sr_init/sr_exit: Improve docs, add error checks.

[libsigrok.git] / backend.c

diff --git a/backend.c b/backend.c
index 17983cd7a51a9537fffb8f5e30c5f94229f2b66c..eba03aafb5388197cb743f9cd09240ba4a28f851 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -1,7 +1,8 @@
 /*
  * This file is part of the sigrok project.
  *
- * Copyright (C) 2010 Bert Vermeulen <bert@biot.com>
+ * Copyright (C) 2010-2012 Bert Vermeulen <bert@biot.com>
+ * Copyright (C) 2012 Peter Stuge <peter@stuge.se>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -18,15 +19,77 @@
  */
 
 #include <glib.h>
-#include <sigrok.h>
+#include "libsigrok.h"
+#include "libsigrok-internal.h"
 
-int sr_init(void)
+/**
+ * Initialize libsigrok.
+ *
+ * This function must be called before any other libsigrok function.
+ *
+ * @param ctx Pointer to a libsigrok context struct pointer. Must not be NULL.
+ *            This will be a pointer to a newly allocated libsigrok context
+ *            object upon success, and is undefined upon errors.
+ *
+ * @return SR_OK upon success, a (negative) error code otherwise. Upon errors
+ *         the 'ctx' pointer is undefined and should not be used. Upon success,
+ *         the context will be free'd by sr_exit() as part of the libsigrok
+ *         shutdown.
+ */
+SR_API int sr_init(struct sr_context **ctx)
 {
-       return load_hwplugins();
+       int ret = SR_ERR;
+       struct sr_context *context;
+
+       if (!ctx) {
+               sr_err("%s(): libsigrok context was NULL.", __func__);
+               return SR_ERR;
+       }
+
+       /* + 1 to handle when struct sr_context has no members. */
+       context = g_try_malloc0(sizeof(struct sr_context) + 1);
+
+       if (!context) {
+               ret = SR_ERR_MALLOC;
+               goto done;
+       }
+
+#ifdef HAVE_LIBUSB_1_0
+       ret = libusb_init(&context->libusb_ctx);
+       if (LIBUSB_SUCCESS == ret) {
+               sr_err("libusb_init() returned %s.\n", libusb_error_name(ret));
+               goto done;
+       }
+#endif
+
+       *ctx = context;
+       ret = SR_OK;
+
+done:
+       return ret;
 }
 
-/* TODO: Should return int to be able to report back error codes. */
-void sr_exit(void)
+/**
+ * Shutdown libsigrok.
+ *
+ * @param ctx Pointer to a libsigrok context struct. Must not be NULL.
+ *
+ * @return SR_OK upon success, a (negative) error code otherwise.
+ */
+SR_API int sr_exit(struct sr_context *ctx)
 {
-       sr_device_close_all();
+       if (!ctx) {
+               sr_err("%s(): libsigrok context was NULL.", __func__);
+               return SR_ERR;
+       }
+
+       sr_hw_cleanup_all();
+
+#ifdef HAVE_LIBUSB_1_0
+       libusb_exit(ctx->libusb_ctx);
+#endif
+
+       g_free(ctx);
+
+       return SR_OK;
 }