bumped MSRV to 1.48.0, minor improvements

- this is the rust version that debian stable (buster) currently has, so that's nice
- now we can use `const fn`s in more places, hooray
- smartstring is no longer outdated, hooray
- bitflags is no longer outdated, hooray
- mime_type in files.rs is now a bit smarter about not reading more than it has to, hooray
- removed some redundant clippy lints, hooray
- added a teensy smidgen more documentation, hooray

.gitlab-ci.yml

@@ -81,15 +81,8 @@ clippy:
 cleanup-stable:
   extends: .cargo-cleanup
 
-# commented out because cargo-sweep no longer works on our MSRV
-#cleanup-msrv:
-#  extends: cleanup-stable
-#  image: "rust:1.43.0"
-#  cache:
-#    key: msrv
-#    paths:
-#      - target
-#      - .cargo
+# there's no point running cargo sweep on MSRV, since it's always at the same version (and therefore cargo sweep will
+# never delete anything)
 
 cleanup-nightly:
   extends: cleanup-stable
@@ -107,8 +100,7 @@ build-base-stable:
 
 build-base-msrv:
   extends: build-base-stable
-#  needs: ["cleanup-msrv"]
-  image: "rust:1.43.0"
+  image: "rust:1.48.0"
   cache:
     key: msrv
     paths:
@@ -134,7 +126,7 @@ build-stable:
 build-msrv:
   extends: build-stable
   needs: ["build-base-msrv"]
-  image: "rust:1.43.0"
+  image: "rust:1.48.0"
   cache:
     key: msrv
     paths:
@@ -159,7 +151,7 @@ test-stable:
 
 test-msrv:
   extends: test-stable
-  image: "rust:1.43.0"
+  image: "rust:1.48.0"
   needs: ["build-msrv"]
   cache:
     key: msrv

CHANGELOG.md

@@ -18,6 +18,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
   - For a more thorough breakdown of how these flags work, see [the corresponding wiki
     page](https://gitlab.com/Lynnesbian/fif/-/wikis/Fix).
 ### Changed
+- The Minimum Supported Rust Version (MSRV) is now **1.48.0**.
 - Capped help output (`-h`/`--help`) width at 120 characters max
 - Output is now sorted by filename - specifically, errors will appear first, followed by files that fif is unable to 
   recommend an extension for, in order of filename, followed by files that fif knows how to rename, again in order 

Cargo.lock

@@ -175,7 +175,6 @@ checksum = "de853764b47027c2e862a995c34978ffa63c1501f2e15f987ba11bd4f9bba193"
 name = "fif"
 version = "0.3.7"
 dependencies = [
- "bitflags",
  "cfg-if",
  "clap",
  "clap_derive",
@@ -622,9 +621,9 @@ checksum = "533494a8f9b724d33625ab53c6c4800f7cc445895924a8ef649222dcb76e938b"
 
 [[package]]
 name = "smartstring"
-version = "0.2.7"
+version = "0.2.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "29620fe111ceaba7a50fd806b5f44c1ef44a697a739f6677a4464c7ea8685997"
+checksum = "31aa6a31c0c2b21327ce875f7e8952322acfcfd0c27569a6e18a647281352c9b"
 dependencies = [
  "static_assertions",
 ]

Cargo.toml

@@ -5,7 +5,7 @@ version = "0.3.7"
 authors = ["Lynnesbian <lynne@bune.city>"]
 edition = "2018"
 license = "GPL-3.0-or-later"
-rust-version = "1.43.0" # this can actually go as low as 1.41.0 after removing cached, but i'll leave it 1.43.0
+rust-version = "1.48.0" # this can actually go as low as 1.41.0 after removing cached, but i'll leave it 1.43.0
 repository = "https://gitlab.com/Lynnesbian/fif"
 readme = "README.md"
 keywords = ["mime", "mimetype", "utilities", "tools"]
@@ -35,7 +35,6 @@ cfg-if = "1.0.0"
 itertools = "0.10.0"
 serde = { version = "1.0", features = ["derive"], optional = true }
 serde_json = { version = "1.0", optional = true }
-bitflags = "~1.2.1" # 1.3+ requires Rust >= 1.46
 num_cpus = { version = "1.13.0", optional = true }
 maplit = "1.0.2"
 
@@ -54,11 +53,8 @@ infer = { version = "0.5.0", optional = true }
 # needs to be too. otherwise, fif won't work on platforms like powerpc, even though this dependency is the only
 # blocker -- fif runs just fine on powerpc without smartstring. or at least, just fine under qemu user-mode powerpc ~u0
 
-# additionally, smartstring 0.2.8 requires rust >=1.46 (due to https://github.com/rust-lang/rust/issues/49146), and
-# 0.2.3 doesn't impl Display on its SmartString type.
-# so, we need at least 0.2.4 so we can println! strings, and at most 0.2.7 until we bump the MSRV to at least 1.46.
-# see https://github.com/bodil/smartstring/blob/master/CHANGELOG.md
-smartstring = "<= 0.2.7, >= 0.2.4"
+# additionally, versions before 0.2.4 didn't impl Display, so we need at least that version for displaying Strings.
+smartstring = ">= 0.2.4"
 
 [dependencies.clap]
 # beta.4 requires rust >= 1.54.0 (and beta.3 was yanked)
@@ -90,4 +86,4 @@ opt-level = 3
 opt-level = 3
 
 [package.metadata]
-msrv = "1.43.0"
+msrv = "1.48.0"

README.md

@@ -7,7 +7,7 @@
 
 [![Version](https://img.shields.io/crates/v/fif.svg?logo=rust&style=flat-square)
 ](https://crates.io/crates/fif)
-[![Minimum Supported Rust Version](https://img.shields.io/badge/msrv-1.43.0-orange?logo=rust&style=flat-square)
+[![Minimum Supported Rust Version](https://img.shields.io/badge/msrv-1.48.0-orange?logo=rust&style=flat-square)
 ](https://gitlab.com/Lynnesbian/fif/-/blob/master/README.md#version-policy)
 [![License](https://img.shields.io/crates/l/fif.svg?style=flat-square)
 ](https://gitlab.com/Lynnesbian/fif/-/blob/master/LICENSE)

clippy.sh

@@ -23,6 +23,7 @@ for backend in "${_backends[@]}"; do
    -W clippy::pedantic \
    -W clippy::complexity \
    -W clippy::cargo \
+   -W clippy::style \
    -W clippy::float_cmp_const \
    -W clippy::lossy_float_literal \
    -W clippy::multiple_inherent_impl \
@@ -32,8 +33,6 @@ for backend in "${_backends[@]}"; do
    -A clippy::shadow_unrelated \
    -A clippy::option_if_let_else \
    -A clippy::multiple-crate-versions \
-   -A clippy::cast-possible-truncation \
-   -A clippy::cast-possible-wrap \
    -A clippy::must_use_candidate \
    -A clippy::missing_panics_doc \
    -A clippy::missing_errors_doc \
@@ -45,9 +44,7 @@ done
 # redundant_closure...: the alternative is often much more verbose
 # shadow_unrelated: sometimes things that seem unrelated are actually related ;)
 # option_if_let_else: the suggested code is usually harder to read than the original
-# multiple_crate_versions: cached uses an old version of hashbrown :c
-# cast_possible_truncation: only ever used where it would be totally fine
-# cast_possible_wrap: ditto
+# multiple_crate_versions: this doesn't actually trip right now, but it's not something i would want CI to fail over
 # must_use_candidate: useless
 # missing_panics_doc: the docs are just for me, fif isn't really intended to be used as a library, so this is unneeded
 # missing_errors_doc: ditto

clippy.toml

@@ -1,2 +1,3 @@
 # avoid-breaking-exported-api = false # only available on nightly for now
 cognitive-complexity-threshold = 15
+msrv = "1.48.0"

src/files.rs

@@ -249,9 +249,29 @@ pub fn mime_type<T: MimeDb>(db: &T, path: &Path) -> io::Result<Option<Mime>> {
 	let mut file = File::open(path)?;
 
 	// read a small amount to start with
-	file.read(&mut buffer)?;
 
-	let r = db.get_type(&buffer).filter(|mime|
+	let mut read = io::Result::Ok(0);
+
+	for _ in 0..3 {
+		// try to read the file up to 3 times, retrying if interrupted, bailing otherwise
+		file.seek(SeekFrom::Start(0))?;
+		read = file.read(&mut buffer);
+		match read {
+			Ok(_) => break,
+			Err(ref e) if e.kind() == io::ErrorKind::Interrupted => continue,
+			Err(_) => break,
+		}
+	}
+	
+	let read = read?;
+	let r = db.get_type(&buffer);
+
+	if read < INITIAL_BUF_SIZE {
+		// the file is smaller than INITIAL_BUF_SIZE - there's no point reading it again
+		return Ok(r);
+	}
+
+	let r = r.filter(|mime|
 		// some mime types should be investigated further, reading up to BUF_SIZE even if they've been determined already
 		// one such type is XML - there's many more specific types that can be determined by reading further (such as SVG)
 		mime != &mime::TEXT_XML
@@ -268,24 +288,17 @@ pub fn mime_type<T: MimeDb>(db: &T, path: &Path) -> io::Result<Option<Mime>> {
 		return Ok(r);
 	}
 
-	// attempt to read up to the BUF_SIZE bytes of the file.
-	// we've already read the first 128 bytes into a buffer, but i can't see an obvious way to reuse them in a way that's
-	// faster than simply moving the seek position back to the start of the file and re-reading the whole BUF_SIZE bytes.
-	// for example, reading (BUF_SIZE - INITIAL_BUF_SIZE) bytes, then concatenating the original INITIAL_BUF_SIZE buffer
-	// with this new one would presumably be faster - but it's not. i think it's more expensive to create the iterator,
-	// collect the contents, etc. i'll have to look into this more. i don't at all doubt that there IS a way to do this
-	// efficiently, and i can think of a way in principle, but i'm not sure how to express it in a way that is both
-	// idiomatic/safe and fast.
+	// attempt to read up to BUF_SIZE bytes of the file.
 	let mut buffer = [0; BUF_SIZE];
 	file.seek(SeekFrom::Start(0))?;
 	file.read(&mut buffer)?;
 	Ok(db.get_type(&buffer))
 }
 
-// Returns a list of known extensions for this mime type, if any.
-// This function uses the [Mime]'s "essence" rather than the [Mime] itself - mime_guess::get_mime_extensions ignores
-// the type suffix, treating "image/svg+xml" as "image/svg", and thus fails to find any extensions. Passing the
-// essence_str (which includes the suffix) fixes this.
+/// Returns a list of known extensions for this mime type, if any.
+/// This function uses the [`Mime`]'s "essence" rather than the [`Mime`] itself - [`mime_guess::get_mime_extensions`]
+/// ignores the type suffix, treating "image/svg+xml" as "image/svg", and thus fails to find any extensions. Passing the
+/// essence_str (which includes the suffix) fixes this.
 pub fn mime_extension_lookup(essence: String) -> Option<Vec<String>> {
 	if let Ok(cache) = MIMEXT.read() {
 		if let Some(exts) = cache.get(&essence) {

src/main.rs

@@ -40,7 +40,7 @@ fn main() {
 
 	let mut builder = env_logger::Builder::new();
 	builder
-		.filter_level(args.default_verbosity()) // set default log level
+		.filter_level(args.get_verbosity()) // set default log level
 		.parse_default_env() // set log level from RUST_LOG
 		.parse_env("FIF_LOG") // set log level from FIF_LOG
 		.format(|buf, r| {

src/parameters.rs

@@ -249,6 +249,7 @@ impl Parameters {
 		}
 	}
 
+	/// Populates a [`ScanOpts`] struct with values from [`self`].
 	pub const fn get_scan_opts(&self) -> ScanOpts {
 		ScanOpts {
 			hidden: self.scan_hidden,
@@ -258,10 +259,8 @@ impl Parameters {
 		}
 	}
 
-	pub fn default_verbosity(&self) -> log::LevelFilter {
-		#![allow(clippy::missing_const_for_fn)]
-		// match was not permitted inside const functions until 1.46
-
+	/// Gets the verbosity set by the user via the `-v` and `-q` flags.
+	pub const fn get_verbosity(&self) -> log::LevelFilter {
 		use log::LevelFilter;
 
 		match self.quiet {