auto merge of #15493 : brson/rust/tostr, r=pcwalton

This updates https://github.com/rust-lang/rust/pull/15075.

Rename `ToStr::to_str` to `ToString::to_string`. The naive renaming ends up with two `to_string` functions defined on strings in the prelude (the other defined via `collections::str::StrAllocating`). To remedy this I removed `StrAllocating::to_string`, making all conversions from `&str` to `String` go through `Show`. This has a measurable impact on the speed of this conversion, but the sense I get from others is that it's best to go ahead and unify `to_string` and address performance for all `to_string` conversions in `core::fmt`. `String::from_str(...)` still works as a manual fast-path.

Note that the patch was done with a script, and ended up renaming a number of other `*_to_str` functions, particularly inside of rustc. All the ones I saw looked correct, and I didn't notice any additional API breakage.

Closes #15046.

1 files changed, 160 insertions, 20 deletions

diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index cdaa9bbd8dd..e695241472b 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -128,6 +128,126 @@ pub fn print_crate<'a>(cm: &'a CodeMap,
     eof(&mut s.s)
 }
 
+pub fn to_string(f: |&mut State| -> IoResult<()>) -> String {
+    let mut s = rust_printer(box MemWriter::new());
+    f(&mut s).unwrap();
+    eof(&mut s.s).unwrap();
+    unsafe {
+        // FIXME(pcwalton): A nasty function to extract the string from an `io::Writer`
+        // that we "know" to be a `MemWriter` that works around the lack of checked
+        // downcasts.
+        let (_, wr): (uint, Box<MemWriter>) = mem::transmute_copy(&s.s.out);
+        let result =
+            str::from_utf8_owned(Vec::from_slice(wr.get_ref())).unwrap();
+        mem::forget(wr);
+        result.to_string()
+    }
+}
+
+pub fn ty_to_string(ty: &ast::Ty) -> String {
+    to_string(|s| s.print_type(ty))
+}
+
+pub fn pat_to_string(pat: &ast::Pat) -> String {
+    to_string(|s| s.print_pat(pat))
+}
+
+pub fn expr_to_string(e: &ast::Expr) -> String {
+    to_string(|s| s.print_expr(e))
+}
+
+pub fn lifetime_to_string(e: &ast::Lifetime) -> String {
+    to_string(|s| s.print_lifetime(e))
+}
+
+pub fn tt_to_string(tt: &ast::TokenTree) -> String {
+    to_string(|s| s.print_tt(tt))
+}
+
+pub fn tts_to_string(tts: &[ast::TokenTree]) -> String {
+    to_string(|s| s.print_tts(tts))
+}
+
+pub fn stmt_to_string(stmt: &ast::Stmt) -> String {
+    to_string(|s| s.print_stmt(stmt))
+}
+
+pub fn item_to_string(i: &ast::Item) -> String {
+    to_string(|s| s.print_item(i))
+}
+
+pub fn generics_to_string(generics: &ast::Generics) -> String {
+    to_string(|s| s.print_generics(generics))
+}
+
+pub fn ty_method_to_string(p: &ast::TypeMethod) -> String {
+    to_string(|s| s.print_ty_method(p))
+}
+
+pub fn method_to_string(p: &ast::Method) -> String {
+    to_string(|s| s.print_method(p))
+}
+
+pub fn fn_block_to_string(p: &ast::FnDecl) -> String {
+    to_string(|s| s.print_fn_block_args(p))
+}
+
+pub fn path_to_string(p: &ast::Path) -> String {
+    to_string(|s| s.print_path(p, false))
+}
+
+pub fn ident_to_string(id: &ast::Ident) -> String {
+    to_string(|s| s.print_ident(*id))
+}
+
+pub fn fun_to_string(decl: &ast::FnDecl, fn_style: ast::FnStyle, name: ast::Ident,
+                  opt_explicit_self: Option<ast::ExplicitSelf_>,
+                  generics: &ast::Generics) -> String {
+    to_string(|s| {
+        try!(s.print_fn(decl, Some(fn_style), abi::Rust,
+                        name, generics, opt_explicit_self, ast::Inherited));
+        try!(s.end()); // Close the head box
+        s.end() // Close the outer box
+    })
+}
+
+pub fn block_to_string(blk: &ast::Block) -> String {
+    to_string(|s| {
+        // containing cbox, will be closed by print-block at }
+        try!(s.cbox(indent_unit));
+        // head-ibox, will be closed by print-block after {
+        try!(s.ibox(0u));
+        s.print_block(blk)
+    })
+}
+
+pub fn meta_item_to_string(mi: &ast::MetaItem) -> String {
+    to_string(|s| s.print_meta_item(mi))
+}
+
+pub fn attribute_to_string(attr: &ast::Attribute) -> String {
+    to_string(|s| s.print_attribute(attr))
+}
+
+pub fn lit_to_string(l: &ast::Lit) -> String {
+    to_string(|s| s.print_literal(l))
+}
+
+pub fn explicit_self_to_string(explicit_self: ast::ExplicitSelf_) -> String {
+    to_string(|s| s.print_explicit_self(explicit_self, ast::MutImmutable).map(|_| {}))
+}
+
+pub fn variant_to_string(var: &ast::Variant) -> String {
+    to_string(|s| s.print_variant(var))
+}
+
+pub fn arg_to_string(arg: &ast::Arg) -> String {
+    to_string(|s| s.print_arg(arg))
+}
+
+
+
+#[cfg(stage0)]
 pub fn to_str(f: |&mut State| -> IoResult<()>) -> String {
     let mut s = rust_printer(box MemWriter::new());
     f(&mut s).unwrap();
@@ -144,62 +264,72 @@ pub fn to_str(f: |&mut State| -> IoResult<()>) -> String {
     }
 }
 
+#[cfg(stage0)]
 pub fn ty_to_str(ty: &ast::Ty) -> String {
     to_str(|s| s.print_type(ty))
 }
 
+#[cfg(stage0)]
 pub fn pat_to_str(pat: &ast::Pat) -> String {
     to_str(|s| s.print_pat(pat))
 }
 
+#[cfg(stage0)]
 pub fn expr_to_str(e: &ast::Expr) -> String {
     to_str(|s| s.print_expr(e))
 }
 
+#[cfg(stage0)]
 pub fn lifetime_to_str(e: &ast::Lifetime) -> String {
     to_str(|s| s.print_lifetime(e))
 }
 
+#[cfg(stage0)]
 pub fn tt_to_str(tt: &ast::TokenTree) -> String {
     to_str(|s| s.print_tt(tt))
 }
 
+#[cfg(stage0)]
 pub fn tts_to_str(tts: &[ast::TokenTree]) -> String {
     to_str(|s| s.print_tts(tts))
 }
 
+#[cfg(stage0)]
 pub fn stmt_to_str(stmt: &ast::Stmt) -> String {
     to_str(|s| s.print_stmt(stmt))
 }
 
+#[cfg(stage0)]
 pub fn item_to_str(i: &ast::Item) -> String {
     to_str(|s| s.print_item(i))
 }
 
+#[cfg(stage0)]
 pub fn generics_to_str(generics: &ast::Generics) -> String {
     to_str(|s| s.print_generics(generics))
 }
 
+#[cfg(stage0)]
 pub fn ty_method_to_str(p: &ast::TypeMethod) -> String {
     to_str(|s| s.print_ty_method(p))
 }
 
+#[cfg(stage0)]
 pub fn method_to_str(p: &ast::Method) -> String {
     to_str(|s| s.print_method(p))
 }
 
+#[cfg(stage0)]
 pub fn fn_block_to_str(p: &ast::FnDecl) -> String {
     to_str(|s| s.print_fn_block_args(p))
 }
 
+#[cfg(stage0)]
 pub fn path_to_str(p: &ast::Path) -> String {
     to_str(|s| s.print_path(p, false))
 }
 
-pub fn ident_to_str(id: &ast::Ident) -> String {
-    to_str(|s| s.print_ident(*id))
-}
-
+#[cfg(stage0)]
 pub fn fun_to_str(decl: &ast::FnDecl, fn_style: ast::FnStyle, name: ast::Ident,
                   opt_explicit_self: Option<ast::ExplicitSelf_>,
                   generics: &ast::Generics) -> String {
@@ -211,6 +341,7 @@ pub fn fun_to_str(decl: &ast::FnDecl, fn_style: ast::FnStyle, name: ast::Ident,
     })
 }
 
+#[cfg(stage0)]
 pub fn block_to_str(blk: &ast::Block) -> String {
     to_str(|s| {
         // containing cbox, will be closed by print-block at }
@@ -221,30 +352,39 @@ pub fn block_to_str(blk: &ast::Block) -> String {
     })
 }
 
+#[cfg(stage0)]
 pub fn meta_item_to_str(mi: &ast::MetaItem) -> String {
     to_str(|s| s.print_meta_item(mi))
 }
 
+#[cfg(stage0)]
 pub fn attribute_to_str(attr: &ast::Attribute) -> String {
     to_str(|s| s.print_attribute(attr))
 }
 
+#[cfg(stage0)]
 pub fn lit_to_str(l: &ast::Lit) -> String {
     to_str(|s| s.print_literal(l))
 }
 
+#[cfg(stage0)]
 pub fn explicit_self_to_str(explicit_self: ast::ExplicitSelf_) -> String {
     to_str(|s| s.print_explicit_self(explicit_self, ast::MutImmutable).map(|_| {}))
 }
 
+#[cfg(stage0)]
 pub fn variant_to_str(var: &ast::Variant) -> String {
     to_str(|s| s.print_variant(var))
 }
 
+#[cfg(stage0)]
 pub fn arg_to_str(arg: &ast::Arg) -> String {
     to_str(|s| s.print_arg(arg))
 }
 
+
+
+
 pub fn visibility_qualified(vis: ast::Visibility, s: &str) -> String {
     match vis {
         ast::Public => format!("pub {}", s),
@@ -674,7 +814,7 @@ impl<'a> State<'a> {
             }
             ast::ItemForeignMod(ref nmod) => {
                 try!(self.head("extern"));
-                try!(self.word_nbsp(nmod.abi.to_str().as_slice()));
+                try!(self.word_nbsp(nmod.abi.to_string().as_slice()));
                 try!(self.bopen());
                 try!(self.print_foreign_mod(nmod, item.attrs.as_slice()));
                 try!(self.bclose(item.span));
@@ -898,7 +1038,7 @@ impl<'a> State<'a> {
         match *tt {
             ast::TTDelim(ref tts) => self.print_tts(tts.as_slice()),
             ast::TTTok(_, ref tk) => {
-                try!(word(&mut self.s, parse::token::to_str(tk).as_slice()));
+                try!(word(&mut self.s, parse::token::to_string(tk).as_slice()));
                 match *tk {
                     parse::token::DOC_COMMENT(..) => {
                         hardbreak(&mut self.s)
@@ -915,7 +1055,7 @@ impl<'a> State<'a> {
                 match *sep {
                     Some(ref tk) => {
                         try!(word(&mut self.s,
-                                  parse::token::to_str(tk).as_slice()));
+                                  parse::token::to_string(tk).as_slice()));
                     }
                     None => ()
                 }
@@ -1313,11 +1453,11 @@ impl<'a> State<'a> {
             ast::ExprBinary(op, ref lhs, ref rhs) => {
                 try!(self.print_expr(&**lhs));
                 try!(space(&mut self.s));
-                try!(self.word_space(ast_util::binop_to_str(op)));
+                try!(self.word_space(ast_util::binop_to_string(op)));
                 try!(self.print_expr(&**rhs));
             }
             ast::ExprUnary(op, ref expr) => {
-                try!(word(&mut self.s, ast_util::unop_to_str(op)));
+                try!(word(&mut self.s, ast_util::unop_to_string(op)));
                 try!(self.print_expr_maybe_paren(&**expr));
             }
             ast::ExprAddrOf(m, ref expr) => {
@@ -1493,7 +1633,7 @@ impl<'a> State<'a> {
             ast::ExprAssignOp(op, ref lhs, ref rhs) => {
                 try!(self.print_expr(&**lhs));
                 try!(space(&mut self.s));
-                try!(word(&mut self.s, ast_util::binop_to_str(op)));
+                try!(word(&mut self.s, ast_util::binop_to_string(op)));
                 try!(self.word_space("="));
                 try!(self.print_expr(&**rhs));
             }
@@ -2337,11 +2477,11 @@ impl<'a> State<'a> {
             }
             ast::LitInt(i, t) => {
                 word(&mut self.s,
-                     ast_util::int_ty_to_str(t, Some(i)).as_slice())
+                     ast_util::int_ty_to_string(t, Some(i)).as_slice())
             }
             ast::LitUint(u, t) => {
                 word(&mut self.s,
-                     ast_util::uint_ty_to_str(t, Some(u)).as_slice())
+                     ast_util::uint_ty_to_string(t, Some(u)).as_slice())
             }
             ast::LitIntUnsuffixed(i) => {
                 word(&mut self.s, format!("{}", i).as_slice())
@@ -2351,7 +2491,7 @@ impl<'a> State<'a> {
                      format!(
                          "{}{}",
                          f.get(),
-                         ast_util::float_ty_to_str(t).as_slice()).as_slice())
+                         ast_util::float_ty_to_string(t).as_slice()).as_slice())
             }
             ast::LitFloatUnsuffixed(ref f) => word(&mut self.s, f.get()),
             ast::LitNil => word(&mut self.s, "()"),
@@ -2489,7 +2629,7 @@ impl<'a> State<'a> {
             Some(abi::Rust) => Ok(()),
             Some(abi) => {
                 try!(self.word_nbsp("extern"));
-                self.word_nbsp(abi.to_str().as_slice())
+                self.word_nbsp(abi.to_string().as_slice())
             }
             None => Ok(())
         }
@@ -2500,7 +2640,7 @@ impl<'a> State<'a> {
         match opt_abi {
             Some(abi) => {
                 try!(self.word_nbsp("extern"));
-                self.word_nbsp(abi.to_str().as_slice())
+                self.word_nbsp(abi.to_string().as_slice())
             }
             None => Ok(())
         }
@@ -2516,7 +2656,7 @@ impl<'a> State<'a> {
 
         if abi != abi::Rust {
             try!(self.word_nbsp("extern"));
-            try!(self.word_nbsp(abi.to_str().as_slice()));
+            try!(self.word_nbsp(abi.to_string().as_slice()));
         }
 
         word(&mut self.s, "fn")
@@ -2547,7 +2687,7 @@ mod test {
     use parse::token;
 
     #[test]
-    fn test_fun_to_str() {
+    fn test_fun_to_string() {
         let abba_ident = token::str_to_ident("abba");
 
         let decl = ast::FnDecl {
@@ -2559,13 +2699,13 @@ mod test {
             variadic: false
         };
         let generics = ast_util::empty_generics();
-        assert_eq!(&fun_to_str(&decl, ast::NormalFn, abba_ident,
+        assert_eq!(&fun_to_string(&decl, ast::NormalFn, abba_ident,
                                None, &generics),
                    &"fn abba()".to_string());
     }
 
     #[test]
-    fn test_variant_to_str() {
+    fn test_variant_to_string() {
         let ident = token::str_to_ident("principal_skinner");
 
         let var = codemap::respan(codemap::DUMMY_SP, ast::Variant_ {
@@ -2578,7 +2718,7 @@ mod test {
             vis: ast::Public,
         });
 
-        let varstr = variant_to_str(&var);
+        let varstr = variant_to_string(&var);
         assert_eq!(&varstr,&"pub principal_skinner".to_string());
     }
 }