Correct line folding in from ics/from vcf (#10577)

# Description
Potential fix for #10398

datatracker.ietf.org/doc/html/rfc5545#section-3.1
datatracker.ietf.org/doc/html/rfc6350#section-3.2

---------

Co-authored-by: Joerg <joerg@schuetter.org>

crates/nu_plugin_formats/src/from/ics.rs

@@ -14,9 +14,17 @@ pub fn from_ics_call(call: &EvaluatedCall, input: &Value) -> Result<Value, Label
 
     let input_string = input_string
         .lines()
-        .map(|x| x.trim().to_string())
+        .enumerate()
-        .collect::<Vec<_>>()
+        .map(|(i, x)| {
-        .join("\n");
+            if i == 0 {
+                x.trim().to_string()
+            } else if x.len() > 1 && (x.starts_with(' ') || x.starts_with('\t')) {
+                x[1..].trim_end().to_string()
+            } else {
+                format!("\n{}", x.trim())
+            }
+        })
+        .collect::<String>();
 
     let input_bytes = input_string.as_bytes();
     let buf_reader = BufReader::new(input_bytes);

crates/nu_plugin_formats/src/from/vcf.rs

@@ -13,9 +13,17 @@ pub fn from_vcf_call(call: &EvaluatedCall, input: &Value) -> Result<Value, Label
 
     let input_string = input_string
         .lines()
-        .map(|x| x.trim().to_string())
+        .enumerate()
-        .collect::<Vec<_>>()
+        .map(|(i, x)| {
-        .join("\n");
+            if i == 0 {
+                x.trim().to_string()
+            } else if x.len() > 1 && (x.starts_with(' ') || x.starts_with('\t')) {
+                x[1..].trim_end().to_string()
+            } else {
+                format!("\n{}", x.trim())
+            }
+        })
+        .collect::<String>();
 
     let input_bytes = input_string.as_bytes();
     let cursor = std::io::Cursor::new(input_bytes);

tests/plugins/formats/ics.rs

@@ -1,4 +1,4 @@
-use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::fs::Stub::{FileWithContent, FileWithContentToBeTrimmed};
 use nu_test_support::nu_with_plugins;
 use nu_test_support::playground::Playground;
 use pretty_assertions::assert_eq;
@@ -98,3 +98,47 @@ fn from_ics_text_to_table() {
         assert_eq!(actual.out, "Maryland Game");
     })
 }
+
+#[test]
+fn from_ics_text_with_linebreak_to_table() {
+    Playground::setup("filter_from_ics_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "calendar.txt",
+            r#"BEGIN:VCALENDAR
+BEGIN:VEVENT
+DTSTART:20171007T200000Z
+DTEND:20171007T233000Z
+DTSTAMP:20200319T182138Z
+UID:4l80f6dcovnriq38g57g07btid@google.com
+CREATED:20170719T202915Z
+DESCRIPTION:
+LAST-MODIFIED:20170930T190808Z
+LOCATION:The Restaurant n
+ ear the
+  Belltower
+SEQUENCE:1
+STATUS:CONFIRMED
+SUMMARY:Dinner
+TRANSP:TRANSPARENT
+END:VEVENT
+END:VCALENDAR"#,
+        )]);
+
+        let cwd = dirs.test();
+        let actual = nu_with_plugins!(
+            cwd: cwd,
+            plugin: ("nu_plugin_formats"),
+            r#"
+                open calendar.txt
+                | from ics
+                | get events.0
+                | get properties.0
+                | where name == "LOCATION"
+                | first
+                | get value
+            "#
+        );
+
+        assert_eq!(actual.out, "The Restaurant near the Belltower");
+    })
+}

tests/plugins/formats/vcf.rs

@@ -1,4 +1,4 @@
-use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::fs::Stub::{FileWithContent, FileWithContentToBeTrimmed};
 use nu_test_support::nu_with_plugins;
 use nu_test_support::playground::Playground;
 use pretty_assertions::assert_eq;
@@ -82,3 +82,42 @@ fn from_vcf_text_to_table() {
         assert_eq!(actual.out, "john.doe99@gmail.com");
     })
 }
+
+#[test]
+fn from_vcf_text_with_linebreak_to_table() {
+    Playground::setup("filter_from_vcf_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "contacts.txt",
+            r"BEGIN:VCARD
+VERSION:3.0
+FN:John Doe
+N:Doe;John;;;
+EMAIL;TYPE=INTERNET:john.doe99
+ @gmail.com
+item1.ORG:'Alpine Ski Resort'
+item1.X-ABLabel:Other
+item2.TITLE:'Ski Instructor'
+item2.X-ABLabel:Other
+BDAY:19001106
+NOTE:Facebook: john.doe.3\nWebsite: \nHometown: Cleveland\, Ohio
+CATEGORIES:myContacts
+END:VCARD",
+        )]);
+
+        let cwd = dirs.test();
+        let actual = nu_with_plugins!(
+            cwd: cwd,
+            plugin: ("nu_plugin_formats"),
+            r#"
+                open contacts.txt
+                | from vcf
+                | get properties.0
+                | where name == "EMAIL"
+                | first
+                | get value
+            "#
+        );
+
+        assert_eq!(actual.out, "john.doe99@gmail.com");
+    })
+}