add some text helpers

2020-01-10 21:01:23 +10:00 · 2020-01-10 21:01:23 +10:00 · d4553e9488
commit d4553e9488
parent 96c8784024
2 changed files with 99 additions and 0 deletions
--- a/rslib/src/lib.rs
+++ b/rslib/src/lib.rs
@ -7,3 +7,4 @@ pub mod backend;
 pub mod err;
 pub mod sched;
 pub mod template;
+pub mod text;
--- a/rslib/src/text.rs
+++ b/rslib/src/text.rs
@ -0,0 +1,98 @@
+// Copyright: Ankitects Pty Ltd and contributors
+// License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
+
+use lazy_static::lazy_static;
+use regex::Regex;
+use std::borrow::Cow;
+use std::collections::HashSet;
+use std::ptr;
+
+lazy_static! {
+    static ref HTML: Regex = Regex::new(concat!(
+        "(?si)",
+        // wrapped text
+        r"(<!--.*?-->)|(<style.*?>.*?</style>)|(<script.*?>.*?</script>)",
+        // html tags
+        r"|(<.*?>)",
+    ))
+    .unwrap();
+
+    static ref IMG_TAG: Regex = Regex::new(
+        // group 1 is filename
+        r#"(?i)<img[^>]+src=["']?([^"'>]+)["']?[^>]*>"#
+    ).unwrap();
+
+    static ref SOUND_TAG: Regex = Regex::new(
+        r"\[sound:(.*?)\]"
+    ).unwrap();
+
+    static ref CLOZED_TEXT: Regex = Regex::new(
+        r"(?s)\{\{c(\d+)::.+?\}\}"
+    ).unwrap();
+}
+
+pub fn strip_html(html: &str) -> Cow<str> {
+    HTML.replace_all(html, "")
+}
+
+pub fn strip_sounds(html: &str) -> Cow<str> {
+    SOUND_TAG.replace_all(html, "")
+}
+
+pub fn strip_html_preserving_image_filenames(html: &str) -> Cow<str> {
+    let without_fnames = IMG_TAG.replace_all(html, r" $1 ");
+    let without_html = HTML.replace_all(&without_fnames, "");
+    // no changes?
+    if let Cow::Borrowed(b) = without_html {
+        if ptr::eq(b, html) {
+            return Cow::Borrowed(html);
+        }
+    }
+    // make borrow checker happy
+    without_html.into_owned().into()
+}
+
+pub fn cloze_numbers_in_string(html: &str) -> HashSet<u16> {
+    let mut hash = HashSet::with_capacity(4);
+    for cap in CLOZED_TEXT.captures_iter(html) {
+        if let Ok(n) = cap[1].parse() {
+            hash.insert(n);
+        }
+    }
+    hash
+}
+
+#[cfg(test)]
+mod test {
+    use crate::text::{cloze_numbers_in_string, strip_html, strip_html_preserving_image_filenames};
+    use std::collections::HashSet;
+
+    #[test]
+    fn test_stripping() {
+        assert_eq!(strip_html("test"), "test");
+        assert_eq!(strip_html("t<b>e</b>st"), "test");
+        assert_eq!(strip_html("so<SCRIPT>t<b>e</b>st</script>me"), "some");
+
+        assert_eq!(
+            strip_html_preserving_image_filenames("<img src=foo.jpg>"),
+            " foo.jpg "
+        );
+        assert_eq!(
+            strip_html_preserving_image_filenames("<img src='foo.jpg'><html>"),
+            " foo.jpg "
+        );
+        assert_eq!(strip_html_preserving_image_filenames("<html>"), "");
+    }
+
+    #[test]
+    fn test_cloze() {
+        assert_eq!(
+            cloze_numbers_in_string("test"),
+            vec![].into_iter().collect::<HashSet<u16>>()
+        );
+        assert_eq!(
+            cloze_numbers_in_string("{{c2::te}}{{c1::s}}t{{"),
+            vec![1, 2].into_iter().collect::<HashSet<u16>>()
+        );
+    }
+}