Merge branch 'variadic-enumerators'

This adds several changes to enumerator_t and linked_list_t to improve
portability.  In particular to Apple's ARM64 iOS platform, whose calling
convention for variadic and regular functions are different.  This means
that assigning a non-variadic function to a variadic function pointer,
as we did with our enumerator_t::enumerate() implementations and several
callbacks, will result in crashes as the called function will access the
arguments differently than the caller provided them.

To avoid this issue the enumerator_t interface is now fully variadic.
A new mandatory method is added, venumerate(), that takes a va_list with
the arguments provided while enumerating.  enumerate() is replaced with
a generic implementation that prepares a va_list and calls the
enumerator's venumerate() implementation.  As this allows passing the
arguments of one enumerator to another it avoids the five pointer hack
used by enumerator_create_nested() and enumerator_create_cleaner().
To simplify the implementation of venumerate() a helper macro is provided
that assigns values from a given va_list to local variables.

The signature of the callback passed to enumerator_create_filter() has
also changed significantly.  It's now required to enumerate over the
original enumerator in the callback as this avoids the previous in/out
pointer hack. The arguments to the outer enumerator are provided in a
va_list.

Similar changes to avoid such five pointer hacks affect the signatures
of the callbacks for linked_list_t's invoke_function() and find_first()
methods.  For the latter the return type also changed from status_t to
bool, which is important as SUCCESS is defined as 0, so checks for ==
SUCCESS will now fail.

1 files changed, 15 insertions, 18 deletions

diff --git a/src/libstrongswan/plugins/sqlite/sqlite_database.c b/src/libstrongswan/plugins/sqlite/sqlite_database.c
index 0a35e3017..9f874212e 100644
--- a/src/libstrongswan/plugins/sqlite/sqlite_database.c
+++ b/src/libstrongswan/plugins/sqlite/sqlite_database.c
@@ -174,10 +174,8 @@ typedef struct {
 	private_sqlite_database_t *database;
 } sqlite_enumerator_t;
 
-/**
- * destroy a sqlite enumerator
- */
-static void sqlite_enumerator_destroy(sqlite_enumerator_t *this)
+METHOD(enumerator_t, sqlite_enumerator_destroy, void,
+	sqlite_enumerator_t *this)
 {
 	sqlite3_finalize(this->stmt);
 	if (!is_threadsave())
@@ -188,13 +186,10 @@ static void sqlite_enumerator_destroy(sqlite_enumerator_t *this)
 	free(this);
 }
 
-/**
- * Implementation of database.query().enumerate
- */
-static bool sqlite_enumerator_enumerate(sqlite_enumerator_t *this, ...)
+METHOD(enumerator_t, sqlite_enumerator_enumerate, bool,
+	sqlite_enumerator_t *this, va_list args)
 {
 	int i;
-	va_list args;
 
 	switch (sqlite3_step(this->stmt))
 	{
@@ -207,7 +202,7 @@ static bool sqlite_enumerator_enumerate(sqlite_enumerator_t *this, ...)
 		case SQLITE_DONE:
 			return FALSE;
 	}
-	va_start(args, this);
+
 	for (i = 0; i < this->count; i++)
 	{
 		switch (this->columns[i])
@@ -245,11 +240,9 @@ static bool sqlite_enumerator_enumerate(sqlite_enumerator_t *this, ...)
 			}
 			default:
 				DBG1(DBG_LIB, "invalid result type supplied");
-				va_end(args);
 				return FALSE;
 		}
 	}
-	va_end(args);
 	return TRUE;
 }
 
@@ -270,13 +263,17 @@ METHOD(database_t, query, enumerator_t*,
 	stmt = run(this, sql, &args);
 	if (stmt)
 	{
-		enumerator = malloc_thing(sqlite_enumerator_t);
-		enumerator->public.enumerate = (void*)sqlite_enumerator_enumerate;
-		enumerator->public.destroy = (void*)sqlite_enumerator_destroy;
-		enumerator->stmt = stmt;
-		enumerator->count = sqlite3_column_count(stmt);
+		INIT(enumerator,
+			.public = {
+				.enumerate = enumerator_enumerate_default,
+				.venumerate = _sqlite_enumerator_enumerate,
+				.destroy = _sqlite_enumerator_destroy,
+			},
+			.stmt = stmt,
+			.count = sqlite3_column_count(stmt),
+			.database = this,
+		);
 		enumerator->columns = malloc(sizeof(db_type_t) * enumerator->count);
-		enumerator->database = this;
 		for (i = 0; i < enumerator->count; i++)
 		{
 			enumerator->columns[i] = va_arg(args, db_type_t);