Initial commit

engines/tinsel/token.cpp

@@ -0,0 +1,134 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * To ensure exclusive use of resources and exclusive control responsibilities.
+ */
+
+#include "common/util.h"
+
+#include "tinsel/sched.h"
+#include "tinsel/token.h"
+
+namespace Tinsel {
+
+//----------------- LOCAL GLOBAL DATA --------------------
+
+struct Token {
+	Common::PROCESS		*proc;
+	bool				isFree;
+};
+
+// These vars are reset upon engine destruction
+static Token g_tokens[NUMTOKENS];
+
+
+/**
+ * Release all tokens held by this process, and kill the process.
+ */
+static void TerminateProcess(Common::PROCESS *tProc) {
+
+	// Release tokens held by the process
+	for (int i = 0; i < NUMTOKENS; i++) {
+		if (!g_tokens[i].isFree && g_tokens[i].proc == tProc) {
+			g_tokens[i].proc = nullptr;
+			g_tokens[i].isFree = true;
+		}
+	}
+
+	// Kill the process
+	if (tProc != nullptr)
+		CoroScheduler.killProcess(tProc);
+}
+
+/**
+ * Gain control of the CONTROL token if it is free.
+ */
+void GetControlToken() {
+	const int which = TOKEN_CONTROL;
+
+	if (g_tokens[which].isFree) {
+		g_tokens[which].proc = CoroScheduler.getCurrentProcess();
+		g_tokens[which].isFree = false;
+	}
+}
+
+/**
+ * Release control of the CONTROL token.
+ */
+void FreeControlToken() {
+	// Allow anyone to free TOKEN_CONTROL
+	g_tokens[TOKEN_CONTROL].proc = nullptr;
+	g_tokens[TOKEN_CONTROL].isFree = true;
+}
+
+
+/**
+ * Gain control of a token. If the requested token is out of range, or
+ * is already held by the calling process, then the calling process
+ * will be killed off.
+ *
+ * Otherwise, the calling process will gain the token. If the token was
+ * held by another process, then the previous holder is killed off.
+ */
+void GetToken(int which) {
+	assert(TOKEN_LEAD <= which && which < NUMTOKENS);
+
+	if (!g_tokens[which].isFree) {
+		assert(g_tokens[which].proc != CoroScheduler.getCurrentProcess());
+		TerminateProcess(g_tokens[which].proc);
+	}
+
+	g_tokens[which].proc = CoroScheduler.getCurrentProcess();
+	g_tokens[which].isFree = false;
+}
+
+/**
+ * Release control of a token. If the requested token is not owned by
+ * the calling process, then the calling process will be killed off.
+ */
+void FreeToken(int which) {
+	assert(TOKEN_LEAD <= which && which < NUMTOKENS);
+
+	assert(g_tokens[which].proc == CoroScheduler.getCurrentProcess());	// we'd have been killed if some other proc had taken this token
+
+	g_tokens[which].proc = nullptr;
+	g_tokens[which].isFree = true;
+}
+
+/**
+ * If it's a valid token and it's free, returns true.
+ */
+bool TestToken(int which) {
+	if (which < 0 || which >= NUMTOKENS)
+		return false;
+
+	return (g_tokens[which].isFree);
+}
+
+/**
+ * Call at the start of each scene.
+ */
+void FreeAllTokens() {
+	for (int i = 0; i < NUMTOKENS; i++) {
+		g_tokens[i].proc = nullptr;
+		g_tokens[i].isFree = true;
+	}
+}
+
+} // End of namespace Tinsel