Webclient: Limit max requests to 8 concurrently

src/Http_Web.c

@@ -5,7 +5,7 @@
 #include "Errors.h"
 extern void interop_DownloadAsync(const char* url, int method, int reqID);
 extern int interop_IsHttpsOnly(void);
-static struct RequestList pendingReqs;
+static struct RequestList workingReqs, queuedReqs;
 
 
 /*########################################################################################################################*
@@ -26,18 +26,20 @@ cc_bool Http_GetCurrent(int* reqID, int* progress) {
 }
 
 int Http_CheckProgress(int reqID) {
-	int idx = RequestList_Find(&pendingReqs, reqID);
+	int idx = RequestList_Find(&workingReqs, reqID);
 	if (idx == -1) return HTTP_PROGRESS_NOT_WORKING_ON;
 
-	return pendingReqs.entries[idx].progress;
+	return workingReqs.entries[idx].progress;
 }
 
 void Http_ClearPending(void) {
-	RequestList_Free(&pendingReqs);
+	RequestList_Free(&queuedReqs);
+	RequestList_Free(&workingReqs);
 }
 
 void Http_TryCancel(int reqID) {
-	RequestList_TryFree(&pendingReqs,   reqID);
+	RequestList_TryFree(&queuedReqs,    reqID);
+	RequestList_TryFree(&workingReqs,   reqID);
 	RequestList_TryFree(&processedReqs, reqID);
 }
 
@@ -47,48 +49,63 @@ void Http_TryCancel(int reqID) {
 *#########################################################################################################################*/
 cc_bool Http_DescribeError(cc_result res, cc_string* dst) { return false; }
 
+#define HTTP_MAX_CONCURRENCY 8
+static void Http_StartNextDownload(void) {
+	char urlBuffer[URL_MAX_SIZE]; cc_string url;
+	char urlStr[NATIVE_STR_LEN];
+	struct HttpRequest* req;
+
+	/* Avoid making too many requests at once */
+	if (workingReqs.count >= HTTP_MAX_CONCURRENCY) return;
+	if (!queuedReqs.count) return;
+	String_InitArray(url, urlBuffer);
+
+	req = &queuedReqs.entries[0];
+	Http_GetUrl(req, &url);
+	Platform_Log1("Fetching %s", &url);
+
+	Platform_EncodeUtf8(urlStr, &url);
+	interop_DownloadAsync(urlStr, req->requestType, req->id);
+	RequestList_Append(&workingReqs, req, false);
+	RequestList_RemoveAt(&queuedReqs, 0);
+}
+
 EMSCRIPTEN_KEEPALIVE void Http_OnUpdateProgress(int reqID, int read, int total) {
-	int idx = RequestList_Find(&pendingReqs, reqID);
+	int idx = RequestList_Find(&workingReqs, reqID);
 	if (idx == -1 || !total) return;
 
-	pendingReqs.entries[idx].progress = (int)(100.0f * read / total);
+	workingReqs.entries[idx].progress = (int)(100.0f * read / total);
 }
 
 EMSCRIPTEN_KEEPALIVE void Http_OnFinishedAsync(int reqID, void* data, int len, int status) {
 	struct HttpRequest* req;
-	int idx = RequestList_Find(&pendingReqs, reqID);
+	int idx = RequestList_Find(&workingReqs, reqID);
 
-	/* Shouldn't ever happen, but log a warning anyways */
 	if (idx == -1) {
-		Mem_Free(data); Platform_Log1("Ignoring invalid request (%i)", &reqID); return;
+		/* Shouldn't ever happen, but log a warning anyways */
+		Mem_Free(data); 
+		Platform_Log1("Ignoring invalid request (%i)", &reqID);
+	} else {
+		req = &workingReqs.entries[idx];
+		req->data          = data;
+		req->size          = len;
+		req->statusCode    = status;
+		req->contentLength = len;
+
+		/* Usually this happens when denied by CORS */
+		if (!status && !data) req->result = ERR_DOWNLOAD_INVALID;
+
+		if (req->data) Platform_Log1("HTTP returned data: %i bytes", &req->size);
+		Http_FinishRequest(req);
+		RequestList_RemoveAt(&workingReqs, idx);
 	}
-
+	Http_StartNextDownload();
-	req = &pendingReqs.entries[idx];
-	req->data          = data;
-	req->size          = len;
-	req->statusCode    = status;
-	req->contentLength = len;
-
-	/* Usually this happens when denied by CORS */
-	if (!status && !data) req->result = ERR_DOWNLOAD_INVALID;
-
-	if (req->data) Platform_Log1("HTTP returned data: %i bytes", &req->size);
-	Http_FinishRequest(req);
-	RequestList_RemoveAt(&pendingReqs, idx);
 }
 
 /* Adds a req to the list of pending requests, waking up worker thread if needed */
 static void Http_BackendAdd(struct HttpRequest* req, cc_bool priority) {
-	char urlBuffer[URL_MAX_SIZE]; cc_string url;
+	RequestList_Append(&queuedReqs, req, priority);
-	char urlStr[NATIVE_STR_LEN];
+	Http_StartNextDownload();
-	String_InitArray(url, urlBuffer);
-
-	RequestList_Append(&pendingReqs, req);
-	Http_GetUrl(req, &url);
-	Platform_Log2("Fetching %s (type %b)", &url, &req->requestType);
-
-	Platform_EncodeUtf8(urlStr, &url);
-	interop_DownloadAsync(urlStr, req->requestType, req->id);
 }
 
 
@@ -96,20 +113,19 @@ static void Http_BackendAdd(struct HttpRequest* req, cc_bool priority) {
 *-----------------------------------------------------Http component------------------------------------------------------*
 *#########################################################################################################################*/
 static void OnInit(void) {
-	http_terminate = false;
 	ScheduledTask_Add(30, Http_CleanCacheTask);
 	/* If this webpage is https://, browsers deny any http:// downloading */
 	httpsOnly = interop_IsHttpsOnly();
 
-	RequestList_Init(&pendingReqs);
+	RequestList_Init(&queuedReqs);
+	RequestList_Init(&workingReqs);
 	RequestList_Init(&processedReqs);
 }
 
 static void OnFree(void) {
-	http_terminate = true;
 	Http_ClearPending();
-
+	RequestList_Free(&queuedReqs);
-	RequestList_Free(&pendingReqs);
+	RequestList_Free(&workingReqs);
 	RequestList_Free(&processedReqs);
 }
 

src/Http_Worker.c

@@ -123,11 +123,7 @@ static void Http_SignalWorker(void) { Waitable_Signal(workerWaitable); }
 static void Http_BackendAdd(struct HttpRequest* req, cc_bool priority) {
 	Mutex_Lock(pendingMutex);
 	{	
-		if (priority) {
+		RequestList_Append(&pendingReqs, req, priority);
-			RequestList_Prepend(&pendingReqs, req);
-		} else {
-			RequestList_Append(&pendingReqs,  req);
-		}
 	}
 	Mutex_Unlock(pendingMutex);
 	Http_SignalWorker();

src/_HttpBase.h

@@ -33,21 +33,24 @@ static void RequestList_EnsureSpace(struct RequestList* list) {
 				sizeof(struct HttpRequest), HTTP_DEF_ELEMS, 10);
 }
 
-/* Adds another request to end (for normal priority request) */
+/* Adds a request to the list */
-static void RequestList_Append(struct RequestList* list, struct HttpRequest* item) {
+static void RequestList_Append(struct RequestList* list, struct HttpRequest* item, cc_bool atFront) {
-	RequestList_EnsureSpace(list);
-	list->entries[list->count++] = *item;
-}
-
-/* Inserts a request at start (for high priority request) */
-static void RequestList_Prepend(struct RequestList* list, struct HttpRequest* item) {
 	int i;
 	RequestList_EnsureSpace(list);
-	
+
-	for (i = list->count; i > 0; i--) {
+	if (atFront) {
-		list->entries[i] = list->entries[i - 1];
+		/* Shift all requests right one place */
+		for (i = list->count; i > 0; i--) {
+			list->entries[i] = list->entries[i - 1];
+		}
+		/* Insert new request at start */
+		i = 0;
+	} else {
+		/* Insert new request at end */
+		i = list->count;
 	}
-	list->entries[0] = *item;
+
+	list->entries[i] = *item;
 	list->count++;
 }
 
@@ -174,7 +177,7 @@ static void Http_FinishRequest(struct HttpRequest* req) {
 	Mutex_Lock(processedMutex);
 	{
 		req->timeDownloaded = DateTime_CurrentUTC_MS();
-		RequestList_Append(&processedReqs, req);
+		RequestList_Append(&processedReqs, req, false);
 	}
 	Mutex_Unlock(processedMutex);
 }