op: lib for async operations

1 files changed, 333 insertions, 0 deletions

diff --git a/src/util/op.c b/src/util/op.c
new file mode 100644
index 000000000..41be763e5
--- /dev/null
+++ b/src/util/op.c
@@ -0,0 +1,333 @@
+/*
+     This file is part of GNUnet.
+     Copyright (C) 2016 GNUnet e.V.
+
+     GNUnet is free software; you can redistribute it and/or modify
+     it under the terms of the GNU General Public License as published
+     by the Free Software Foundation; either version 3, or (at your
+     option) any later version.
+
+     GNUnet is distributed in the hope that it will be useful, but
+     WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+     General Public License for more details.
+
+     You should have received a copy of the GNU General Public License
+     along with GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+     Boston, MA 02110-1301, USA.
+*/
+
+/**
+ * @file
+ * Asynchronous operations; register callbacks for operations and call them when a response arrives.
+ *
+ * @author Gabor X Toth
+ */
+
+#include <inttypes.h>
+
+#include "platform.h"
+#include "gnunet_util_lib.h"
+
+#define LOG(kind,...) GNUNET_log_from (kind, "util-op", __VA_ARGS__)
+
+struct OperationListItem
+{
+  struct OperationListItem *prev;
+  struct OperationListItem *next;
+
+  /**
+   * Operation ID.
+   */
+  uint64_t op_id;
+
+  /**
+   * Continuation to invoke with the result of an operation.
+   */
+  GNUNET_ResultCallback result_cb;
+
+  /**
+   * Closure for @a result_cb.
+   */
+  void *cls;
+
+  /**
+   * User context.
+   */
+  void *ctx;
+};
+
+
+/**
+ * Operations handle.
+ */
+
+struct GNUNET_OP_Handle
+{
+  /**
+   * First operation in the linked list.
+   */
+  struct OperationListItem *op_head;
+
+  /**
+   * Last operation in the linked list.
+   */
+  struct OperationListItem *op_tail;
+
+  /**
+   * Last operation ID used.
+   */
+  uint64_t last_op_id;
+};
+
+
+/**
+ * Create new operations handle.
+ */
+struct GNUNET_OP_Handle *
+GNUNET_OP_create ()
+{
+  return GNUNET_new (struct GNUNET_OP_Handle);
+}
+
+
+/**
+ * Destroy operations handle.
+ */
+void
+GNUNET_OP_destroy (struct GNUNET_OP_Handle *h)
+{
+  GNUNET_free (h);
+}
+
+
+/**
+ * Get a unique operation ID to distinguish between asynchronous requests.
+ *
+ * @param h
+ *        Operations handle.
+ *
+ * @return Operation ID to use.
+ */
+uint64_t
+GNUNET_OP_get_next_id (struct GNUNET_OP_Handle *h)
+{
+  return ++h->last_op_id;
+}
+
+
+/**
+ * Find operation by ID.
+ *
+ * @param h
+ *        Operations handle.
+ * @param op_id
+ *        Operation ID to look up.
+ *
+ * @return Operation, or NULL if not found.
+ */
+static struct OperationListItem *
+op_find (struct GNUNET_OP_Handle *h,
+         uint64_t op_id)
+{
+  struct OperationListItem *op;
+
+  for (op = h->op_head; NULL != op; op = op->next)
+    if (op->op_id == op_id)
+      return op;
+  return NULL;
+}
+
+
+/**
+ * Find operation by ID.
+ *
+ * @param h
+ *        Operations handle.
+ * @param op_id
+ *        Operation ID to look up.
+ * @param[out] result_cb
+ *        If an operation was found, its result callback is returned here.
+ * @param[out] cls
+ *        If an operation was found, its closure is returned here.
+ * @param[out] ctx
+ *        If an operation was found, its user context is returned here.
+ *
+ * @return #GNUNET_YES if an operation was found,
+ *         #GNUNET_NO  if not found.
+ */
+int
+GNUNET_OP_get (struct GNUNET_OP_Handle *h,
+               uint64_t op_id,
+               GNUNET_ResultCallback *result_cb,
+               void **cls,
+               void **ctx)
+{
+  struct OperationListItem *op = op_find (h, op_id);
+  if (NULL != op)
+  {
+    if (NULL != result_cb)
+      *result_cb = op->result_cb;
+    if (NULL != cls)
+      *cls = op->cls;
+    if (NULL != ctx)
+      *ctx = op->ctx;
+    return GNUNET_YES;
+  }
+  return GNUNET_NO;
+}
+
+
+/**
+ * Add a new operation.
+ *
+ * @param h
+ *        Operations handle.
+ * @param result_cb
+ *        Function to call with the result of the operation.
+ * @param cls
+ *        Closure for @a result_cb.
+ * @param ctx
+ *        User context.
+ *
+ * @return ID of the new operation.
+ */
+uint64_t
+GNUNET_OP_add (struct GNUNET_OP_Handle *h,
+               GNUNET_ResultCallback result_cb,
+               void *cls,
+               void *ctx)
+{
+  struct OperationListItem *op;
+
+  op = GNUNET_new (struct OperationListItem);
+  op->op_id = GNUNET_OP_get_next_id (h);
+  op->result_cb = result_cb;
+  op->cls = cls;
+  op->ctx = ctx;
+  GNUNET_CONTAINER_DLL_insert_tail (h->op_head,
+                                    h->op_tail,
+                                    op);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "%p Added operation #%" PRIu64 "\n",
+       h, op->op_id);
+  return op->op_id;
+}
+
+
+/**
+ * Remove an operation, and call its result callback (unless it was cancelled).
+ *
+ *
+ * @param h
+ *        Operations handle.
+ * @param op_id
+ *        Operation ID.
+ * @param result_code
+ *        Result of the operation.
+ * @param data
+ *        Data result of the operation.
+ * @param data_size
+ *        Size of @a data.
+ * @param[out] ctx
+ *        User context.
+ * @param cancel
+ *        Is the operation cancelled?
+ *        #GNUNET_NO  Not cancelled, result callback is called.
+ *        #GNUNET_YES Cancelled, result callback is not called.
+ *
+ * @return #GNUNET_YES if the operation was found and removed,
+ *         #GNUNET_NO  if the operation was not found.
+ */
+static int
+op_result (struct GNUNET_OP_Handle *h,
+           uint64_t op_id,
+           int64_t result_code,
+           const void *data,
+           uint16_t data_size,
+           void **ctx,
+           uint8_t cancel)
+{
+  if (0 == op_id)
+    return GNUNET_NO;
+
+  struct OperationListItem *op = op_find (h, op_id);
+  if (NULL == op)
+  {
+    LOG (GNUNET_ERROR_TYPE_WARNING,
+         "Could not find operation #%" PRIu64 "\n", op_id);
+    return GNUNET_NO;
+  }
+
+  if (NULL != ctx)
+    *ctx = op->ctx;
+
+  GNUNET_CONTAINER_DLL_remove (h->op_head,
+                               h->op_tail,
+                               op);
+
+  if ( (GNUNET_YES != cancel) &&
+       (NULL != op->result_cb) )
+    op->result_cb (op->cls,
+                   result_code, data,
+                   data_size);
+  GNUNET_free (op);
+  return GNUNET_YES;
+}
+
+
+/**
+ * Call the result callback of an operation and remove it.
+ *
+ * @param h
+ *        Operations handle.
+ * @param op_id
+ *        Operation ID.
+ * @param result_code
+ *        Result of the operation.
+ * @param data
+ *        Data result of the operation.
+ * @param data_size
+ *        Size of @a data.
+ * @param[out] ctx
+ *        User context.
+ *
+ * @return #GNUNET_YES if the operation was found and removed,
+ *         #GNUNET_NO  if the operation was not found.
+ */
+int
+GNUNET_OP_result (struct GNUNET_OP_Handle *h,
+                  uint64_t op_id,
+                  int64_t result_code,
+                  const void *data,
+                  uint16_t data_size,
+                  void **ctx)
+{
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "%p Received result for operation #%" PRIu64 ": %" PRId64 " (size: %u)\n",
+       h, op_id, result_code, data_size);
+  return op_result (h, op_id, result_code, data, data_size, ctx, GNUNET_NO);
+}
+
+
+/**
+ * Remove / cancel an operation.
+ *
+ * @param h
+ *        Operations handle.
+ * @param op_id
+ *        Operation ID.
+ *
+ * @return #GNUNET_YES if the operation was found and removed,
+ *         #GNUNET_NO  if the operation was not found.
+ */
+int
+GNUNET_OP_remove (struct GNUNET_OP_Handle *h,
+                  uint64_t op_id)
+{
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "%p Cancelling operation #%" PRIu64  "\n",
+       h, op_id);
+  return op_result (h, op_id, 0, NULL, 0, NULL, GNUNET_YES);
+}