to select between two values (e.g. number of test rounds or test
+ * buffer size) depending upon whether i-g-t is run in simulation mode or not.
  */
+#define SLOW_QUICK(slow,quick) (igt_run_in_simulation() ? (quick) : (slow))
+
 void igt_skip_on_simulation(void);
 
 /* structured logging */
@@ -283,16 +389,64 @@ enum igt_log_level {
 };
 __attribute__((format(printf, 2, 3)))
 void igt_log(enum igt_log_level level, const char *format, ...);
+
+/**
+ * igt_debug:
+ * @...: format string and optional arguments
+ *
+ * Wrapper for igt_log for message at the IGT_LOG_DEBUG level.
+ */
 #define igt_debug(f...) igt_log(IGT_LOG_DEBUG, f)
+
+/**
+ * igt_info:
+ * @...: format string and optional arguments
+ *
+ * Wrapper for igt_log for message at the IGT_LOG_INFO level.
+ */
 #define igt_info(f...) igt_log(IGT_LOG_INFO, f)
+
+/**
+ * igt_warn:
+ * @...: format string and optional arguments
+ *
+ * Wrapper for igt_log for message at the IGT_LOG_WARN level.
+ */
 #define igt_warn(f...) igt_log(IGT_LOG_WARN, f)
 extern enum igt_log_level igt_log_level;
 
+/**
+ * igt_warn_on:
+ * @condition: condition to test
+ *
+ * Print a IGT_LOG_WARN level message if a condition is not met.
+ *
+ * Should be used everywhere where a test checks results to decide about
+ * printing warnings. This is useful to streamline the test logic since it
+ * allows for a more flat code control flow, similar to igt_assert()
+ */
 #define igt_warn_on(condition) do {\
 		if (condition) \
 			igt_warn("Warning on condition %s in fucntion %s, file %s:%i\n", \
 				 #condition, __func__, __FILE__, __LINE__); \
 	} while (0)
+
+/**
+ * igt_warn_on_f:
+ * @condition: condition to test
+ * @...: format string and optional arguments
+ *
+ * Skip a (sub-)test if a condition is not met.
+ *
+ * Print a IGT_LOG_WARN level message if a condition is not met.
+ *
+ * Should be used everywhere where a test checks results to decide about
+ * printing warnings. This is useful to streamline the test logic since it
+ * allows for a more flat code control flow, similar to igt_assert()
+ *
+ * In addition to the plain igt_warn_on_f() helper this allows to print
+ * additional information (again as warnings) to help debugging test failures.
+ */
 #define igt_warn_on_f(condition, f...) do {\
 		if (condition) {\
 			igt_warn("Warning on condition %s in fucntion %s, file %s:%i\n", \