Remove a `bool` for color in favor of the `WriteColor` trait wrapping colored and uncolored printing

7 files changed, 49 insertions, 25 deletions

diff --git a/Cargo.lock b/Cargo.lock
index dd8ce11ac12..7b7c0fd60d8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3619,6 +3619,7 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "smallvec",
+ "termcolor",
  "thin-vec",
  "tracing",
 ]
diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 41fb1cafe25..87b3a25ed44 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -61,12 +61,15 @@ impl HumanReadableErrorType {
     }
     pub fn new_emitter(
         self,
-        dst: Box<dyn Write + Send>,
+        mut dst: Box<dyn WriteColor + Send>,
         fallback_bundle: LazyFallbackBundle,
     ) -> EmitterWriter {
         let (short, color_config) = self.unzip();
         let color = color_config.suggests_using_colors();
-        EmitterWriter::new(dst, fallback_bundle, color).short_message(short)
+        if !dst.supports_color() && color {
+            dst = Box::new(Ansi::new(dst));
+        }
+        EmitterWriter::new(dst, fallback_bundle).short_message(short)
     }
 }
 
@@ -669,11 +672,10 @@ impl EmitterWriter {
     }
 
     pub fn new(
-        dst: Box<dyn Write + Send>,
+        dst: Box<dyn WriteColor + Send>,
         fallback_bundle: LazyFallbackBundle,
-        colored: bool,
     ) -> EmitterWriter {
-        Self::create(Raw(dst, colored), fallback_bundle)
+        Self::create(Raw(dst), fallback_bundle)
     }
 
     fn maybe_anonymized(&self, line_num: usize) -> Cow<'static, str> {
@@ -2603,15 +2605,13 @@ fn emit_to_destination(
 pub enum Destination {
     Terminal(StandardStream),
     Buffered(BufferWriter),
-    // The bool denotes whether we should be emitting ansi color codes or not
-    Raw(Box<(dyn Write + Send)>, bool),
+    Raw(Box<(dyn WriteColor + Send)>),
 }
 
 pub enum WritableDst<'a> {
     Terminal(&'a mut StandardStream),
     Buffered(&'a mut BufferWriter, Buffer),
-    Raw(&'a mut (dyn Write + Send)),
-    ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
+    Raw(&'a mut (dyn WriteColor + Send)),
 }
 
 impl Destination {
@@ -2637,8 +2637,7 @@ impl Destination {
                 let buf = t.buffer();
                 WritableDst::Buffered(t, buf)
             }
-            Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
-            Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
+            Destination::Raw(ref mut t) => WritableDst::Raw(t),
         }
     }
 
@@ -2646,7 +2645,7 @@ impl Destination {
         match *self {
             Self::Terminal(ref stream) => stream.supports_color(),
             Self::Buffered(ref buffer) => buffer.buffer().supports_color(),
-            Self::Raw(_, supports_color) => supports_color,
+            Self::Raw(ref writer) => writer.supports_color(),
         }
     }
 }
@@ -2706,8 +2705,7 @@ impl<'a> WritableDst<'a> {
         match *self {
             WritableDst::Terminal(ref mut t) => t.set_color(color),
             WritableDst::Buffered(_, ref mut t) => t.set_color(color),
-            WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
-            WritableDst::Raw(_) => Ok(()),
+            WritableDst::Raw(ref mut t) => t.set_color(color),
         }
     }
 
@@ -2715,8 +2713,7 @@ impl<'a> WritableDst<'a> {
         match *self {
             WritableDst::Terminal(ref mut t) => t.reset(),
             WritableDst::Buffered(_, ref mut t) => t.reset(),
-            WritableDst::ColoredRaw(ref mut t) => t.reset(),
-            WritableDst::Raw(_) => Ok(()),
+            WritableDst::Raw(ref mut t) => t.reset(),
         }
     }
 }
@@ -2727,7 +2724,6 @@ impl<'a> Write for WritableDst<'a> {
             WritableDst::Terminal(ref mut t) => t.write(bytes),
             WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
             WritableDst::Raw(ref mut w) => w.write(bytes),
-            WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
         }
     }
 
@@ -2736,7 +2732,6 @@ impl<'a> Write for WritableDst<'a> {
             WritableDst::Terminal(ref mut t) => t.flush(),
             WritableDst::Buffered(_, ref mut buf) => buf.flush(),
             WritableDst::Raw(ref mut w) => w.flush(),
-            WritableDst::ColoredRaw(ref mut w) => w.flush(),
         }
     }
 }
diff --git a/compiler/rustc_errors/src/json.rs b/compiler/rustc_errors/src/json.rs
index e199244b1e4..b8f58e3057c 100644
--- a/compiler/rustc_errors/src/json.rs
+++ b/compiler/rustc_errors/src/json.rs
@@ -10,6 +10,7 @@
 // FIXME: spec the JSON output properly.
 
 use rustc_span::source_map::{FilePathMapping, SourceMap};
+use termcolor::{ColorSpec, WriteColor};
 
 use crate::emitter::{Emitter, HumanReadableErrorType};
 use crate::registry::Registry;
@@ -356,6 +357,19 @@ impl Diagnostic {
                 self.0.lock().unwrap().flush()
             }
         }
+        impl WriteColor for BufWriter {
+            fn supports_color(&self) -> bool {
+                false
+            }
+
+            fn set_color(&mut self, _spec: &ColorSpec) -> io::Result<()> {
+                Ok(())
+            }
+
+            fn reset(&mut self) -> io::Result<()> {
+                Ok(())
+            }
+        }
         let buf = BufWriter::default();
         let output = buf.clone();
         je.json_rendered
diff --git a/compiler/rustc_expand/Cargo.toml b/compiler/rustc_expand/Cargo.toml
index 2dae0e3f53c..02da5b5dc53 100644
--- a/compiler/rustc_expand/Cargo.toml
+++ b/compiler/rustc_expand/Cargo.toml
@@ -27,3 +27,4 @@ rustc_span = { path = "../rustc_span" }
 smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
 thin-vec = "0.2.12"
 tracing = "0.1"
+termcolor = "1.2"
diff --git a/compiler/rustc_expand/src/tests.rs b/compiler/rustc_expand/src/tests.rs
index 4d1d834ed2b..8e3219c138c 100644
--- a/compiler/rustc_expand/src/tests.rs
+++ b/compiler/rustc_expand/src/tests.rs
@@ -9,6 +9,7 @@ use rustc_span::{BytePos, Span};
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::emitter::EmitterWriter;
 use rustc_errors::{Handler, MultiSpan, PResult};
+use termcolor::WriteColor;
 
 use std::io;
 use std::io::prelude::*;
@@ -29,10 +30,9 @@ fn create_test_handler() -> (Handler, Lrc<SourceMap>, Arc<Mutex<Vec<u8>>>) {
         vec![crate::DEFAULT_LOCALE_RESOURCE, rustc_parse::DEFAULT_LOCALE_RESOURCE],
         false,
     );
-    let emitter =
-        EmitterWriter::new(Box::new(Shared { data: output.clone() }), fallback_bundle, false)
-            .sm(Some(source_map.clone()))
-            .diagnostic_width(Some(140));
+    let emitter = EmitterWriter::new(Box::new(Shared { data: output.clone() }), fallback_bundle)
+        .sm(Some(source_map.clone()))
+        .diagnostic_width(Some(140));
     let handler = Handler::with_emitter(Box::new(emitter));
     (handler, source_map, output)
 }
@@ -156,6 +156,20 @@ pub(crate) struct Shared<T: Write> {
     pub data: Arc<Mutex<T>>,
 }
 
+impl<T: Write> WriteColor for Shared<T> {
+    fn supports_color(&self) -> bool {
+        false
+    }
+
+    fn set_color(&mut self, _spec: &termcolor::ColorSpec) -> io::Result<()> {
+        Ok(())
+    }
+
+    fn reset(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
 impl<T: Write> Write for Shared<T> {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.data.lock().unwrap().write(buf)
diff --git a/src/librustdoc/doctest.rs b/src/librustdoc/doctest.rs
index 1afac214da3..3315ccad4d3 100644
--- a/src/librustdoc/doctest.rs
+++ b/src/librustdoc/doctest.rs
@@ -562,7 +562,7 @@ pub(crate) fn make_test(
                 .diagnostic_width(Some(80))
                 .supports_color();
 
-            let emitter = EmitterWriter::new(Box::new(io::sink()), fallback_bundle, false);
+            let emitter = EmitterWriter::new(Box::new(io::sink()), fallback_bundle);
 
             // FIXME(misdreavus): pass `-Z treat-err-as-bug` to the doctest parser
             let handler = Handler::with_emitter(Box::new(emitter)).disable_warnings();
@@ -738,7 +738,7 @@ fn check_if_attr_is_complete(source: &str, edition: Edition) -> bool {
                 false,
             );
 
-            let emitter = EmitterWriter::new(Box::new(io::sink()), fallback_bundle, false);
+            let emitter = EmitterWriter::new(Box::new(io::sink()), fallback_bundle);
 
             let handler = Handler::with_emitter(Box::new(emitter)).disable_warnings();
             let sess = ParseSess::with_span_handler(handler, sm);
diff --git a/src/tools/clippy/clippy_lints/src/doc.rs b/src/tools/clippy/clippy_lints/src/doc.rs
index 573838ce63e..2c4d93e33ba 100644
--- a/src/tools/clippy/clippy_lints/src/doc.rs
+++ b/src/tools/clippy/clippy_lints/src/doc.rs
@@ -719,7 +719,6 @@ fn check_code(cx: &LateContext<'_>, text: &str, edition: Edition, span: Span) {
                 let emitter = EmitterWriter::new(
                     Box::new(io::sink()),
                     fallback_bundle,
-                    false,
                 );
                 let handler = Handler::with_emitter(Box::new(emitter)).disable_warnings();
                 let sess = ParseSess::with_span_handler(handler, sm);