strerror.rs(3), getopt.rs(3): renames

src/libgetopt.rs

@@ -0,0 +1,202 @@
+/*
+ * Copyright (c) 2023–2024 Emma Tebibyte <emma@tebibyte.media>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ */
+
+use std::ffi::{ c_int, c_char, CString, CStr };
+
+/* binding to getopt(3p) */
+extern "C" {
+	static mut optarg: *mut c_char;
+	static mut _opterr: c_int;
+	static mut optind: c_int;
+	static mut optopt: c_int;
+
+	fn getopt(
+		___argc: c_int,
+		___argv: *const *mut c_char,
+		__shortopts: *const c_char,
+	) -> c_int;
+}
+
+#[derive(Clone, Debug)]
+pub enum OptError {
+	MissingArg(String),
+	UnknownOpt(String),
+}
+
+#[derive(Clone, Debug)]
+pub struct Opt {
+	arg: Option<String>, /* option argument */
+	ind: *mut i32, /* option index */
+	opt: Result<String, OptError>, /* option option */
+}
+
+impl Opt {
+	pub fn arg(&self) -> Option<String> { self.arg.clone() }
+
+	/* sets optarg if default is desired */
+	pub fn arg_or(&self, default: impl std::fmt::Display) -> String {
+		default.to_string()
+	}
+
+	/* makes matching the output of this method more bearable */
+	pub fn opt(&self) -> Result<&str, OptError> {
+		self.opt.as_ref().map(|o| o.as_str()).map_err(OptError::clone)
+	}
+
+	/* From getopt(3p):
+	 *
+	 * The variable optind is the index of the next element of the argv[]
+	 * vector to be processed. It shall be initialized to 1 by the system, and
+	 * getopt() shall update it when it finishes with each element of argv[].
+	 * If the application sets optind to zero  before calling getopt(), the
+	 * behavior is unspecified. When an element of argv[] contains multiple
+	 * option characters, it is unspecified how getopt() determines which
+	 * options have already been processed. */
+	pub fn ind(&self) -> usize { unsafe { *self.ind as usize } }
+
+	/* this is patently terrible and is only happening because I’m stubborn */
+	pub fn set_ind(&self, ind: i32) { unsafe { *self.ind = ind; } }
+}
+
+/* function signature */
+pub trait GetOpt {
+	fn getopt(&self, optstring: &str) -> Option<Opt>;
+}
+
+impl GetOpt for Vec<String> {
+    fn getopt(&self, optstring: &str) -> Option<Opt> {
+        let c_strings: Vec<_> = self
+			.iter()
+			.cloned()
+			.map(|x| CString::new(x).unwrap().into_raw())
+			.collect();
+
+		/* god knows what this does */
+		let boxed = Box::into_raw(c_strings.into_boxed_slice());
+		let argv = boxed as *const *mut i8;
+
+		/* operations are separated out so that everything lives long enough */
+        let opts = CString::new(optstring).unwrap().into_raw();
+        let len = self.len() as c_int;
+
+        unsafe {
+            let ret = match getopt(len, argv, opts) { 
+				/* From getopt(3p):
+				 *
+				 * The getopt() function shall return the next option character
+				 * specified on the command line.
+				 *
+				 * A <colon> (':') shall be returned if getopt() detects a
+				 * missing argument and the first character of optstring was a
+				 * <colon> (':').
+				 *
+				 * A <question-mark> ('?') shall be returned if getopt()
+				 * encounters an option character not in optstring or detects a
+				 * missing argument and the first character of optstring was not
+				 * a <colon> (':').
+				 *
+				 * Otherwise, getopt() shall return -1 when all command line
+				 * options are parsed. */
+				58 => { /* ASCII ':' */
+					Some(Opt {
+						arg: None,
+						ind: std::ptr::addr_of_mut!(optind),
+						/* error containing option */
+						opt: Err(OptError::MissingArg(optopt.to_string())),
+					})
+				},
+				63 => { /* ASCII '?' */
+					Some(Opt {
+						arg: None,
+						ind: std::ptr::addr_of_mut!(optind),
+						/* error containing option */
+						opt: Err(OptError::UnknownOpt(optopt.to_string())),
+					})
+				},
+				/* From getopt(3p):
+				 *
+				 * If, when getopt() is called:
+				 *
+				 * argv[optind]  is a null pointer
+				 * *argv[optind]  is not the character -
+				 * argv[optind]  points to the string "-"
+				 *
+				 * getopt() shall return -1 without changing optind.  If:
+				 *
+				 * argv[optind]   points to the string "--"
+				 *
+				 * getopt() shall return -1 after incrementing optind. */
+                -1 => return None,
+                opt => {
+					let arg: Option<String>;
+
+					if optarg.is_null() { arg = None; }
+					else {
+						arg = Some(CStr::from_ptr(optarg)
+							.to_string_lossy()
+							.into_owned());
+					}
+
+					Some(Opt {
+						arg,
+						ind: std::ptr::addr_of_mut!(optind),
+						/* I didn’t need to cast this before; I rewrote the
+						 * pointer logic and now I do
+						 *
+						 * I don’t know why this is */
+						opt: Ok((opt as u8 as char).to_string()),
+					})
+				},
+            };
+
+			/* delloc argv (something online said I should do this) */
+			let _ = Box::from_raw(boxed);
+			return ret;
+        }
+    }
+}
+
+/* tests (good) */
+#[cfg(test)]
+mod tests {
+	use GetOpt;
+
+	#[test]
+	fn testing() {
+		let argv: Vec<String> = ["test", "-b", "-f", "arg", "-o", "arg"]
+			.iter()
+			.map(|s| s.to_string())
+			.collect();
+
+		while let Some(opt) = argv.getopt(":abf:o:") {
+			match opt.opt() {
+				Ok("a") => assert_eq!(opt.ind(), 1),
+				Ok("b") => assert_eq!(opt.ind(), 2),
+				Ok("f") | Ok("o") => {
+					assert_eq!(opt.arg(), Some("arg".into()));
+				},
+				_ => assert!(false),
+			};
+		}
+
+		if let Some(opt) = argv.getopt("abc:") {
+			opt.clone().set_ind(1);
+			assert_eq!(opt.ind(), 1);
+		}
+	}
+}