input_stream: added struct input_plugin

Instead of managing a set of method pointers in each input_stream
struct, move these into the new input_plugin struct.  Each
input_stream has only a pointer to the plugin struct.  Pointers to all
implementations are kept in the array "input_plugins".

src/input_curl.c

@@ -452,7 +452,8 @@ input_curl_seek(struct input_stream *is, mpd_unused long offset,
 	return 0;
 }
 
-bool input_curl_open(struct input_stream *is, char *url)
+static bool
+input_curl_open(struct input_stream *is, const char *url)
 {
 	struct input_curl *c;
 	bool ret;
@@ -483,11 +484,14 @@ bool input_curl_open(struct input_stream *is, char *url)
 		return false;
 	}
 
-	is->seekFunc = input_curl_seek;
-	is->closeFunc = input_curl_close;
-	is->readFunc = input_curl_read;
-	is->atEOFFunc = input_curl_eof;
-	is->bufferFunc = input_curl_buffer;
-
 	return true;
 }
+
+const struct input_plugin input_plugin_curl = {
+	.open = input_curl_open,
+	.close = input_curl_close,
+	.buffer = input_curl_buffer,
+	.read = input_curl_read,
+	.eof = input_curl_eof,
+	.seek = input_curl_seek,
+};

src/input_curl.h

@@ -19,14 +19,10 @@
 #ifndef MPD_INPUT_CURL_H
 #define MPD_INPUT_CURL_H
 
-#include <stdbool.h>
-
-struct input_stream;
+extern const struct input_plugin input_plugin_curl;
 
 void input_curl_global_init(void);
 
 void input_curl_global_finish(void);
 
-bool input_curl_open(struct input_stream *is, char *url);
-
 #endif

src/input_file.c

@@ -21,30 +21,15 @@
 #include "log.h"
 #include "os_compat.h"
 
-static int
-input_file_seek(struct input_stream *is, long offset, int whence);
-
-static size_t
-input_file_read(struct input_stream *is, void *ptr, size_t size);
-
-static int
-input_file_close(struct input_stream *is);
-
-static int
-input_file_eof(struct input_stream *is);
-
-static int
-input_file_buffer(struct input_stream *is);
-
-int
-input_file_open(struct input_stream *is, char *filename)
+static bool
+input_file_open(struct input_stream *is, const char *filename)
 {
 	FILE *fp;
 
 	fp = fopen(filename, "r");
 	if (!fp) {
 		is->error = errno;
-		return -1;
+		return false;
 	}
 
 	is->seekable = 1;
@@ -58,15 +43,9 @@ input_file_open(struct input_stream *is, char *filename)
 #endif
 
 	is->data = fp;
-	is->seekFunc = input_file_seek;
-	is->closeFunc = input_file_close;
-	is->readFunc = input_file_read;
-	is->atEOFFunc = input_file_eof;
-	is->bufferFunc = input_file_buffer;
-
 	is->ready = 1;
 
-	return 0;
+	return true;
 }
 
 static int
@@ -128,3 +107,12 @@ input_file_buffer(mpd_unused struct input_stream *is)
 {
 	return 0;
 }
+
+const struct input_plugin input_plugin_file = {
+	.open = input_file_open,
+	.close = input_file_close,
+	.buffer = input_file_buffer,
+	.read = input_file_read,
+	.eof = input_file_eof,
+	.seek = input_file_seek,
+};

src/input_file.h

@@ -21,7 +21,6 @@
 
 #include "input_stream.h"
 
-int
-input_file_open(struct input_stream *is, char *filename);
+extern const struct input_plugin input_plugin_file;
 
 #endif

src/input_stream.c

@@ -27,6 +27,16 @@
 
 #include <stdlib.h>
 
+static const struct input_plugin *const input_plugins[] = {
+	&input_plugin_file,
+#ifdef HAVE_CURL
+	&input_plugin_curl,
+#endif
+};
+
+static const unsigned num_input_plugins =
+	sizeof(input_plugins) / sizeof(input_plugins[0]);
+
 void input_stream_global_init(void)
 {
 #ifdef HAVE_CURL
@@ -52,26 +62,27 @@ int input_stream_open(struct input_stream *is, char *url)
 	is->meta_name = NULL;
 	is->meta_title = NULL;
 
-	if (input_file_open(is, url) == 0)
-		return 0;
+	for (unsigned i = 0; i < num_input_plugins; ++i) {
+		const struct input_plugin *plugin = input_plugins[i];
 
-#ifdef HAVE_CURL
-	if (input_curl_open(is, url))
-		return 0;
-#endif
+		if (plugin->open(is, url)) {
+			is->plugin = plugin;
+			return 0;
+		}
+	}
 
 	return -1;
 }
 
 int input_stream_seek(struct input_stream *is, long offset, int whence)
 {
-	return is->seekFunc(is, offset, whence);
+	return is->plugin->seek(is, offset, whence);
 }
 
 size_t
 input_stream_read(struct input_stream *is, void *ptr, size_t size)
 {
-	return is->readFunc(is, ptr, size);
+	return is->plugin->read(is, ptr, size);
 }
 
 int input_stream_close(struct input_stream *is)
@@ -83,15 +94,15 @@ int input_stream_close(struct input_stream *is)
 	if (is->meta_title)
 		free(is->meta_title);
 
-	return is->closeFunc(is);
+	return is->plugin->close(is);
 }
 
 int input_stream_eof(struct input_stream *is)
 {
-	return is->atEOFFunc(is);
+	return is->plugin->eof(is);
 }
 
 int input_stream_buffer(struct input_stream *is)
 {
-	return is->bufferFunc(is);
+	return is->plugin->buffer(is);
 }

src/input_stream.h

@@ -20,8 +20,23 @@
 #define INPUT_STREAM_H
 
 #include <stddef.h>
+#include <stdbool.h>
+
+struct input_stream;
+
+struct input_plugin {
+	bool (*open)(struct input_stream *is, const char *url);
+	int (*close)(struct input_stream *is);
+
+	int (*buffer)(struct input_stream *is);
+	size_t (*read)(struct input_stream *is, void *ptr, size_t size);
+	int (*eof)(struct input_stream *is);
+	int (*seek)(struct input_stream *is, long offset, int whence);
+};
 
 struct input_stream {
+	const struct input_plugin *plugin;
+
 	int ready;
 
 	int error;
@@ -30,12 +45,6 @@ struct input_stream {
 	char *mime;
 	int seekable;
 
-	int (*seekFunc)(struct input_stream *is, long offset, int whence);
-	size_t (*readFunc)(struct input_stream *is, void *ptr, size_t size);
-	int (*closeFunc)(struct input_stream *is);
-	int (*atEOFFunc)(struct input_stream *is);
-	int (*bufferFunc)(struct input_stream *is);
-
 	void *data;
 	char *meta_name;
 	char *meta_title;