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authorVolker Lendecke <vl@samba.org>2008-06-28 23:13:05 +0200
committerVolker Lendecke <vl@samba.org>2008-07-26 12:59:41 +0200
commitbdf1747c98e0622dd4b91fa1f45551d0c5c3ca4c (patch)
treeba90d2c93d77dfe5fc70d3abbe136adce33caa09
parent042600cbac2856b88b29b5589caebed9d699a8a3 (diff)
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Create doxygen comments for async_req.[ch]
(This used to be commit 1dab45b16a23b1126fbf29890747a2b256f08968)
-rw-r--r--source3/include/async_req.h123
-rw-r--r--source3/lib/async_req.c84
2 files changed, 162 insertions, 45 deletions
diff --git a/source3/include/async_req.h b/source3/include/async_req.h
index fb463d5b9a..2d01b53814 100644
--- a/source3/include/async_req.h
+++ b/source3/include/async_req.h
@@ -22,75 +22,116 @@
#include "includes.h"
-/*
- * An async request moves between the following 4 states.
+/**
+ * An async request moves between the following 4 states:
*/
+
enum async_req_state {
- ASYNC_REQ_INIT, /* we are creating the request */
- ASYNC_REQ_IN_PROGRESS, /* we are waiting the request to complete */
- ASYNC_REQ_DONE, /* the request is finished */
- ASYNC_REQ_ERROR }; /* an error has occured */
+ /**
+ * we are creating the request
+ */
+ ASYNC_REQ_INIT,
+ /**
+ * we are waiting the request to complete
+ */
+ ASYNC_REQ_IN_PROGRESS,
+ /**
+ * the request is finished
+ */
+ ASYNC_REQ_DONE,
+ /**
+ * an error has occured
+ */
+ ASYNC_REQ_ERROR
+};
+
+/**
+ * @brief An async request
+ *
+ * This represents an async request being processed by callbacks via an event
+ * context. A user can issue for example a write request to a socket, giving
+ * an implementation function the fd, the buffer and the number of bytes to
+ * transfer. The function issuing the request will immediately return without
+ * blocking most likely without having sent anything. The API user then fills
+ * in req->async.fn and req->async.priv, functions that are called when the
+ * request is finished.
+ *
+ * It is up to the user of the async request to talloc_free it after it has
+ * finished. This can happen while the completion function is called.
+ */
struct async_req {
- /* the external state - will be queried by the caller */
+ /**
+ * @brief The external state - will be queried by the caller
+ *
+ * While the async request is being processed, state will remain in
+ * ASYNC_REQ_IN_PROGRESS. A request is finished if
+ * req->state>=ASYNC_REQ_DONE.
+ */
enum async_req_state state;
- /* a private pointer for use by the async function implementation */
+ /**
+ * @brief Private pointer for the actual implementation
+ *
+ * The implementation doing the work for the async request needs a
+ * current state like for example a fd event. The user of an async
+ * request should not touch this.
+ */
void *private_data;
- /* print yourself, for debugging purposes */
+ /**
+ * @brief Print yourself, for debugging purposes
+ *
+ * Async requests are opaque data structures. The implementation of an
+ * async request can define a custom function to print more debug
+ * info.
+ */
char *(*print)(TALLOC_CTX *mem_ctx, struct async_req *);
- /* status code when finished */
+ /**
+ * @brief status code when finished
+ *
+ * This status can be queried in the async completion function. It
+ * will be set to NT_STATUS_OK when everything went fine.
+ **/
NTSTATUS status;
- /* the event context we are using */
+ /**
+ * @brief The event context we are using
+ *
+ * The event context that this async request works on.
+ */
struct event_context *event_ctx;
- /* information on what to do on completion */
+ /**
+ * @brief What to do on completion
+ *
+ * This is used for the user of an async request, fn is called when
+ * the request completes, either successfully or with an error.
+ */
struct {
+ /**
+ * @brief Completion function
+ * Completion function, to be filled by the API user
+ */
void (*fn)(struct async_req *);
+ /**
+ * @brief Private data for the completion function
+ */
void *priv;
} async;
};
-/*
- * Print an async_req structure for debugging purposes
- */
-char *async_req_print(TALLOC_CTX *mem_ctx, struct async_req *req);
-
-/*
- * Create an async request
- */
struct async_req *async_req_new(TALLOC_CTX *mem_ctx, struct event_context *ev);
-/*
- * An async request has successfully finished, invoke the callback
- */
+char *async_req_print(TALLOC_CTX *mem_ctx, struct async_req *req);
+
void async_req_done(struct async_req *req);
-/*
- * An async request has seen an error, invoke the callback
- */
void async_req_error(struct async_req *req, NTSTATUS status);
-/*
- * If a request is finished or ends in error even before it has the chance to
- * trigger the event loop, post a status. This creates an immediate timed
- * event to call the async function if there is any.
- */
bool async_post_status(struct async_req *req, NTSTATUS status);
-/*
- * Convenience helper to easily check alloc failure within a callback.
- *
- * Call pattern would be
- * p = talloc(mem_ctx, bla);
- * if (async_req_nomem(p, req)) {
- * return;
- * }
- *
- */
bool async_req_nomem(const void *p, struct async_req *req);
#endif
diff --git a/source3/lib/async_req.c b/source3/lib/async_req.c
index 2e85d9a38d..501a6b5524 100644
--- a/source3/lib/async_req.c
+++ b/source3/lib/async_req.c
@@ -19,6 +19,20 @@
#include "includes.h"
+/**
+ * @brief Print an async_req structure
+ * @param[in] mem_ctx The memory context for the result
+ * @param[in] req The request to be printed
+ * @retval Text representation of req
+ *
+ * This is a default print function for async requests. Implementations should
+ * override this with more specific information.
+ *
+ * This function should not be used by async API users, this is non-static
+ * only to allow implementations to easily provide default information in
+ * their specific functions.
+ */
+
char *async_req_print(TALLOC_CTX *mem_ctx, struct async_req *req)
{
return talloc_asprintf(mem_ctx, "async_req: state=%d, status=%s, "
@@ -26,6 +40,15 @@ char *async_req_print(TALLOC_CTX *mem_ctx, struct async_req *req)
talloc_get_name(req->private_data));
}
+/**
+ * @brief Create an async request
+ * @param[in] mem_ctx The memory context for the result
+ * @param[in] ev The event context this async request will be driven by
+ * @retval A new async request
+ *
+ * The new async request will be initialized in state ASYNC_REQ_IN_PROGRESS
+ */
+
struct async_req *async_req_new(TALLOC_CTX *mem_ctx, struct event_context *ev)
{
struct async_req *result;
@@ -40,6 +63,15 @@ struct async_req *async_req_new(TALLOC_CTX *mem_ctx, struct event_context *ev)
return result;
}
+/**
+ * @brief An async request has successfully finished
+ * @param[in] req The finished request
+ *
+ * async_req_done is to be used by implementors of async requests. When a
+ * request is successfully finished, this function calls the user's completion
+ * function.
+ */
+
void async_req_done(struct async_req *req)
{
req->status = NT_STATUS_OK;
@@ -49,6 +81,16 @@ void async_req_done(struct async_req *req)
}
}
+/**
+ * @brief An async request has seen an error
+ * @param[in] req The request with an error
+ * @param[in] status The error code
+ *
+ * async_req_done is to be used by implementors of async requests. When a
+ * request can not successfully completed, the implementation should call this
+ * function with the appropriate status code.
+ */
+
void async_req_error(struct async_req *req, NTSTATUS status)
{
req->status = status;
@@ -58,6 +100,14 @@ void async_req_error(struct async_req *req, NTSTATUS status)
}
}
+/**
+ * @brief Timed event callback
+ * @param[in] ev Event context
+ * @param[in] te The timed event
+ * @param[in] now current time
+ * @param[in] priv The async request to be finished
+ */
+
static void async_trigger(struct event_context *ev, struct timed_event *te,
const struct timeval *now, void *priv)
{
@@ -72,12 +122,21 @@ static void async_trigger(struct event_context *ev, struct timed_event *te,
}
}
+/**
+ * @brief Finish a request before it started processing
+ * @param[in] req The finished request
+ * @param[in] status The success code
+ *
+ * An implementation of an async request might find that it can either finish
+ * the request without waiting for an external event, or it can't even start
+ * the engine. To present the illusion of a callback to the user of the API,
+ * the implementation can call this helper function which triggers an
+ * immediate timed event. This way the caller can use the same calling
+ * conventions, independent of whether the request was actually deferred.
+ */
+
bool async_post_status(struct async_req *req, NTSTATUS status)
{
- /*
- * Used if a request is finished before it even started
- */
-
req->status = status;
if (event_add_timed(req->event_ctx, req, timeval_zero(),
@@ -88,6 +147,23 @@ bool async_post_status(struct async_req *req, NTSTATUS status)
return true;
}
+/**
+ * @brief Helper function for nomem check
+ * @param[in] p The pointer to be checked
+ * @param[in] req The request being processed
+ *
+ * Convenience helper to easily check alloc failure within a callback
+ * implementing the next step of an async request.
+ *
+ * Call pattern would be
+ * \code
+ * p = talloc(mem_ctx, bla);
+ * if (async_req_nomem(p, req)) {
+ * return;
+ * }
+ * \endcode
+ */
+
bool async_req_nomem(const void *p, struct async_req *req)
{
if (p != NULL) {