Introduce object for tokens

[src/app-framework-binder.git] / src / afb-token.c

diff --git a/src/afb-token.c b/src/afb-token.c
new file mode 100644 (file)
index 0000000..b81a87d
--- /dev/null
+++ b/src/afb-token.c
@@ -0,0 +1,182 @@
+/*
+ * Copyright (C) 2015-2019 "IoT.bzh"
+ * Author "Fulup Ar Foll"
+ * Author: José Bollo <jose.bollo@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <pthread.h>
+#include <errno.h>
+
+#include "afb-token.h"
+
+/**
+ * structure for recording a token
+ */
+struct afb_token
+{
+       /** link to the next token of the list */
+       struct afb_token *next;
+
+       /** reference of the token */
+       uint16_t refcount;
+
+       /** local numeric id of the token */
+       uint16_t id;
+
+       /** string value of the token */
+       char text[];
+};
+
+struct tokenset
+{
+       struct afb_token *first;
+       pthread_mutex_t mutex;
+       uint16_t idgen;
+};
+
+static struct tokenset tokenset = {
+       .first = 0,
+       .mutex = PTHREAD_MUTEX_INITIALIZER,
+       .idgen = 0
+};
+
+static struct afb_token *searchid(uint16_t id)
+{
+       struct afb_token *r = tokenset.first;
+       while (r && r->id != id)
+               r = r->next;
+       return r;
+}
+
+/**
+ * Get a token for the given value
+ *
+ * @param token address to return the pointer to the gotten token
+ * @param tokenstring string value of the token to get
+ * @return 0 in case of success or a -errno like negative code
+ */
+int afb_token_get(struct afb_token **token, const char *tokenstring)
+{
+       int rc;
+       struct afb_token *tok;
+       size_t length;
+
+       /* get length of the token string */
+       length =  + strlen(tokenstring);
+
+       /* concurrency */
+       pthread_mutex_lock(&tokenset.mutex);
+
+       /* search the token */
+       tok = tokenset.first;
+       while (tok && memcmp(tokenstring, tok->text, length))
+               tok = tok->next;
+
+       /* search done */
+       if (tok) {
+               /* found */
+               tok = afb_token_addref(tok);
+               rc = 0;
+       } else {
+               /* not found, create */
+               tok = malloc(length + sizeof *tok);
+               if (!tok)
+                       /* creation failed */
+                       rc = -ENOMEM;
+               else {
+                       while(!++tokenset.idgen || searchid(tokenset.idgen));
+                       tok->next = tokenset.first;
+                       tokenset.first = tok;
+                       tok->id = tokenset.idgen;
+                       tok->refcount = 1;
+                       memcpy(tok->text, tokenstring, length);
+                       rc = 0;
+               }
+       }
+       pthread_mutex_unlock(&tokenset.mutex);
+       *token = tok;
+       return rc;
+}
+
+/**
+ * Add a reference count to the given token
+ *
+ * @param token the token to reference
+ * @return the token with the reference added
+ */
+struct afb_token *afb_token_addref(struct afb_token *token)
+{
+       if (token)
+               __atomic_add_fetch(&token->refcount, 1, __ATOMIC_RELAXED);
+       return token;
+}
+
+/**
+ * Remove a reference to the given token and clean the memory if needed
+ *
+ * @param token the token that is unreferenced
+ */
+void afb_token_unref(struct afb_token *token)
+{
+       struct afb_token **pt;
+       if (token && !__atomic_sub_fetch(&token->refcount, 1, __ATOMIC_RELAXED)) {
+               pthread_mutex_lock(&tokenset.mutex);
+               pt = &tokenset.first;
+               while (*pt && *pt != token)
+               if (*pt)
+                       *pt = token->next;
+               pthread_mutex_unlock(&tokenset.mutex);
+               free(token);
+       }
+}
+
+/**
+ * Check whether the token is valid or not
+ *
+ * @param token the token to check
+ * @return a boolean value: 0 if not valid, 1 if valid
+ */
+int afb_token_check(struct afb_token *token)
+{
+       /* TODO */
+       return 1;
+}
+
+/**
+ * Get the string value of the token
+ *
+ * @param token the token whose string value is queried
+ * @return the string value of the token
+ */
+const char *afb_token_string(const struct afb_token *token)
+{
+       return token->text;
+}
+
+/**
+ * Get the "local" numeric id of the token
+ *
+ * @param token the token whose id is queried
+ * @return the numeric id of the token
+ */
+uint16_t afb_token_id(const struct afb_token *token)
+{
+       return token->id;
+}