hlssink3: Use sprintf for segment name formatting

The zero-padded naming requirement is unnecessary. Use simple
sprintf instead

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1387>

4 files changed, 17 insertions, 129 deletions

diff --git a/Cargo.lock b/Cargo.lock
index d711f1409..1c84535e7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2227,7 +2227,7 @@ dependencies = [
  "gstreamer-check",
  "m3u8-rs",
  "once_cell",
- "regex",
+ "sprintf",
 ]
 
 [[package]]
@@ -5334,6 +5334,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "sprintf"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c0cdea5a20a06e7c57f627094e7b1618e5665592cd88f2d45fa4014e348db58"
+
+[[package]]
 name = "strength_reduce"
 version = "0.2.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/net/hlssink3/Cargo.toml b/net/hlssink3/Cargo.toml
index d3f8ae0a6..bdba7923c 100644
--- a/net/hlssink3/Cargo.toml
+++ b/net/hlssink3/Cargo.toml
@@ -15,7 +15,7 @@ glib = { git = "https://github.com/gtk-rs/gtk-rs-core", branch = "0.16", version
 gio = { git = "https://github.com/gtk-rs/gtk-rs-core", branch = "0.16", version = "0.16" }
 once_cell = "1.7.2"
 m3u8-rs = "5.0"
-regex = "1"
+sprintf = "0.1.3"
 
 [dev-dependencies]
 gst-audio = { package = "gstreamer-audio", git = "https://gitlab.freedesktop.org/gstreamer/gstreamer-rs", branch = "0.19", version = "0.19" }
diff --git a/net/hlssink3/src/imp.rs b/net/hlssink3/src/imp.rs
index 9f4492701..f9737afaf 100644
--- a/net/hlssink3/src/imp.rs
+++ b/net/hlssink3/src/imp.rs
@@ -6,7 +6,7 @@
 //
 // SPDX-License-Identifier: MPL-2.0
 
-use crate::playlist::{Playlist, SegmentFormatter};
+use crate::playlist::Playlist;
 use crate::HlsSink3PlaylistType;
 use gio::prelude::*;
 use glib::subclass::prelude::*;
@@ -60,7 +60,6 @@ impl From<Option<&MediaPlaylistType>> for HlsSink3PlaylistType {
 
 struct Settings {
     location: String,
-    segment_formatter: SegmentFormatter,
     playlist_location: String,
     playlist_root: Option<String>,
     playlist_length: u32,
@@ -88,7 +87,6 @@ impl Default for Settings {
             .expect("Could not make element giostreamsink");
         Self {
             location: String::from(DEFAULT_LOCATION),
-            segment_formatter: SegmentFormatter::new(DEFAULT_LOCATION).unwrap(),
             playlist_location: String::from(DEFAULT_PLAYLIST_LOCATION),
             playlist_root: None,
             playlist_length: DEFAULT_PLAYLIST_LENGTH,
@@ -190,7 +188,14 @@ impl HlsSink3 {
         };
 
         let settings = self.settings.lock().unwrap();
-        let segment_file_location = settings.segment_formatter.segment(fragment_id);
+        let segment_file_location = match sprintf::sprintf!(&settings.location, fragment_id) {
+            Ok(file_name) => file_name,
+            Err(err) => {
+                gst::error!(CAT, imp: self, "Couldn't build file name, err: {:?}", err,);
+                return Err(String::from("Invalid init segment file pattern"));
+            }
+        };
+
         gst::trace!(
             CAT,
             imp: self,
@@ -493,9 +498,6 @@ impl ObjectImpl for HlsSink3 {
                     .get::<Option<String>>()
                     .expect("type checked upstream")
                     .unwrap_or_else(|| DEFAULT_LOCATION.into());
-                settings.segment_formatter = SegmentFormatter::new(&settings.location).expect(
-                    "A string containing `%03d` pattern must be used (can be any number from 0-9)",
-                );
                 settings
                     .splitmuxsink
                     .set_property("location", &settings.location);
diff --git a/net/hlssink3/src/playlist.rs b/net/hlssink3/src/playlist.rs
index ee3297eb0..a541b3187 100644
--- a/net/hlssink3/src/playlist.rs
+++ b/net/hlssink3/src/playlist.rs
@@ -7,15 +7,11 @@
 // SPDX-License-Identifier: MPL-2.0
 
 use m3u8_rs::{MediaPlaylist, MediaPlaylistType, MediaSegment};
-use once_cell::sync::Lazy;
-use regex::Regex;
 use std::io::Write;
 
 const GST_M3U8_PLAYLIST_V3: usize = 3;
 const GST_M3U8_PLAYLIST_V4: usize = 4;
 
-static SEGMENT_IDX_PATTERN: Lazy<regex::Regex> = Lazy::new(|| Regex::new(r"(%0(\d+)d)").unwrap());
-
 /// An HLS playlist.
 ///
 /// Controls the changes that needs to happen in the playlist as new segments are added. This
@@ -155,119 +151,3 @@ pub enum PlaylistRenderState {
     Init,
     Started,
 }
-
-/// A formatter for segment locations.
-///
-/// The formatting is based on a string that must contain the placeholder `%0Xd` where `X` is a
-/// the number of zero prefixes you want to have in the segment name. The placeholder is only
-/// replaced once in the string, other placements are not going to be processed.
-///
-/// # Examples
-///
-/// In this example we want to have segment files with the following names:
-/// ```text
-/// part001.ts
-/// part002.ts
-/// part003.ts
-/// part004.ts
-/// ```
-/// Then we can use the segment pattern value as `"part%03d.ts"`:
-///
-/// ```rust,ignore
-/// let formatter = SegmentFormatter::new("part%03d.ts").unwrap();
-/// assert_eq!(formatter.segment(1), "part001.ts");
-/// assert_eq!(formatter.segment(2), "part002.ts");
-/// assert_eq!(formatter.segment(3), "part003.ts");
-/// assert_eq!(formatter.segment(4), "part004.ts");
-/// ```
-pub struct SegmentFormatter {
-    prefix: String,
-    suffix: String,
-    padding_len: u32,
-}
-
-impl SegmentFormatter {
-    /// Processes the segment name containing a placeholder. It can be used
-    /// repeatedly to format segment names.
-    ///
-    /// If an invalid placeholder is provided, then `None` is returned.
-    pub fn new<S: AsRef<str>>(segment_pattern: S) -> Option<Self> {
-        let segment_pattern = segment_pattern.as_ref();
-        let caps = SEGMENT_IDX_PATTERN.captures(segment_pattern)?;
-        let number_placement_match = caps.get(1)?;
-        let zero_pad_match = caps.get(2)?;
-        let padding_len = zero_pad_match
-            .as_str()
-            .parse::<u32>()
-            .expect("valid number matched by regex");
-        let prefix = segment_pattern[..number_placement_match.start()].to_string();
-        let suffix = segment_pattern[number_placement_match.end()..].to_string();
-        Some(Self {
-            prefix,
-            suffix,
-            padding_len,
-        })
-    }
-
-    /// Returns the segment location formatted for the provided id.
-    #[inline]
-    pub fn segment(&self, id: u32) -> String {
-        let padded_number = left_pad_zeroes(self.padding_len, id);
-        format!("{}{}{}", self.prefix, padded_number, self.suffix)
-    }
-}
-
-/// Transforms a number to a zero padded string representation.
-///
-/// The zero padding is added to the left of the number which is converted to a string. For the
-/// case that the length number converted to string is larger than the requested padding, the
-/// number representation is returned and no padding is added. The length of the returned string is
-/// the maximum value between the desired padding and the length of the number.
-///
-/// # Examples
-///
-/// ```rust,ignore
-/// let padded_number = left_pad_zeroes(4, 10);
-/// assert_eq!(padded_number, "0010");
-/// ```
-#[inline]
-pub(crate) fn left_pad_zeroes(padding: u32, number: u32) -> String {
-    let numerical_repr = number.to_string();
-    let mut padded = String::with_capacity(padding.max(numerical_repr.len() as u32) as usize);
-    let pad_zeroes = padding as i32 - numerical_repr.len() as i32;
-    if pad_zeroes > 0 {
-        for _ in 0..pad_zeroes {
-            padded.push('0');
-        }
-    }
-    padded.push_str(&numerical_repr);
-    padded
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn segment_is_correctly_formatted() {
-        let formatter = SegmentFormatter::new("segment%05d.ts").unwrap();
-
-        assert_eq!("segment00001.ts", formatter.segment(1));
-        assert_eq!("segment00016.ts", formatter.segment(16));
-        assert_eq!("segment01827.ts", formatter.segment(1827));
-        assert_eq!("segment98765.ts", formatter.segment(98765));
-
-        let formatter = SegmentFormatter::new("part-%03d.ts").unwrap();
-        assert_eq!("part-010.ts", formatter.segment(10));
-        assert_eq!("part-9999.ts", formatter.segment(9999));
-    }
-
-    #[test]
-    fn padding_numbers() {
-        assert_eq!("001", left_pad_zeroes(3, 1));
-        assert_eq!("010", left_pad_zeroes(3, 10));
-        assert_eq!("100", left_pad_zeroes(3, 100));
-        assert_eq!("1000", left_pad_zeroes(3, 1000));
-        assert_eq!("987654321", left_pad_zeroes(3, 987654321));
-    }
-}