Idle: error out when unrecognized idle event was specified

NEWS

@@ -4,6 +4,7 @@ ver 0.19 (not yet released)
   - "lsinfo" and "readcomments" allowed for remote files
   - "listneighbors" lists file servers on the local network
   - "playlistadd" supports file:///
+  - "idle" with unrecognized event name fails
 * database
   - proxy: forward "idle" events
   - proxy: copy "Last-Modified" from remote directories

src/Idle.cxx

@@ -25,6 +25,7 @@
 #include "config.h"
 #include "Idle.hxx"
 #include "GlobalEvents.hxx"
+#include "util/ASCII.hxx"
 
 #include <atomic>
 
@@ -70,3 +71,15 @@ idle_get_names(void)
 {
         return idle_names;
 }
+
+unsigned
+idle_parse_name(const char *name)
+{
+	assert(name != nullptr);
+
+	for (unsigned i = 0; idle_names[i] != nullptr; ++i)
+		if (StringEqualsCaseASCII(name, idle_names[i]))
+			return 1 << i;
+
+	return 0;
+}

src/Idle.hxx

@@ -25,6 +25,8 @@
 #ifndef MPD_IDLE_HXX
 #define MPD_IDLE_HXX
 
+#include "Compiler.h"
+
 /** song database has been updated*/
 static constexpr unsigned IDLE_DATABASE = 0x1;
 
@@ -81,4 +83,12 @@ idle_get(void);
 const char*const*
 idle_get_names(void);
 
+/**
+ * Parse an idle name and return its mask.  Returns 0 if the given
+ * name is unknown.
+ */
+gcc_nonnull_all gcc_pure
+unsigned
+idle_parse_name(const char *name);
+
 #endif

src/command/OtherCommands.cxx

@@ -33,7 +33,6 @@
 #include "protocol/Result.hxx"
 #include "ls.hxx"
 #include "mixer/Volume.hxx"
-#include "util/ASCII.hxx"
 #include "util/UriUtil.hxx"
 #include "util/Error.hxx"
 #include "fs/AllocatedPath.hxx"
@@ -363,17 +362,19 @@ CommandResult
 handle_idle(Client &client,
 	    gcc_unused int argc, gcc_unused char *argv[])
 {
-	unsigned flags = 0, j;
+	unsigned flags = 0;
 	int i;
-	const char *const* idle_names;
 
-	idle_names = idle_get_names();
 	for (i = 1; i < argc; ++i) {
-		for (j = 0; idle_names[j]; ++j) {
-			if (StringEqualsCaseASCII(argv[i], idle_names[j])) {
-				flags |= (1 << j);
-			}
+		unsigned event = idle_parse_name(argv[i]);
+		if (event == 0) {
+			command_error(client, ACK_ERROR_ARG,
+				      "Unrecognized idle event: %s",
+				      argv[i]);
+			return CommandResult::ERROR;
 		}
+
+		flags |= event;
 	}
 
 	/* No argument means that the client wants to receive everything */