libjaylink/core.c

   1 /*
   2  * This file is part of the libjaylink project.
   3  *
   4  * Copyright (C) 2014-2016 Marc Schink <jaylink-dev@marcschink.de>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdlib.h>
  21 #ifdef _WIN32
  22 #include <winsock2.h>
  23 #endif
  24 #include <libusb.h>
  25
  26 #include "libjaylink.h"
  27 #include "libjaylink-internal.h"
  28
  29 /**
  30  * @mainpage
  31  *
  32  * @section sec_intro Introduction
  33  *
  34  * This document describes the API of libjaylink.
  35  *
  36  * libjaylink is a shared library written in C to access SEGGER J-Link and
  37  * compatible devices.
  38  *
  39  * @section sec_error Error handling
  40  *
  41  * The libjaylink functions which can fail use the return value to indicate an
  42  * error. The functions typically return an error code of #jaylink_error.
  43  * For each function, all possible error codes and their detailed descriptions
  44  * are documented. As the possible error codes returned by a function may
  45  * change it is recommended to also always cover unexpected values when
  46  * checking for error codes to be compatible with later versions of libjaylink.
  47  *
  48  * There are a few exceptions where a function directly returns the result
  49  * instead of an error code because it is more convenient from an API
  50  * perspective and because there is only a single reason for failure which is
  51  * clearly distinguishable from the result.
  52  *
  53  * @section sec_license License
  54  *
  55  * libjaylink is licensed under the terms of the GNU General Public
  56  * License (GPL), version 2 or later.
  57  */
  58
  59 /**
  60  * @file
  61  *
  62  * Core library functions.
  63  */
  64
  65 /**
  66  * Initialize libjaylink.
  67  *
  68  * This function must be called before any other libjaylink function is called.
  69  *
  70  * @param[out] ctx Newly allocated libjaylink context on success, and undefined
  71  *                 on failure.
  72  *
  73  * @retval JAYLINK_OK Success.
  74  * @retval JAYLINK_ERR_ARG Invalid arguments.
  75  * @retval JAYLINK_ERR_MALLOC Memory allocation error.
  76  * @retval JAYLINK_ERR Other error conditions.
  77  *
  78  * @since 0.1.0
  79  */
  80 JAYLINK_API int jaylink_init(struct jaylink_context **ctx)
  81 {
  82         int ret;
  83         struct jaylink_context *context;
  84 #ifdef _WIN32
  85         WSADATA wsa_data;
  86 #endif
  87
  88         if (!ctx)
  89                 return JAYLINK_ERR_ARG;
  90
  91         context = malloc(sizeof(struct jaylink_context));
  92
  93         if (!context)
  94                 return JAYLINK_ERR_MALLOC;
  95
  96         if (libusb_init(&context->usb_ctx) != LIBUSB_SUCCESS) {
  97                 free(context);
  98                 return JAYLINK_ERR;
  99         }
 100
 101 #ifdef _WIN32
 102         ret = WSAStartup(MAKEWORD(2, 2), &wsa_data);
 103
 104         if (ret != 0) {
 105                 libusb_exit(context->usb_ctx);
 106                 free(context);
 107                 return JAYLINK_ERR;
 108         }
 109
 110         if (LOBYTE(wsa_data.wVersion) != 2 || HIBYTE(wsa_data.wVersion) != 2) {
 111                 libusb_exit(context->usb_ctx);
 112                 free(context);
 113                 return JAYLINK_ERR;
 114         }
 115 #endif
 116
 117         context->devs = NULL;
 118         context->discovered_devs = NULL;
 119
 120         /* Show error and warning messages by default. */
 121         context->log_level = JAYLINK_LOG_LEVEL_WARNING;
 122
 123         context->log_callback = &log_vprintf;
 124         context->log_callback_data = NULL;
 125
 126         ret = jaylink_log_set_domain(context, JAYLINK_LOG_DOMAIN_DEFAULT);
 127
 128         if (ret != JAYLINK_OK) {
 129 #ifdef _WIN32
 130                 WSACleanup();
 131 #endif
 132                 free(context);
 133                 return ret;
 134         }
 135
 136         *ctx = context;
 137
 138         return JAYLINK_OK;
 139 }
 140
 141 /**
 142  * Shutdown libjaylink.
 143  *
 144  * @param[in,out] ctx libjaylink context.
 145  *
 146  * @retval JAYLINK_OK Success.
 147  * @retval JAYLINK_ERR_ARG Invalid arguments.
 148  *
 149  * @since 0.1.0
 150  */
 151 JAYLINK_API int jaylink_exit(struct jaylink_context *ctx)
 152 {
 153         struct list *item;
 154
 155         if (!ctx)
 156                 return JAYLINK_ERR_ARG;
 157
 158         item = ctx->discovered_devs;
 159
 160         while (item) {
 161                 jaylink_unref_device((struct jaylink_device *)item->data);
 162                 item = item->next;
 163         }
 164
 165         list_free(ctx->discovered_devs);
 166         list_free(ctx->devs);
 167
 168         libusb_exit(ctx->usb_ctx);
 169 #ifdef _WIN32
 170         WSACleanup();
 171 #endif
 172
 173         free(ctx);
 174
 175         return JAYLINK_OK;
 176 }
 177
 178 /**
 179  * Check for a capability of libjaylink.
 180  *
 181  * @param[in] cap Capability to check for.
 182  *
 183  * @retval true Capability is supported.
 184  * @retval false Capability is not supported or invalid argument.
 185  *
 186  * @since 0.1.0
 187  */
 188 JAYLINK_API bool jaylink_library_has_cap(enum jaylink_capability cap)
 189 {
 190         switch (cap) {
 191         case JAYLINK_CAP_HIF_USB:
 192                 return true;
 193         default:
 194                 return false;
 195         }
 196 }