1 files changed, 169 insertions, 0 deletions
diff --git a/src/exchange-lib/exchange_api_context.h b/src/exchange-lib/exchange_api_context.h
new file mode 100644
index 000000000..3c54bfe07
--- /dev/null
+++ b/src/exchange-lib/exchange_api_context.h
@@ -0,0 +1,169 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014, 2015 GNUnet e.V.
+
+  TALER 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.
+
+  TALER 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
+  TALER; see the file COPYING.  If not, If not, see
+  <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file exchange-lib/exchange_api_context.h
+ * @brief Internal interface to the context part of the exchange's HTTP API
+ * @author Sree Harsha Totakura <sreeharsha@totakura.in>
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <curl/curl.h>
+#include <gnunet/gnunet_util_lib.h>
+#include "taler_exchange_service.h"
+#include "taler_signatures.h"
+
+
+/**
+ * Entry in the context's job queue.
+ */
+struct MAC_Job;
+
+/**
+ * Function to call upon completion of a job.
+ *
+ * @param cls closure
+ * @param eh original easy handle (for inspection)
+ */
+typedef void
+(*MAC_JobCompletionCallback)(void *cls,
+                             CURL *eh);
+
+
+/**
+ * Schedule a CURL request to be executed and call the given @a jcc
+ * upon its completion. Note that the context will make use of the
+ * CURLOPT_PRIVATE facility of the CURL @a eh.  Applications can
+ * instead use #MAC_easy_to_closure to extract the @a jcc_cls argument
+ * from a valid @a eh afterwards.
+ *
+ * This function modifies the CURL handle to add the
+ * "Content-Type: application/json" header if @a add_json is set.
+ *
+ * @param ctx context to execute the job in
+ * @param eh curl easy handle for the request, will
+ *           be executed AND cleaned up
+ * @param add_json add "application/json" content type header
+ * @param jcc callback to invoke upon completion
+ * @param jcc_cls closure for @a jcc
+ */
+struct MAC_Job *
+MAC_job_add (struct TALER_EXCHANGE_Context *ctx,
+             CURL *eh,
+             int add_json,
+             MAC_JobCompletionCallback jcc,
+             void *jcc_cls);
+
+
+/**
+ * Obtain the `jcc_cls` argument from an `eh` that was
+ * given to #MAC_job_add().
+ *
+ * @param eh easy handle that was used
+ * @return the `jcc_cls` that was given to #MAC_job_add().
+ */
+void *
+MAC_easy_to_closure (CURL *eh);
+
+
+/**
+ * Cancel a job.  Must only be called before the job completion
+ * callback is called for the respective job.
+ *
+ * @param job job to cancel
+ */
+void
+MAC_job_cancel (struct MAC_Job *job);
+
+
+/**
+ * @brief Buffer data structure we use to buffer the HTTP download
+ * before giving it to the JSON parser.
+ */
+struct MAC_DownloadBuffer
+{
+
+  /**
+   * Download buffer
+   */
+  void *buf;
+
+  /**
+   * The size of the download buffer
+   */
+  size_t buf_size;
+
+  /**
+   * Error code (based on libc errno) if we failed to download
+   * (i.e. response too large).
+   */
+  int eno;
+
+};
+
+
+/**
+ * Callback used when downloading the reply to an HTTP request.
+ * Just appends all of the data to the `buf` in the
+ * `struct MAC_DownloadBuffer` for further processing. The size of
+ * the download is limited to #GNUNET_MAX_MALLOC_CHECKED, if
+ * the download exceeds this size, we abort with an error.
+ *
+ * Should be used by the various routines as the
+ * CURLOPT_WRITEFUNCTION.  A `struct MAC_DownloadBuffer` needs to be
+ * passed to the CURLOPT_WRITEDATA.
+ *
+ * Afterwards, `eno` needs to be checked to ensure that the download
+ * completed correctly.
+ *
+ * @param bufptr data downloaded via HTTP
+ * @param size size of an item in @a bufptr
+ * @param nitems number of items in @a bufptr
+ * @param cls the `struct KeysRequest`
+ * @return number of bytes processed from @a bufptr
+ */
+size_t
+MAC_download_cb (char *bufptr,
+                 size_t size,
+                 size_t nitems,
+                 void *cls);
+
+
+/**
+ * Obtain information about the final result about the
+ * HTTP download. If the download was successful, parses
+ * the JSON in the @a db and returns it. Also returns
+ * the HTTP @a response_code.  If the download failed,
+ * the return value is NULL.  The response code is set
+ * in any case, on download errors to zero.
+ *
+ * Calling this function also cleans up @a db.
+ *
+ * @param db download buffer
+ * @param eh CURL handle (to get the response code)
+ * @param[out] response_code set to the HTTP response code
+ *             (or zero if we aborted the download, i.e.
+ *              because the response was too big, or if
+ *              the JSON we received was malformed).
+ * @return NULL if downloading a JSON reply failed
+ */
+json_t *
+MAC_download_get_result (struct MAC_DownloadBuffer *db,
+                         CURL *eh,
+                         long *response_code);
+
+
+/* end of exchange_api_context.h */