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

Cargo.lock

@@ -98,6 +98,7 @@ dependencies = [
  "git2",
  "globset",
  "lazy_static",
+ "nix",
  "path_abs",
  "predicates",
  "semver",
@@ -213,12 +214,12 @@ dependencies = [
 
 [[package]]
 name = "clircle"
-version = "0.2.0"
+version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e27a01e782190a8314e65cc94274d9bbcd52e05a9d15b437fe2b31259b854b0d"
+checksum = "e68bbd985a63de680ab4d1ad77b6306611a8f961b282c8b5ab513e6de934e396"
 dependencies = [
  "cfg-if",
- "nix",
+ "libc",
  "serde",
  "winapi",
 ]

Cargo.toml

@@ -48,7 +48,7 @@ serde = { version = "1.0", features = ["derive"] }
 serde_yaml = "0.8"
 semver = "0.11"
 path_abs = { version = "0.5", default-features = false }
-clircle = "0.2.0"
+clircle = "0.3"
 bugreport = "0.3"
 dirs-next = { version = "2.0.0", optional = true }
 

src/assets.rs

@@ -329,7 +329,7 @@ mod tests {
 
             let input = Input::ordinary_file(file_path.as_os_str());
             let dummy_stdin: &[u8] = &[];
-            let mut opened_input = input.open(dummy_stdin).unwrap();
+            let mut opened_input = input.open(dummy_stdin, None).unwrap();
 
             self.assets
                 .get_syntax(None, &mut opened_input, &self.syntax_mapping)
@@ -343,7 +343,7 @@ mod tests {
             let input = Input::from_reader(Box::new(BufReader::new(first_line.as_bytes())))
                 .with_name(Some(file_path.as_os_str()));
             let dummy_stdin: &[u8] = &[];
-            let mut opened_input = input.open(dummy_stdin).unwrap();
+            let mut opened_input = input.open(dummy_stdin, None).unwrap();
 
             self.assets
                 .get_syntax(None, &mut opened_input, &self.syntax_mapping)
@@ -367,7 +367,7 @@ mod tests {
 
         fn syntax_for_stdin_with_content(&self, file_name: &str, content: &[u8]) -> String {
             let input = Input::stdin().with_name(Some(OsStr::new(file_name)));
-            let mut opened_input = input.open(content).unwrap();
+            let mut opened_input = input.open(content, None).unwrap();
 
             self.assets
                 .get_syntax(None, &mut opened_input, &self.syntax_mapping)
@@ -523,7 +523,7 @@ mod tests {
 
         let input = Input::ordinary_file(file_path_symlink.as_os_str());
         let dummy_stdin: &[u8] = &[];
-        let mut opened_input = input.open(dummy_stdin).unwrap();
+        let mut opened_input = input.open(dummy_stdin, None).unwrap();
 
         assert_eq!(
             test.assets

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;

src/input.rs

@@ -2,8 +2,8 @@ use std::convert::TryFrom;
 use std::ffi::{OsStr, OsString};
 use std::fs::File;
 use std::io::{self, BufRead, BufReader, Read};
-use std::path::Path;
 
+use clircle::{Clircle, Identifier};
 use content_inspector::{self, ContentType};
 
 use crate::error::*;
@@ -157,25 +157,55 @@ impl<'a> Input<'a> {
         &mut self.description
     }
 
-    pub(crate) fn open<R: BufRead + 'a>(self, stdin: R) -> Result<OpenedInput<'a>> {
+    pub(crate) fn open<R: BufRead + 'a>(
+        self,
+        stdin: R,
+        stdout_identifier: Option<&Identifier>,
+    ) -> Result<OpenedInput<'a>> {
         let description = self.description().clone();
         match self.kind {
-            InputKind::StdIn => Ok(OpenedInput {
-                kind: OpenedInputKind::StdIn,
-                description,
-                metadata: self.metadata,
-                reader: InputReader::new(stdin),
-            }),
+            InputKind::StdIn => {
+                if let Some(stdout) = stdout_identifier {
+                    let input_identifier = Identifier::try_from(clircle::Stdio::Stdin)
+                        .map_err(|e| format!("Stdin: Error identifying file: {}", e))?;
+                    if stdout.surely_conflicts_with(&input_identifier) {
+                        return Err("IO circle detected. The input from stdin is also an output. Aborting to avoid infinite loop.".into());
+                    }
+                }
+
+                Ok(OpenedInput {
+                    kind: OpenedInputKind::StdIn,
+                    description,
+                    metadata: self.metadata,
+                    reader: InputReader::new(stdin),
+                })
+            }
+
             InputKind::OrdinaryFile(path) => Ok(OpenedInput {
                 kind: OpenedInputKind::OrdinaryFile(path.clone()),
                 description,
                 metadata: self.metadata,
                 reader: {
-                    let file = File::open(&path)
+                    let mut file = File::open(&path)
                         .map_err(|e| format!("'{}': {}", path.to_string_lossy(), e))?;
                     if file.metadata()?.is_dir() {
                         return Err(format!("'{}' is a directory.", path.to_string_lossy()).into());
                     }
+
+                    if let Some(stdout) = stdout_identifier {
+                        let input_identifier = Identifier::try_from(file).map_err(|e| {
+                            format!("{}: Error identifying file: {}", path.to_string_lossy(), e)
+                        })?;
+                        if stdout.surely_conflicts_with(&input_identifier) {
+                            return Err(format!(
+                                "IO circle detected. The input from '{}' is also an output. Aborting to avoid infinite loop.",
+                                path.to_string_lossy()
+                            )
+                            .into());
+                        }
+                        file = input_identifier.into_inner().expect("The file was lost in the clircle::Identifier, this should not have happended...");
+                    }
+
                     InputReader::new(BufReader::new(file))
                 },
             }),
@@ -189,18 +219,6 @@ impl<'a> Input<'a> {
     }
 }
 
-impl TryFrom<&'_ Input<'_>> for clircle::Identifier {
-    type Error = ();
-
-    fn try_from(input: &Input) -> std::result::Result<clircle::Identifier, ()> {
-        match input.kind {
-            InputKind::OrdinaryFile(ref path) => Self::try_from(Path::new(path)).map_err(|_| ()),
-            InputKind::StdIn => Self::try_from(clircle::Stdio::Stdin).map_err(|_| ()),
-            InputKind::CustomReader(_) => Err(()),
-        }
-    }
-}
-
 pub(crate) struct InputReader<'a> {
     inner: Box<dyn BufRead + 'a>,
     pub(crate) first_line: Vec<u8>,