Change circle detection to use new more conservative method and run in main loop instead of before the loop

src/controller.rs

@@ -1,4 +1,3 @@
-use std::convert::TryFrom;
 use std::io::{self, Write};
 
 use crate::assets::HighlightingAssets;
@@ -15,6 +14,8 @@ use crate::output::OutputType;
 use crate::paging::PagingMode;
 use crate::printer::{InteractivePrinter, Printer, SimplePrinter};
 
+use clircle::Clircle;
+
 pub struct Controller<'a> {
     config: &'a Config<'a>,
     assets: &'a HighlightingAssets,
@@ -67,12 +68,10 @@ impl<'b> Controller<'b> {
         }
 
         let attached_to_pager = output_type.is_pager();
-        let rw_cycle_detected = !attached_to_pager && {
-            let identifiers: Vec<_> = inputs
-                .iter()
-                .flat_map(clircle::Identifier::try_from)
-                .collect();
-            clircle::stdout_among_inputs(&identifiers)
+        let stdout_identifier = if cfg!(windows) || attached_to_pager {
+            None
+        } else {
+            clircle::Identifier::stdout()
         };
 
         let writer = output_type.handle()?;
@@ -87,13 +86,8 @@ impl<'b> Controller<'b> {
             }
         };
 
-        if rw_cycle_detected {
-            print_error(&"The output file is also an input!".into(), writer);
-            return Ok(false);
-        }
-
         for (index, input) in inputs.into_iter().enumerate() {
-            match input.open(io::stdin().lock()) {
+            match input.open(io::stdin().lock(), stdout_identifier.as_ref()) {
                 Err(error) => {
                     print_error(&error, writer);
                     no_errors = false;