Remove some dead code

src/cancellable.h

@@ -0,0 +1,53 @@
+#ifndef FISH_CANCELLABLE_H
+#define FISH_CANCELLABLE_H
+
+#include "maybe.h"
+
+/// A simple value type representing cancellation via a signal.
+struct cancellation_t {
+    int signal;
+
+    explicit cancellation_t(int sig) : signal(sig) {}
+};
+
+/// A cancellable_t<T> is a wrapper around T which may be cancelled, for example by a signal.
+template <typename T>
+class cancellable_t : private maybe_t<T> {
+    using super = maybe_t<T>;
+
+   public:
+    /// Construct from a T.
+    /* implicit */ cancellable_t(T &&v) : super(v) {}
+    /* implicit */ cancellable_t(const T &v) : super(v) {}
+
+    /// Construct from a cancellation.
+    /* implicit */ cancellable_t(cancellation_t c) : super(none()), signal_(c.signal) {}
+
+    cancellable_t(const cancellable_t &) = default;
+    cancellable_t(cancellable_t &&) = default;
+
+    /// Access the cancellation signal, if this was cancelled.
+    int signal() const {
+        assert(!has_value() && "Not cancelled");
+        return signal_;
+    }
+
+    /// \return whether this was cancelled.
+    bool is_cancelled() const { return !has_value(); }
+
+    // Expose maybe_t<T>::value and dereferencing.
+    using super::has_value;
+    using super::value;
+    using super::operator->;
+    using super::operator*;
+
+    /// Notice we don't compare signals when checking for equality.
+    bool operator==(const cancellable_t &rhs) const { super::operator==(rhs); }
+    bool operator!=(const cancellable_t &rhs) const { super::operator!=(rhs); }
+
+   private:
+    // The cancellation signal.
+    int signal_{0};
+};
+
+#endif

src/common.cpp

@@ -250,38 +250,6 @@ bool is_windows_subsystem_for_linux() {
 }
 #endif  // HAVE_BACKTRACE_SYMBOLS
 
-int fgetws2(wcstring *s, FILE *f) {
-    int i = 0;
-    wint_t c;
-
-    while (true) {
-        errno = 0;
-
-        c = std::fgetwc(f);
-        if (errno == EILSEQ || errno == EINTR) {
-            continue;
-        }
-
-        switch (c) {
-            // End of line.
-            case WEOF:
-            case L'\n':
-            case L'\0': {
-                return i;
-            }
-            // Ignore carriage returns.
-            case L'\r': {
-                break;
-            }
-            default: {
-                i++;
-                s->push_back(static_cast<wchar_t>(c));
-                break;
-            }
-        }
-    }
-}
-
 /// Converts the narrow character string \c in into its wide equivalent, and return it.
 ///
 /// The string may contain embedded nulls.

src/common.h

@@ -269,14 +269,6 @@ std::shared_ptr<T> move_to_sharedptr(T &&v) {
 /// Print a stack trace to stderr.
 void show_stackframe(const wchar_t msg_level, int frame_count = 100, int skip_levels = 0);
 
-/// Read a line from the stream f into the string. Returns the number of bytes read or -1 on
-/// failure.
-///
-/// If the carriage return character is encountered, it is ignored. fgetws() considers the line to
-/// end if reading the file results in either a newline (L'\n') character, the null (L'\\0')
-/// character or the end of file (WEOF) character.
-int fgetws2(wcstring *s, FILE *f);
-
 /// Returns a  wide character string equivalent of the specified multibyte character string.
 ///
 /// This function encodes illegal character sequences in a reversible way using the private use
@@ -768,12 +760,6 @@ std::unique_ptr<T> make_unique(Args &&... args) {
 /// \param in the position of the opening quote.
 wchar_t *quote_end(const wchar_t *pos);
 
-/// A call to this function will reset the error counter. Some functions print out non-critical
-/// error messages. These should check the error_count before, and skip printing the message if
-/// MAX_ERROR_COUNT messages have been printed. The error_reset() should be called after each
-/// interactive command executes, to allow new messages to be printed.
-void error_reset();
-
 /// This function should be called after calling `setlocale()` to perform fish specific locale
 /// initialization.
 void fish_setlocale();