vlib/io: fix reader bugs, make read_all take a config struct (#7361)

vlib/io/reader.v

@@ -4,30 +4,58 @@ module io
 pub interface Reader {
 	// read reads up to buf.len bytes and places
 	// them into buf.
-	// A struct that implements this should return 
+	// A type that implements this should return
 	// `none` on end of stream (EOF) instead of just returning 0
 	read(mut buf []byte) ?int
 }
 
-// make_reader is a temp that converts a struct to a reader
+// make_reader is a temp that converts a type to a reader
 // (e.g. for use in struct initialisation)
+// (this shouldnt need to be a thing but until coercion gets made better
+// it is required)
 pub fn make_reader(r Reader) Reader {
 	return r
 }
 
-pub const (
-	eof_code = -1
-	eof = error_with_code('EOF', eof_code)
-)
-
 const (
 	read_all_len      = 10 * 1024
 	read_all_grow_len = 1024
 )
 
-// read_all reads all available bytes from a reader
-pub fn read_all(r Reader) ?[]byte {
-	mut b := []byte{len:read_all_len}
+// ReadAllConfig allows options to be passed for the behaviour
+// of read_all
+pub struct ReadAllConfig {
+	reader Reader
+	read_to_end_of_stream bool
+}
+
+// read_all reads all bytes from a reader until either a 0 length read
+// or if read_to_end_of_stream is true then the end of the stream (`none`)
+pub fn read_all(config ReadAllConfig) ?[]byte {
+	r := config.reader
+	read_till_eof := config.read_to_end_of_stream
+
+	mut b := []byte{len: read_all_len}
+	mut read := 0
+	for {
+		new_read := r.read(mut b[read..]) or {
+			break
+		}
+		read += new_read
+		if !read_till_eof && read == 0 {
+			break
+		}
+		if b.len == read {
+			b.grow_len(read_all_grow_len)
+		}
+	}
+	return b[..read]
+}
+
+// read_any reads any available bytes from a reader
+// (until the reader returns a read of 0 length)
+pub fn read_any(r Reader) ?[]byte {
+	mut b := []byte{len: read_all_len}
 	mut read := 0
 	for {
 		new_read := r.read(mut b[read..]) or {
@@ -38,7 +66,7 @@ pub fn read_all(r Reader) ?[]byte {
 			break
 		}
 		if b.len == read {
-			b.grow(read_all_grow_len)
+			b.grow_len(read_all_grow_len)
 		}
 	}
 	return b[..read]