fundermental concurrency support for sessions

demo/demo.c

@@ -60,6 +60,7 @@ response_t sessions(ctx_t* ctx) {
 	
 	if (*sessiondata == NULL) {
 		*sessiondata = "Test\n";
+		session_update(ctx);
 	} else {
 		output = *sessiondata;
 	}

src/base_cfloor.c

@@ -15,6 +15,8 @@
 
 struct networkingConfig netConfig;
 
+void session_end(ctx_t*);
+
 static void handler(struct request request, struct response _response) {
 	ctx_t ctx = {
 		method: request.metaData.method,
@@ -24,7 +26,8 @@ static void handler(struct request request, struct response _response) {
 		peerPort: request.peer.port,
 		auth: getAuthData(request.headers),
 		requestHeaders: *request.headers,
-		responseHeaders: headers_create()
+		responseHeaders: headers_create(),
+		session: EMPTY_SESSION_CTX,
 	};
 
 	response_t response = routerHandler(&ctx);
@@ -33,6 +36,7 @@ static void handler(struct request request, struct response _response) {
 	}
 	
 	freeAuthData(ctx.auth);
+	session_end(&ctx);
 	
 	headers_merge(&ctx.responseHeaders, &response.headers);
 

src/base_cgi.c

@@ -96,6 +96,8 @@ const char* or(const char* v1, const char* v2) {
 	}
 }
 
+void session_end(ctx_t*);
+
 int main(int argc, char** argv) {
 	struct headers headers = headers_create();
 	if (setHttpHeaders(&headers)) {
@@ -111,7 +113,8 @@ int main(int argc, char** argv) {
 		peerPort: 0, // TODO 
 		auth: getAuthData(request.headers),
 		requestHeaders: headers,
-		responseHeaders: headers_create()
+		responseHeaders: headers_create(),
+		session: EMPTY_SESSION_CTX,
 	};
 
 	response_t response = routerHandler(&ctx);
@@ -124,6 +127,7 @@ int main(int argc, char** argv) {
 	headers_merge(&ctx.responseHeaders, &response.headers);
 	
 	freeAuthData(ctx.auth);
+	session_end(&ctx);
 
 	printf("Status: %d\n\r", response.status);
 	headers_dump(&ctx.responseHeaders, stdout);

src/request.h

@@ -11,6 +11,14 @@
 
 #define NEXT_RESPONSE_STATUS (0)
 
+struct session_ctx {
+    void* session;
+    time_t accessTime;
+    void* data;
+};
+
+#define EMPTY_SESSION_CTX ((struct session_ctx) {.session = NULL})
+
 typedef struct {
 	method_t method;
 	const char* path;
@@ -20,6 +28,7 @@ typedef struct {
 	struct auth auth;
 	struct headers requestHeaders;
 	struct headers responseHeaders;
+    struct session_ctx session;
 } ctx_t;
 
 typedef struct {

src/sessions.c

@@ -1,10 +1,7 @@
 #include <stdlib.h>
 #include <stdbool.h>
-#include <time.h>
 #include <string.h>
 
-#include <uuid/uuid.h>
-
 #include <pthread.h>
 
 #include <headers.h>
@@ -15,12 +12,15 @@
 
 #include "cookies.h"
 
-static struct session {
+struct session {
 	bool inUse;
 	uuid_t id;
 	time_t lastAccess;
+    time_t lastWrite;
 	void* data;
-}* sessions = NULL;
+};
+
+static struct session* sessions = NULL;
 static size_t sessionno = 0;
 static pthread_mutex_t globalLock = PTHREAD_MUTEX_INITIALIZER;
 
@@ -51,6 +51,7 @@ struct session* newSession(size_t size) {
 				return NULL;
 			}
 			memset(sessions[i].data, 0, size);
+			sessions[i].lastWrite = 0;
 			return &(sessions[i]);
 		}
 	}
@@ -116,6 +117,45 @@ void* _session_start(ctx_t* ctx, const char* cookie, size_t size) {
 	pthread_mutex_unlock(&globalLock);
 	
 	session->lastAccess = time(NULL);
+
+	ctx->session.session = session;
+	ctx->session.accessTime = time(NULL);
+
+	void* requestSessionData = malloc(size);
+	if (requestSessionData == NULL) {
+		return NULL;
+	}
+	memcpy(requestSessionData, session->data, size);
+	ctx->session.data = requestSessionData;
 	
-	return session->data;
+	return requestSessionData;
+}
+
+int _session_update(ctx_t* ctx, size_t size) {
+	struct session_ctx* sessionCtx = &(ctx->session);
+	struct session* session = (struct session*) sessionCtx->session;
+	if (session == NULL) {
+		return ERROR_NO_SESSION;
+	}
+
+	pthread_mutex_lock(&globalLock);
+
+	if (session->lastWrite > sessionCtx->accessTime) {
+		pthread_mutex_unlock(&globalLock);
+		return ERROR_CONCURRENT_SESSION;
+	}
+
+	session->lastWrite = time(NULL);
+	sessionCtx->accessTime = session->lastWrite;
+	memcpy(session->data, sessionCtx->data, size);
+
+	pthread_mutex_unlock(&globalLock);
+
+	return 0;
+}
+
+void session_end(ctx_t* ctx) {
+	if (ctx->session.session != NULL) {
+		free(ctx->session.data);
+	}
 }

src/sessions.h

@@ -1,6 +1,10 @@
 #ifndef SESSIONS_H_
 #define SESSIONS_H_
 
+#include <time.h>
+
+#include <uuid/uuid.h>
+
 #ifndef SESSION_PTR_TYPE
 	#pragma GCC warning "session ptr type not defined"
 	#define SESSION_PTR_TYPE int
@@ -16,8 +20,14 @@
 
 #include "request.h"
 
+#define ERROR_NO_SESSION         (-2)
+#define ERROR_CONCURRENT_SESSION (-1)
+
 void* _session_start(ctx_t*, const char*, size_t);
+int _session_update(ctx_t*, size_t);
+void session_end(ctx_t*);
 
 #define session_start(c) ((SESSION_PTR_TYPE*) _session_start(c, SESSION_COOKIE_NAME, sizeof(SESSION_PTR_TYPE)))
+#define session_update(c) _session_update(c, sizeof(SESSION_PTR_TYPE))
 
 #endif