Move document indicator detection to Input.

parser/src/input.rs

@@ -1,3 +1,5 @@
+use crate::char_traits::is_blank_or_breakz;
+
 /// Interface for a source of characters.
 ///
 /// Hiding the input's implementation behind this trait allows mostly:
@@ -104,7 +106,7 @@ pub trait Input {
 
     /// Return whether the next 2 characters in the input source match the given characters.
     ///
-    /// This function assumes that the next 2 characters in the input has already been fetched
+    /// This function assumes that the next 2 characters in the input have already been fetched
     /// through [`Input::lookahead`].
     #[inline]
     #[must_use]
@@ -115,7 +117,7 @@ pub trait Input {
 
     /// Return whether the next 3 characters in the input source match the given characters.
     ///
-    /// This function assumes that the next 3 characters in the input has already been fetched
+    /// This function assumes that the next 3 characters in the input have already been fetched
     /// through [`Input::lookahead`].
     #[inline]
     #[must_use]
@@ -123,4 +125,38 @@ pub trait Input {
         assert!(self.buflen() >= 3);
         self.peek() == c1 && self.peek_nth(1) == c2 && self.peek_nth(2) == c3
     }
+
+    /// Check whether the next characters correspond to a document indicator.
+    ///
+    /// This function assumes that the next 4 characters in the input has already been fetched
+    /// through [`Input::lookahead`].
+    #[inline]
+    #[must_use]
+    fn next_is_document_indicator(&self) -> bool {
+        assert!(self.buflen() >= 4);
+        is_blank_or_breakz(self.peek_nth(3))
+            && (self.next_3_are('.', '.', '.') || self.next_3_are('-', '-', '-'))
+    }
+
+    /// Check whether the next characters correspond to a start of document.
+    ///
+    /// This function assumes that the next 4 characters in the input has already been fetched
+    /// through [`Input::lookahead`].
+    #[inline]
+    #[must_use]
+    fn next_is_document_start(&self) -> bool {
+        assert!(self.buflen() >= 4);
+        self.next_3_are('-', '-', '-') && is_blank_or_breakz(self.peek_nth(3))
+    }
+
+    /// Check whether the next characters correspond to an end of document.
+    ///
+    /// This function assumes that the next 4 characters in the input has already been fetched
+    /// through [`Input::lookahead`].
+    #[inline]
+    #[must_use]
+    fn next_is_document_end(&self) -> bool {
+        assert!(self.buflen() >= 4);
+        self.next_3_are('.', '.', '.') && is_blank_or_breakz(self.peek_nth(3))
+    }
 }

parser/src/scanner.rs

@@ -575,32 +575,6 @@ impl<T: Input> Scanner<T> {
         s.push('\n');
     }
 
-    /// Check whether the next characters correspond to a start of document.
-    ///
-    /// [`Self::lookahead`] must have been called before calling this function.
-    fn next_is_document_start(&self) -> bool {
-        assert!(self.input.buflen() >= 4);
-        self.input.next_3_are('-', '-', '-') && is_blank_or_breakz(self.input.peek_nth(3))
-    }
-
-    /// Check whether the next characters correspond to an end of document.
-    ///
-    /// [`Self::lookahead`] must have been called before calling this function.
-    fn next_is_document_end(&self) -> bool {
-        assert!(self.input.buflen() >= 4);
-        self.input.next_3_are('.', '.', '.') && is_blank_or_breakz(self.input.peek_nth(3))
-    }
-
-    /// Check whether the next characters correspond to a document indicator.
-    ///
-    /// [`Self::lookahead`] must have been called before calling this function.
-    #[inline]
-    fn next_is_document_indicator(&self) -> bool {
-        assert!(self.input.buflen() >= 4);
-        is_blank_or_breakz(self.input.peek_nth(3))
-            && (self.input.next_3_are('.', '.', '.') || self.input.next_3_are('-', '-', '-'))
-    }
-
     /// Insert a token at the given position.
     fn insert_token(&mut self, pos: usize, tok: Token) {
         let old_len = self.tokens.len();
@@ -650,9 +624,9 @@ impl<T: Input> Scanner<T> {
         if self.mark.col == 0 {
             if self.input.next_char_is('%') {
                 return self.fetch_directive();
-            } else if self.next_is_document_start() {
+            } else if self.input.next_is_document_start() {
                 return self.fetch_document_indicator(TokenType::DocumentStart);
-            } else if self.next_is_document_end() {
+            } else if self.input.next_is_document_end() {
                 self.fetch_document_indicator(TokenType::DocumentEnd)?;
                 self.skip_ws_to_eol(SkipTabs::Yes)?;
                 if !is_breakz(self.input.peek()) {
@@ -1667,7 +1641,7 @@ impl<T: Input> Scanner<T> {
         while self.mark.col == indent && !is_z(self.input.peek()) {
             if indent == 0 {
                 self.input.lookahead(4);
-                if self.next_is_document_end() {
+                if self.input.next_is_document_end() {
                     break;
                 }
             }
@@ -1885,7 +1859,7 @@ impl<T: Input> Scanner<T> {
             /* Check for a document indicator. */
             self.input.lookahead(4);
 
-            if self.mark.col == 0 && self.next_is_document_indicator() {
+            if self.mark.col == 0 && self.input.next_is_document_indicator() {
                 return Err(ScanError::new_str(
                     start_mark,
                     "while scanning a quoted scalar, found unexpected document indicator",
@@ -2159,7 +2133,7 @@ impl<T: Input> Scanner<T> {
 
         loop {
             self.input.lookahead(4);
-            if self.next_is_document_indicator() || self.input.peek() == '#' {
+            if self.input.next_is_document_indicator() || self.input.peek() == '#' {
                 break;
             }