Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

6 files changed, 788 insertions, 0 deletions

diff --git a/testing/mozbase/rust/mozrunner/Cargo.toml b/testing/mozbase/rust/mozrunner/Cargo.toml
new file mode 100644
index 0000000000..00beaee040
--- /dev/null
+++ b/testing/mozbase/rust/mozrunner/Cargo.toml
@@ -0,0 +1,22 @@
+[package]
+name = "mozrunner"
+version = "0.12.1"
+authors = ["Mozilla"]
+description = "Reliable Firefox process management."
+repository = "https://hg.mozilla.org/mozilla-central/file/tip/testing/mozbase/rust/mozrunner"
+license = "MPL-2.0"
+edition = "2018"
+
+[dependencies]
+log = "0.4"
+mozprofile = { path = "../mozprofile", version = "0.7" }
+plist = "0.5"
+
+[target.'cfg(target_os = "windows")'.dependencies]
+winreg = "0.5"
+
+[target.'cfg(target_os = "macos")'.dependencies]
+dirs = "2"
+
+[[bin]]
+name = "firefox-default-path"
diff --git a/testing/mozbase/rust/mozrunner/src/bin/firefox-default-path.rs b/testing/mozbase/rust/mozrunner/src/bin/firefox-default-path.rs
new file mode 100644
index 0000000000..94958aac90
--- /dev/null
+++ b/testing/mozbase/rust/mozrunner/src/bin/firefox-default-path.rs
@@ -0,0 +1,21 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+extern crate mozrunner;
+
+use mozrunner::runner::platform;
+use std::io::Write;
+
+fn main() {
+    let (path, code) = platform::firefox_default_path()
+        .map(|x| (x.to_string_lossy().into_owned(), 0))
+        .unwrap_or(("Firefox binary not found".to_owned(), 1));
+
+    let mut writer: Box<dyn Write> = match code {
+        0 => Box::new(std::io::stdout()),
+        _ => Box::new(std::io::stderr()),
+    };
+    writeln!(&mut writer, "{}", &*path).unwrap();
+    std::process::exit(code);
+}
diff --git a/testing/mozbase/rust/mozrunner/src/firefox_args.rs b/testing/mozbase/rust/mozrunner/src/firefox_args.rs
new file mode 100644
index 0000000000..610af2c044
--- /dev/null
+++ b/testing/mozbase/rust/mozrunner/src/firefox_args.rs
@@ -0,0 +1,191 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! Argument string parsing and matching functions for Firefox.
+//!
+//! Which arguments Firefox accepts and in what style depends on the platform.
+//! On Windows only, arguments can be prefixed with `/` (slash), such as
+//! `/foreground`.  Elsewhere, including Windows, arguments may be prefixed
+//! with both single (`-foreground`) and double (`--foreground`) dashes.
+//!
+//! An argument's name is determined by a space or an assignment operator (`=`)
+//! so that for the string `-foo=bar`, `foo` is considered the argument's
+//! basename.
+
+use std::ffi::{OsStr, OsString};
+
+use crate::runner::platform;
+
+fn parse_arg_name<T>(arg: T) -> Option<String>
+where
+    T: AsRef<OsStr>,
+{
+    let arg_os_str: &OsStr = arg.as_ref();
+    let arg_str = arg_os_str.to_string_lossy();
+
+    let mut start = 0;
+    let mut end = 0;
+
+    for (i, c) in arg_str.chars().enumerate() {
+        if i == 0 {
+            if !platform::arg_prefix_char(c) {
+                break;
+            }
+        } else if i == 1 {
+            if name_end_char(c) {
+                break;
+            } else if c != '-' {
+                start = i;
+                end = start + 1;
+            } else {
+                start = i + 1;
+                end = start;
+            }
+        } else {
+            end += 1;
+            if name_end_char(c) {
+                end -= 1;
+                break;
+            }
+        }
+    }
+
+    if start > 0 && end > start {
+        Some(arg_str[start..end].into())
+    } else {
+        None
+    }
+}
+
+fn name_end_char(c: char) -> bool {
+    c == ' ' || c == '='
+}
+
+/// Represents a Firefox command-line argument.
+#[derive(Debug, PartialEq)]
+pub enum Arg {
+    /// `-foreground` ensures application window gets focus, which is not the
+    /// default on macOS.
+    Foreground,
+
+    /// `-no-remote` prevents remote commands to this instance of Firefox, and
+    /// ensure we always start a new instance.
+    NoRemote,
+
+    /// `-P NAME` starts Firefox with a profile with a given name.
+    NamedProfile,
+
+    /// `-profile PATH` starts Firefox with the profile at the specified path.
+    Profile,
+
+    /// `-ProfileManager` starts Firefox with the profile chooser dialogue.
+    ProfileManager,
+
+    /// All other arguments.
+    Other(String),
+
+    /// Not an argument.
+    None,
+}
+
+impl<'a> From<&'a OsString> for Arg {
+    fn from(arg_str: &OsString) -> Arg {
+        if let Some(basename) = parse_arg_name(arg_str) {
+            match &*basename {
+                "profile" => Arg::Profile,
+                "P" => Arg::NamedProfile,
+                "ProfileManager" => Arg::ProfileManager,
+                "foreground" => Arg::Foreground,
+                "no-remote" => Arg::NoRemote,
+                _ => Arg::Other(basename),
+            }
+        } else {
+            Arg::None
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{parse_arg_name, Arg};
+    use std::ffi::OsString;
+
+    fn parse(arg: &str, name: Option<&str>) {
+        let result = parse_arg_name(arg);
+        assert_eq!(result, name.map(|x| x.to_string()));
+    }
+
+    #[test]
+    fn test_parse_arg_name() {
+        parse("-p", Some("p"));
+        parse("--p", Some("p"));
+        parse("--profile foo", Some("profile"));
+        parse("--profile", Some("profile"));
+        parse("--", None);
+        parse("", None);
+        parse("-=", None);
+        parse("--=", None);
+        parse("-- foo", None);
+        parse("foo", None);
+        parse("/ foo", None);
+        parse("/- foo", None);
+        parse("/=foo", None);
+        parse("foo", None);
+        parse("-profile", Some("profile"));
+        parse("-profile=foo", Some("profile"));
+        parse("-profile = foo", Some("profile"));
+        parse("-profile abc", Some("profile"));
+        parse("-profile /foo", Some("profile"));
+    }
+
+    #[cfg(target_os = "windows")]
+    #[test]
+    fn test_parse_arg_name_windows() {
+        parse("/profile", Some("profile"));
+    }
+
+    #[cfg(not(target_os = "windows"))]
+    #[test]
+    fn test_parse_arg_name_non_windows() {
+        parse("/profile", None);
+    }
+
+    #[test]
+    fn test_arg_from_osstring() {
+        assert_eq!(Arg::from(&OsString::from("-- profile")), Arg::None);
+        assert_eq!(Arg::from(&OsString::from("profile")), Arg::None);
+        assert_eq!(Arg::from(&OsString::from("profile -P")), Arg::None);
+        assert_eq!(
+            Arg::from(&OsString::from("-profiled")),
+            Arg::Other("profiled".into())
+        );
+        assert_eq!(
+            Arg::from(&OsString::from("-PROFILEMANAGER")),
+            Arg::Other("PROFILEMANAGER".into())
+        );
+
+        assert_eq!(Arg::from(&OsString::from("--profile")), Arg::Profile);
+        assert_eq!(Arg::from(&OsString::from("-profile foo")), Arg::Profile);
+
+        assert_eq!(
+            Arg::from(&OsString::from("--ProfileManager")),
+            Arg::ProfileManager
+        );
+        assert_eq!(
+            Arg::from(&OsString::from("-ProfileManager")),
+            Arg::ProfileManager
+        );
+
+        // TODO: -Ptest is valid
+        //assert_eq!(Arg::from(&OsString::from("-Ptest")), Arg::NamedProfile);
+        assert_eq!(Arg::from(&OsString::from("-P")), Arg::NamedProfile);
+        assert_eq!(Arg::from(&OsString::from("-P test")), Arg::NamedProfile);
+
+        assert_eq!(Arg::from(&OsString::from("--foreground")), Arg::Foreground);
+        assert_eq!(Arg::from(&OsString::from("-foreground")), Arg::Foreground);
+
+        assert_eq!(Arg::from(&OsString::from("--no-remote")), Arg::NoRemote);
+        assert_eq!(Arg::from(&OsString::from("-no-remote")), Arg::NoRemote);
+    }
+}
diff --git a/testing/mozbase/rust/mozrunner/src/lib.rs b/testing/mozbase/rust/mozrunner/src/lib.rs
new file mode 100644
index 0000000000..5634de11bf
--- /dev/null
+++ b/testing/mozbase/rust/mozrunner/src/lib.rs
@@ -0,0 +1,20 @@
+#![forbid(unsafe_code)]
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#[macro_use]
+extern crate log;
+#[cfg(target_os = "macos")]
+extern crate dirs;
+extern crate mozprofile;
+#[cfg(target_os = "macos")]
+extern crate plist;
+#[cfg(target_os = "windows")]
+extern crate winreg;
+
+pub mod firefox_args;
+pub mod path;
+pub mod runner;
+
+pub use crate::runner::platform::firefox_default_path;
diff --git a/testing/mozbase/rust/mozrunner/src/path.rs b/testing/mozbase/rust/mozrunner/src/path.rs
new file mode 100644
index 0000000000..215e72696f
--- /dev/null
+++ b/testing/mozbase/rust/mozrunner/src/path.rs
@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! Provides utilities for searching the system path.
+
+use std::env;
+use std::path::PathBuf;
+
+#[cfg(unix)]
+fn is_executable(path: &PathBuf) -> bool {
+    use std::fs;
+    use std::os::unix::fs::PermissionsExt;
+
+    // Permissions are a set of four 4-bit bitflags, represented by a single octal
+    // digit.  The lowest bit of each of the last three values represents the
+    // executable permission for all, group and user, repsectively.  We assume the
+    // file is executable if any of these are set.
+    match fs::metadata(path).ok() {
+        Some(meta) => meta.permissions().mode() & 0o111 != 0,
+        None => false,
+    }
+}
+
+#[cfg(not(unix))]
+fn is_executable(_: &PathBuf) -> bool {
+    true
+}
+
+/// Determines if the path is an executable binary.  That is, if it exists, is
+/// a file, and is executable where applicable.
+pub fn is_binary(path: &PathBuf) -> bool {
+    path.exists() && path.is_file() && is_executable(&path)
+}
+
+/// Searches the system path (`PATH`) for an executable binary and returns the
+/// first match, or `None` if not found.
+pub fn find_binary(binary_name: &str) -> Option<PathBuf> {
+    env::var_os("PATH").and_then(|path_env| {
+        for mut path in env::split_paths(&path_env) {
+            path.push(binary_name);
+            if is_binary(&path) {
+                return Some(path);
+            }
+        }
+        None
+    })
+}
diff --git a/testing/mozbase/rust/mozrunner/src/runner.rs b/testing/mozbase/rust/mozrunner/src/runner.rs
new file mode 100644
index 0000000000..485d94090c
--- /dev/null
+++ b/testing/mozbase/rust/mozrunner/src/runner.rs
@@ -0,0 +1,486 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use mozprofile::prefreader::PrefReaderError;
+use mozprofile::profile::Profile;
+use std::collections::HashMap;
+use std::convert::From;
+use std::error::Error;
+use std::ffi::{OsStr, OsString};
+use std::fmt;
+use std::io;
+use std::io::ErrorKind;
+use std::path::{Path, PathBuf};
+use std::process;
+use std::process::{Child, Command, Stdio};
+use std::thread;
+use std::time;
+
+use crate::firefox_args::Arg;
+
+pub trait Runner {
+    type Process;
+
+    fn arg<S>(&mut self, arg: S) -> &mut Self
+    where
+        S: AsRef<OsStr>;
+
+    fn args<I, S>(&mut self, args: I) -> &mut Self
+    where
+        I: IntoIterator<Item = S>,
+        S: AsRef<OsStr>;
+
+    fn env<K, V>(&mut self, key: K, value: V) -> &mut Self
+    where
+        K: AsRef<OsStr>,
+        V: AsRef<OsStr>;
+
+    fn envs<I, K, V>(&mut self, envs: I) -> &mut Self
+    where
+        I: IntoIterator<Item = (K, V)>,
+        K: AsRef<OsStr>,
+        V: AsRef<OsStr>;
+
+    fn stdout<T>(&mut self, stdout: T) -> &mut Self
+    where
+        T: Into<Stdio>;
+
+    fn stderr<T>(&mut self, stderr: T) -> &mut Self
+    where
+        T: Into<Stdio>;
+
+    fn start(self) -> Result<Self::Process, RunnerError>;
+}
+
+pub trait RunnerProcess {
+    /// Attempts to collect the exit status of the process if it has already exited.
+    ///
+    /// This function will not block the calling thread and will only advisorily check to see if
+    /// the child process has exited or not.  If the process has exited then on Unix the process ID
+    /// is reaped.  This function is guaranteed to repeatedly return a successful exit status so
+    /// long as the child has already exited.
+    ///
+    /// If the process has exited, then `Ok(Some(status))` is returned.  If the exit status is not
+    /// available at this time then `Ok(None)` is returned.  If an error occurs, then that error is
+    /// returned.
+    fn try_wait(&mut self) -> io::Result<Option<process::ExitStatus>>;
+
+    /// Waits for the process to exit completely, killing it if it does not stop within `timeout`,
+    /// and returns the status that it exited with.
+    ///
+    /// Firefox' integrated background monitor observes long running threads during shutdown and
+    /// kills these after 63 seconds.  If the process fails to exit within the duration of
+    /// `timeout`, it is forcefully killed.
+    ///
+    /// This function will continue to have the same return value after it has been called at least
+    /// once.
+    fn wait(&mut self, timeout: time::Duration) -> io::Result<process::ExitStatus>;
+
+    /// Determine if the process is still running.
+    fn running(&mut self) -> bool;
+
+    /// Forces the process to exit and returns the exit status.  This is
+    /// equivalent to sending a SIGKILL on Unix platforms.
+    fn kill(&mut self) -> io::Result<process::ExitStatus>;
+}
+
+#[derive(Debug)]
+pub enum RunnerError {
+    Io(io::Error),
+    PrefReader(PrefReaderError),
+}
+
+impl fmt::Display for RunnerError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            RunnerError::Io(ref err) => match err.kind() {
+                ErrorKind::NotFound => "no such file or directory".fmt(f),
+                _ => err.fmt(f),
+            },
+            RunnerError::PrefReader(ref err) => err.fmt(f),
+        }
+    }
+}
+
+impl Error for RunnerError {
+    fn cause(&self) -> Option<&dyn Error> {
+        Some(match *self {
+            RunnerError::Io(ref err) => err as &dyn Error,
+            RunnerError::PrefReader(ref err) => err as &dyn Error,
+        })
+    }
+}
+
+impl From<io::Error> for RunnerError {
+    fn from(value: io::Error) -> RunnerError {
+        RunnerError::Io(value)
+    }
+}
+
+impl From<PrefReaderError> for RunnerError {
+    fn from(value: PrefReaderError) -> RunnerError {
+        RunnerError::PrefReader(value)
+    }
+}
+
+#[derive(Debug)]
+pub struct FirefoxProcess {
+    process: Child,
+    profile: Profile,
+}
+
+impl RunnerProcess for FirefoxProcess {
+    fn try_wait(&mut self) -> io::Result<Option<process::ExitStatus>> {
+        self.process.try_wait()
+    }
+
+    fn wait(&mut self, timeout: time::Duration) -> io::Result<process::ExitStatus> {
+        let start = time::Instant::now();
+        loop {
+            match self.try_wait() {
+                // child has already exited, reap its exit code
+                Ok(Some(status)) => return Ok(status),
+
+                // child still running and timeout elapsed, kill it
+                Ok(None) if start.elapsed() >= timeout => return self.kill(),
+
+                // child still running, let's give it more time
+                Ok(None) => thread::sleep(time::Duration::from_millis(100)),
+
+                Err(e) => return Err(e),
+            }
+        }
+    }
+
+    fn running(&mut self) -> bool {
+        self.try_wait().unwrap().is_none()
+    }
+
+    fn kill(&mut self) -> io::Result<process::ExitStatus> {
+        match self.try_wait() {
+            // child has already exited, reap its exit code
+            Ok(Some(status)) => Ok(status),
+
+            // child still running, kill it
+            Ok(None) => {
+                debug!("Killing process {}", self.process.id());
+                self.process.kill()?;
+                self.process.wait()
+            }
+
+            Err(e) => Err(e),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct FirefoxRunner {
+    path: PathBuf,
+    profile: Profile,
+    args: Vec<OsString>,
+    envs: HashMap<OsString, OsString>,
+    stdout: Option<Stdio>,
+    stderr: Option<Stdio>,
+}
+
+impl FirefoxRunner {
+    /// Initialise Firefox process runner.
+    ///
+    /// On macOS, `path` can optionally point to an application bundle,
+    /// i.e. _/Applications/Firefox.app_, as well as to an executable program
+    /// such as _/Applications/Firefox.app/Content/MacOS/firefox-bin_.
+    pub fn new(path: &Path, profile: Profile) -> FirefoxRunner {
+        let mut envs: HashMap<OsString, OsString> = HashMap::new();
+        envs.insert("MOZ_NO_REMOTE".into(), "1".into());
+
+        FirefoxRunner {
+            path: path.to_path_buf(),
+            envs,
+            profile,
+            args: vec![],
+            stdout: None,
+            stderr: None,
+        }
+    }
+}
+
+impl Runner for FirefoxRunner {
+    type Process = FirefoxProcess;
+
+    fn arg<S>(&mut self, arg: S) -> &mut FirefoxRunner
+    where
+        S: AsRef<OsStr>,
+    {
+        self.args.push((&arg).into());
+        self
+    }
+
+    fn args<I, S>(&mut self, args: I) -> &mut FirefoxRunner
+    where
+        I: IntoIterator<Item = S>,
+        S: AsRef<OsStr>,
+    {
+        for arg in args {
+            self.args.push((&arg).into());
+        }
+        self
+    }
+
+    fn env<K, V>(&mut self, key: K, value: V) -> &mut FirefoxRunner
+    where
+        K: AsRef<OsStr>,
+        V: AsRef<OsStr>,
+    {
+        self.envs.insert((&key).into(), (&value).into());
+        self
+    }
+
+    fn envs<I, K, V>(&mut self, envs: I) -> &mut FirefoxRunner
+    where
+        I: IntoIterator<Item = (K, V)>,
+        K: AsRef<OsStr>,
+        V: AsRef<OsStr>,
+    {
+        for (key, value) in envs {
+            self.envs.insert((&key).into(), (&value).into());
+        }
+        self
+    }
+
+    fn stdout<T>(&mut self, stdout: T) -> &mut Self
+    where
+        T: Into<Stdio>,
+    {
+        self.stdout = Some(stdout.into());
+        self
+    }
+
+    fn stderr<T>(&mut self, stderr: T) -> &mut Self
+    where
+        T: Into<Stdio>,
+    {
+        self.stderr = Some(stderr.into());
+        self
+    }
+
+    fn start(mut self) -> Result<FirefoxProcess, RunnerError> {
+        self.profile.user_prefs()?.write()?;
+
+        let stdout = self.stdout.unwrap_or_else(Stdio::inherit);
+        let stderr = self.stderr.unwrap_or_else(Stdio::inherit);
+
+        let binary_path = platform::resolve_binary_path(&mut self.path);
+        let mut cmd = Command::new(binary_path);
+        cmd.args(&self.args[..])
+            .envs(&self.envs)
+            .stdout(stdout)
+            .stderr(stderr);
+
+        let mut seen_foreground = false;
+        let mut seen_no_remote = false;
+        let mut seen_profile = false;
+        for arg in self.args.iter() {
+            match arg.into() {
+                Arg::Foreground => seen_foreground = true,
+                Arg::NoRemote => seen_no_remote = true,
+                Arg::Profile | Arg::NamedProfile | Arg::ProfileManager => seen_profile = true,
+                Arg::Other(_) | Arg::None => {}
+            }
+        }
+        if !seen_foreground {
+            cmd.arg("-foreground");
+        }
+        if !seen_no_remote {
+            cmd.arg("-no-remote");
+        }
+        if !seen_profile {
+            cmd.arg("-profile").arg(&self.profile.path);
+        }
+
+        info!("Running command: {:?}", cmd);
+        let process = cmd.spawn()?;
+        Ok(FirefoxProcess {
+            process,
+            profile: self.profile,
+        })
+    }
+}
+
+#[cfg(all(not(target_os = "macos"), unix))]
+pub mod platform {
+    use crate::path::find_binary;
+    use std::path::PathBuf;
+
+    pub fn resolve_binary_path(path: &mut PathBuf) -> &PathBuf {
+        path
+    }
+
+    /// Searches the system path for `firefox`.
+    pub fn firefox_default_path() -> Option<PathBuf> {
+        find_binary("firefox")
+    }
+
+    pub fn arg_prefix_char(c: char) -> bool {
+        c == '-'
+    }
+}
+
+#[cfg(target_os = "macos")]
+pub mod platform {
+    use crate::path::{find_binary, is_binary};
+    use dirs;
+    use plist::Value;
+    use std::path::PathBuf;
+
+    /// Searches for the binary file inside the path passed as parameter.
+    /// If the binary is not found, the path remains unaltered.
+    /// Else, it gets updated by the new binary path.
+    pub fn resolve_binary_path(path: &mut PathBuf) -> &PathBuf {
+        if path.as_path().is_dir() {
+            let mut info_plist = path.clone();
+            info_plist.push("Contents");
+            info_plist.push("Info.plist");
+            if let Ok(plist) = Value::from_file(&info_plist) {
+                if let Some(dict) = plist.as_dictionary() {
+                    if let Some(binary_file) = dict.get("CFBundleExecutable") {
+                        if let Value::String(s) = binary_file {
+                            path.push("Contents");
+                            path.push("MacOS");
+                            path.push(s);
+                        }
+                    }
+                }
+            }
+        }
+        path
+    }
+
+    /// Searches the system path for `firefox-bin`, then looks for
+    /// `Applications/Firefox.app/Contents/MacOS/firefox-bin` as well
+    /// as `Applications/Firefox Nightly.app/Contents/MacOS/firefox-bin`
+    /// under both `/` (system root) and the user home directory.
+    pub fn firefox_default_path() -> Option<PathBuf> {
+        if let Some(path) = find_binary("firefox-bin") {
+            return Some(path);
+        }
+
+        let home = dirs::home_dir();
+        for &(prefix_home, trial_path) in [
+            (
+                false,
+                "/Applications/Firefox.app/Contents/MacOS/firefox-bin",
+            ),
+            (true, "Applications/Firefox.app/Contents/MacOS/firefox-bin"),
+            (
+                false,
+                "/Applications/Firefox Nightly.app/Contents/MacOS/firefox-bin",
+            ),
+            (
+                true,
+                "Applications/Firefox Nightly.app/Contents/MacOS/firefox-bin",
+            ),
+        ]
+        .iter()
+        {
+            let path = match (home.as_ref(), prefix_home) {
+                (Some(ref home_dir), true) => home_dir.join(trial_path),
+                (None, true) => continue,
+                (_, false) => PathBuf::from(trial_path),
+            };
+            if is_binary(&path) {
+                return Some(path);
+            }
+        }
+
+        None
+    }
+
+    pub fn arg_prefix_char(c: char) -> bool {
+        c == '-'
+    }
+}
+
+#[cfg(target_os = "windows")]
+pub mod platform {
+    use crate::path::{find_binary, is_binary};
+    use std::io::Error;
+    use std::path::PathBuf;
+    use winreg::enums::*;
+    use winreg::RegKey;
+
+    pub fn resolve_binary_path(path: &mut PathBuf) -> &PathBuf {
+        path
+    }
+
+    /// Searches the Windows registry, then the system path for `firefox.exe`.
+    ///
+    /// It _does not_ currently check the `HKEY_CURRENT_USER` tree.
+    pub fn firefox_default_path() -> Option<PathBuf> {
+        if let Ok(Some(path)) = firefox_registry_path() {
+            if is_binary(&path) {
+                return Some(path);
+            }
+        };
+        find_binary("firefox.exe")
+    }
+
+    fn firefox_registry_path() -> Result<Option<PathBuf>, Error> {
+        let hklm = RegKey::predef(HKEY_LOCAL_MACHINE);
+        for subtree_key in ["SOFTWARE", "SOFTWARE\\WOW6432Node"].iter() {
+            let subtree = hklm.open_subkey_with_flags(subtree_key, KEY_READ)?;
+            let mozilla_org = match subtree.open_subkey_with_flags("mozilla.org\\Mozilla", KEY_READ)
+            {
+                Ok(val) => val,
+                Err(_) => continue,
+            };
+            let current_version: String = mozilla_org.get_value("CurrentVersion")?;
+            let mozilla = subtree.open_subkey_with_flags("Mozilla", KEY_READ)?;
+            for key_res in mozilla.enum_keys() {
+                let key = key_res?;
+                let section_data = mozilla.open_subkey_with_flags(&key, KEY_READ)?;
+                let version: Result<String, _> = section_data.get_value("GeckoVer");
+                if let Ok(ver) = version {
+                    if ver == current_version {
+                        let mut bin_key = key.to_owned();
+                        bin_key.push_str("\\bin");
+                        if let Ok(bin_subtree) = mozilla.open_subkey_with_flags(bin_key, KEY_READ) {
+                            let path_to_exe: Result<String, _> = bin_subtree.get_value("PathToExe");
+                            if let Ok(path_to_exe) = path_to_exe {
+                                let path = PathBuf::from(path_to_exe);
+                                if is_binary(&path) {
+                                    return Ok(Some(path));
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        Ok(None)
+    }
+
+    pub fn arg_prefix_char(c: char) -> bool {
+        c == '/' || c == '-'
+    }
+}
+
+#[cfg(not(any(unix, target_os = "windows")))]
+pub mod platform {
+    use std::path::PathBuf;
+
+    /// Returns an unaltered path for all operating systems other than macOS.
+    pub fn resolve_binary_path(path: &mut PathBuf) -> &PathBuf {
+        path
+    }
+
+    /// Returns `None` for all other operating systems than Linux, macOS, and
+    /// Windows.
+    pub fn firefox_default_path() -> Option<PathBuf> {
+        None
+    }
+
+    pub fn arg_prefix_char(c: char) -> bool {
+        c == '-'
+    }
+}