GUAC-236: Handle specific instructions via an opcode/handler mapping.

src/guacenc/Makefile.am

@@ -24,13 +24,15 @@ AUTOMAKE_OPTIONS = foreign
 
 bin_PROGRAMS = guacenc
 
-noinst_HEADERS =  \
-    encode.h      \
+noinst_HEADERS =   \
+    encode.h       \
+    instructions.h \
     log.h
 
-guacenc_SOURCES = \
-    encode.c      \
-    guacenc.c     \
+guacenc_SOURCES =  \
+    encode.c       \
+    guacenc.c      \
+    instructions.c \
     log.c
 
 guacenc_CFLAGS =            \

src/guacenc/encode.c

@@ -21,6 +21,7 @@
  */
 
 #include "config.h"
+#include "instructions.h"
 #include "log.h"
 
 #include <guacamole/client.h>
@@ -57,12 +58,10 @@ static int guacenc_read_instructions(const char* path, guac_socket* socket) {
     if (parser == NULL)
         return 1;
 
-    /* Continuously read instructions */
+    /* Continuously read and handle all instructions */
     while (!guac_parser_read(parser, socket, -1)) {
-
-        /* STUB: Handle instruction */
-        guacenc_log(GUAC_LOG_DEBUG, "STUB: \"%s\" ...", parser->opcode);
-
+        guacenc_handle_instruction(parser->opcode, parser->argc,
+                (const char**) parser->argv);
     }
 
     /* Fail on read/parse error */

src/guacenc/instructions.c

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2016 Glyptodon, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "config.h"
+#include "instructions.h"
+#include "log.h"
+
+#include <guacamole/client.h>
+
+#include <string.h>
+
+guacenc_instruction_handler_mapping guacenc_instruction_handler_map[] = {
+    {"blob",     NULL},
+    {"img",      NULL},
+    {"end",      NULL},
+    {"cursor",   NULL},
+    {"copy",     NULL},
+    {"transfer", NULL},
+    {"size",     NULL},
+    {"rect",     NULL},
+    {"cfill",    NULL},
+    {"move",     NULL},
+    {"shade",    NULL},
+    {"dispose",  NULL},
+    {NULL,       NULL}
+};
+
+int guacenc_handle_instruction(const char* opcode,
+        int argc, const char** argv) {
+
+    /* Search through mapping for instruction handler having given opcode */
+    guacenc_instruction_handler_mapping* current = guacenc_instruction_handler_map;
+    while (current->opcode != NULL) {
+
+        /* Invoke handler if opcode matches (if defined) */
+        if (strcmp(current->opcode, opcode) == 0) {
+
+            /* Invoke defined handler */
+            guacenc_instruction_handler* handler = current->handler;
+            if (handler != NULL)
+                return handler(argc, argv);
+
+            /* Log defined but unimplemented instructions */
+            guacenc_log(GUAC_LOG_DEBUG, "\"%s\" not implemented", opcode);
+            return 0;
+
+        }
+
+        /* Next candidate handler */
+        current++;
+
+    } /* end opcode search */
+
+    /* Ignore any unknown instructions */
+    return 0;
+
+}
+

src/guacenc/instructions.h

@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2016 Glyptodon, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef GUACENC_INSTRUCTIONS_H
+#define GUACENC_INSTRUCTIONS_H
+
+#include "config.h"
+
+/**
+ * A callback function which, when invoked, handles a particular Guacamole
+ * instruction. The opcode of the instruction is implied (as it is expected
+ * that there will be a 1:1 mapping of opcode to callback function), while the
+ * arguments for that instruction are included in the parameters given to the
+ * callback.
+ *
+ * @param argc
+ *     The number of arguments (excluding opcode) passed to the instruction
+ *     being handled by the callback.
+ *
+ * @param argv
+ *     All arguments (excluding opcode) associated with the instruction being
+ *     handled by the callback.
+ *
+ * @return
+ *     Zero if the instruction was handled successfully, non-zero if an error
+ *     occurs.
+ */
+typedef int guacenc_instruction_handler(int argc, const char** argv);
+
+/**
+ * Mapping of instruction opcode to corresponding handler function.
+ */
+typedef struct guacenc_instruction_handler_mapping {
+
+    /**
+     * The opcode of the instruction that the associated handler function
+     * should be invoked for.
+     */
+    const char* opcode;
+
+    /**
+     * The handler function to invoke whenever an instruction having the
+     * associated opcode is parsed.
+     */
+    guacenc_instruction_handler* handler;
+
+} guacenc_instruction_handler_mapping;
+
+/**
+ * Array of all opcode/handler mappings for all supported opcodes, terminated
+ * by an entry with a NULL opcode. All opcodes not listed here can be safely
+ * ignored.
+ */
+extern guacenc_instruction_handler_mapping guacenc_instruction_handler_map[];
+
+/**
+ * Handles the instruction having the given opcode and arguments, encoding the
+ * result to the in-progress video.
+ *
+ * @param opcode
+ *     The opcode of the instruction being handled.
+ *
+ * @param argc
+ *     The number of arguments (excluding opcode) passed to the instruction
+ *     being handled by the callback.
+ *
+ * @param argv
+ *     All arguments (excluding opcode) associated with the instruction being
+ *     handled by the callback.
+ *
+ * @return
+ *     Zero if the instruction was handled successfully, non-zero if an error
+ *     occurs.
+ */
+int guacenc_handle_instruction(const char* opcode, int argc,
+        const char** argv);
+
+#endif
+