Move pp::Printer out field to owned String

This enforces that eof() must be called to get the String out, and
generally is better from an API perspective. No users of pretty printing
pre-allocate the buffer.

diff --git a/src/librustc/hir/print.rs b/src/librustc/hir/print.rs
index 01cdd8a6f22bb1b6bc20acc1ab69b91b0ccf849d..8342331e36099241e30798c16e65a9cd2582363e 100644 (file)
--- a/src/librustc/hir/print.rs
+++ b/src/librustc/hir/print.rs
@@ -68,13 +68,13 @@ fn nested(&self, state: &mut State<'_>, nested: Nested) {
 }
 
 pub struct State<'a> {
-    pub s: pp::Printer<'a>,
+    pub s: pp::Printer,
     comments: Option<Comments<'a>>,
     ann: &'a (dyn PpAnn + 'a),
 }
 
 impl<'a> PrintState<'a> for State<'a> {
-    fn writer(&mut self) -> &mut pp::Printer<'a> {
+    fn writer(&mut self) -> &mut pp::Printer {
         &mut self.s
     }
 
@@ -94,16 +94,14 @@ pub fn print_crate<'a>(cm: &'a SourceMap,
                        filename: FileName,
                        input: String,
                        ann: &'a dyn PpAnn) -> String {
-    let mut out = String::new();
-    let mut s = State::new_from_input(cm, sess, filename, input, &mut out, ann);
+    let mut s = State::new_from_input(cm, sess, filename, input, ann);
 
     // When printing the AST, we sometimes need to inject `#[no_std]` here.
     // Since you can't compile the HIR, it's not necessary.
 
     s.print_mod(&krate.module, &krate.attrs);
     s.print_remaining_comments();
-    s.s.eof();
-    out
+    s.s.eof()
 }
 
 impl<'a> State<'a> {
@@ -111,11 +109,10 @@ pub fn new_from_input(cm: &'a SourceMap,
                           sess: &ParseSess,
                           filename: FileName,
                           input: String,
-                          out: &'a mut String,
                           ann: &'a dyn PpAnn)
                           -> State<'a> {
         State {
-            s: pp::mk_printer(out),
+            s: pp::mk_printer(),
             comments: Some(Comments::new(cm, sess, filename, input)),
             ann,
         }
@@ -125,17 +122,13 @@ pub fn new_from_input(cm: &'a SourceMap,
 pub fn to_string<F>(ann: &dyn PpAnn, f: F) -> String
     where F: FnOnce(&mut State<'_>)
 {
-    let mut wr = String::new();
-    {
-        let mut printer = State {
-            s: pp::mk_printer(&mut wr),
-            comments: None,
-            ann,
-        };
-        f(&mut printer);
-        printer.s.eof();
-    }
-    wr
+    let mut printer = State {
+        s: pp::mk_printer(),
+        comments: None,
+        ann,
+    };
+    f(&mut printer);
+    printer.s.eof()
 }
 
 pub fn visibility_qualified<S: Into<Cow<'static, str>>>(vis: &hir::Visibility, w: S) -> String {

diff --git a/src/librustc_driver/pretty.rs b/src/librustc_driver/pretty.rs
index 3e6d843ffbe3104ceb1ee696029931f9aa018336..cd38eb695eb5dfbde67c61d8143fed13aa5b7759 100644 (file)
--- a/src/librustc_driver/pretty.rs
+++ b/src/librustc_driver/pretty.rs
@@ -814,7 +814,6 @@ pub fn print_after_hir_lowering<'tcx>(
                                                                          &sess.parse_sess,
                                                                          src_name,
                                                                          src,
-                                                                         out,
                                                                          annotation.pp_ann());
                     for node_id in uii.all_matching_node_ids(hir_map) {
                         let hir_id = tcx.hir().node_to_hir_id(node_id);
@@ -826,7 +825,7 @@ pub fn print_after_hir_lowering<'tcx>(
                         pp_state.synth_comment(path);
                         pp_state.s.hardbreak();
                     }
-                    pp_state.s.eof();
+                    *out = pp_state.s.eof();
                 })
             }
 

diff --git a/src/libsyntax/print/pp.rs b/src/libsyntax/print/pp.rs
index f64e95aee5bca91ee5ac4382bdf997db165a519e..ea90defcd508c10809dd9b84d6f2b8a27c4a7b66 100644 (file)
--- a/src/libsyntax/print/pp.rs
+++ b/src/libsyntax/print/pp.rs
@@ -235,13 +235,13 @@ fn buf_str(buf: &[BufEntry], left: usize, right: usize, lim: usize) -> String {
 
 const SIZE_INFINITY: isize = 0xffff;
 
-pub fn mk_printer(out: &mut String) -> Printer<'_> {
+pub fn mk_printer() -> Printer {
     let linewidth = 78;
     // Yes 55, it makes the ring buffers big enough to never fall behind.
     let n: usize = 55 * linewidth;
     debug!("mk_printer {}", linewidth);
     Printer {
-        out,
+        out: String::new(),
         buf_max_len: n,
         margin: linewidth as isize,
         space: linewidth as isize,
@@ -258,8 +258,8 @@ pub fn mk_printer(out: &mut String) -> Printer<'_> {
     }
 }
 
-pub struct Printer<'a> {
-    out: &'a mut String,
+pub struct Printer {
+    out: String,
     buf_max_len: usize,
     /// Width of lines we're constrained to
     margin: isize,
@@ -300,7 +300,7 @@ fn default() -> Self {
     }
 }
 
-impl<'a> Printer<'a> {
+impl Printer {
     pub fn last_token(&mut self) -> Token {
         self.buf[self.right].token.clone()
     }
@@ -629,8 +629,9 @@ pub fn break_offset(&mut self, n: usize, off: isize) {
         self.pretty_print_end()
     }
 
-    pub fn eof(&mut self) {
-        self.pretty_print_eof()
+    pub fn eof(mut self) -> String {
+        self.pretty_print_eof();
+        self.out
     }
 
     pub fn word<S: Into<Cow<'static, str>>>(&mut self, wrd: S) {

diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 43714d3015bed66155c530eb0438a976f3d6e2c8..54672d9da2e2b8ffffc70366b2befa89b597176d 100644 (file)
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -87,7 +87,7 @@ pub fn trailing_comment(
 }
 
 pub struct State<'a> {
-    pub s: pp::Printer<'a>,
+    pub s: pp::Printer,
     comments: Option<Comments<'a>>,
     ann: &'a (dyn PpAnn+'a),
     is_expanded: bool
@@ -104,9 +104,8 @@ pub fn print_crate<'a>(cm: &'a SourceMap,
                        input: String,
                        ann: &'a dyn PpAnn,
                        is_expanded: bool) -> String {
-    let mut out = String::new();
     let mut s = State {
-        s: pp::mk_printer(&mut out),
+        s: pp::mk_printer(),
         comments: Some(Comments::new(cm, sess, filename, input)),
         ann,
         is_expanded,
@@ -133,25 +132,20 @@ pub fn print_crate<'a>(cm: &'a SourceMap,
 
     s.print_mod(&krate.module, &krate.attrs);
     s.print_remaining_comments();
-    s.s.eof();
-    out
+    s.s.eof()
 }
 
 pub fn to_string<F>(f: F) -> String where
     F: FnOnce(&mut State<'_>),
 {
-    let mut wr = String::new();
-    {
-        let mut printer = State {
-            s: pp::mk_printer(&mut wr),
-            comments: None,
-            ann: &NoAnn,
-            is_expanded: false
-        };
-        f(&mut printer);
-        printer.s.eof();
-    }
-    wr
+    let mut printer = State {
+        s: pp::mk_printer(),
+        comments: None,
+        ann: &NoAnn,
+        is_expanded: false
+    };
+    f(&mut printer);
+    printer.s.eof()
 }
 
 fn binop_to_string(op: BinOpToken) -> &'static str {
@@ -439,7 +433,7 @@ fn visibility_qualified(vis: &ast::Visibility, s: &str) -> String {
 }
 
 pub trait PrintState<'a> {
-    fn writer(&mut self) -> &mut pp::Printer<'a>;
+    fn writer(&mut self) -> &mut pp::Printer;
     fn comments(&mut self) -> &mut Option<Comments<'a>>;
 
     fn word_space<S: Into<Cow<'static, str>>>(&mut self, w: S) {
@@ -760,7 +754,7 @@ fn nbsp(&mut self) { self.writer().word(" ") }
 }
 
 impl<'a> PrintState<'a> for State<'a> {
-    fn writer(&mut self) -> &mut pp::Printer<'a> {
+    fn writer(&mut self) -> &mut pp::Printer {
         &mut self.s
     }