1 files changed, 499 insertions, 0 deletions

diff --git a/crates/ra_assists/src/handlers/raw_string.rs b/crates/ra_assists/src/handlers/raw_string.rs
new file mode 100644
index 000000000..2c0a1e126
--- /dev/null
+++ b/crates/ra_assists/src/handlers/raw_string.rs
@@ -0,0 +1,499 @@
+use ra_syntax::{
+    ast, AstToken,
+    SyntaxKind::{RAW_STRING, STRING},
+    TextUnit,
+};
+
+use crate::{Assist, AssistCtx, AssistId};
+
+// Assist: make_raw_string
+//
+// Adds `r#` to a plain string literal.
+//
+// ```
+// fn main() {
+//     "Hello,<|> World!";
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     r#"Hello, World!"#;
+// }
+// ```
+pub(crate) fn make_raw_string(ctx: AssistCtx) -> Option<Assist> {
+    let token = ctx.find_token_at_offset(STRING).and_then(ast::String::cast)?;
+    let value = token.value()?;
+    ctx.add_assist(AssistId("make_raw_string"), "Rewrite as raw string", |edit| {
+        edit.target(token.syntax().text_range());
+        let max_hash_streak = count_hashes(&value);
+        let mut hashes = String::with_capacity(max_hash_streak + 1);
+        for _ in 0..hashes.capacity() {
+            hashes.push('#');
+        }
+        edit.replace(token.syntax().text_range(), format!("r{}\"{}\"{}", hashes, value, hashes));
+    })
+}
+
+// Assist: make_usual_string
+//
+// Turns a raw string into a plain string.
+//
+// ```
+// fn main() {
+//     r#"Hello,<|> "World!""#;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     "Hello, \"World!\"";
+// }
+// ```
+pub(crate) fn make_usual_string(ctx: AssistCtx) -> Option<Assist> {
+    let token = ctx.find_token_at_offset(RAW_STRING).and_then(ast::RawString::cast)?;
+    let value = token.value()?;
+    ctx.add_assist(AssistId("make_usual_string"), "Rewrite as regular string", |edit| {
+        edit.target(token.syntax().text_range());
+        // parse inside string to escape `"`
+        let escaped = value.escape_default().to_string();
+        edit.replace(token.syntax().text_range(), format!("\"{}\"", escaped));
+    })
+}
+
+// Assist: add_hash
+//
+// Adds a hash to a raw string literal.
+//
+// ```
+// fn main() {
+//     r#"Hello,<|> World!"#;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     r##"Hello, World!"##;
+// }
+// ```
+pub(crate) fn add_hash(ctx: AssistCtx) -> Option<Assist> {
+    let token = ctx.find_token_at_offset(RAW_STRING)?;
+    ctx.add_assist(AssistId("add_hash"), "Add # to raw string", |edit| {
+        edit.target(token.text_range());
+        edit.insert(token.text_range().start() + TextUnit::of_char('r'), "#");
+        edit.insert(token.text_range().end(), "#");
+    })
+}
+
+// Assist: remove_hash
+//
+// Removes a hash from a raw string literal.
+//
+// ```
+// fn main() {
+//     r#"Hello,<|> World!"#;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     r"Hello, World!";
+// }
+// ```
+pub(crate) fn remove_hash(ctx: AssistCtx) -> Option<Assist> {
+    let token = ctx.find_token_at_offset(RAW_STRING)?;
+    let text = token.text().as_str();
+    if text.starts_with("r\"") {
+        // no hash to remove
+        return None;
+    }
+    ctx.add_assist(AssistId("remove_hash"), "Remove hash from raw string", |edit| {
+        edit.target(token.text_range());
+        let result = &text[2..text.len() - 1];
+        let result = if result.starts_with('\"') {
+            // FIXME: this logic is wrong, not only the last has has to handled specially
+            // no more hash, escape
+            let internal_str = &result[1..result.len() - 1];
+            format!("\"{}\"", internal_str.escape_default().to_string())
+        } else {
+            result.to_owned()
+        };
+        edit.replace(token.text_range(), format!("r{}", result));
+    })
+}
+
+fn count_hashes(s: &str) -> usize {
+    let mut max_hash_streak = 0usize;
+    for idx in s.match_indices("\"#").map(|(i, _)| i) {
+        let (_, sub) = s.split_at(idx + 1);
+        let nb_hash = sub.chars().take_while(|c| *c == '#').count();
+        if nb_hash > max_hash_streak {
+            max_hash_streak = nb_hash;
+        }
+    }
+    max_hash_streak
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::helpers::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    #[test]
+    fn make_raw_string_target() {
+        check_assist_target(
+            make_raw_string,
+            r#"
+            fn f() {
+                let s = <|>"random\nstring";
+            }
+            "#,
+            r#""random\nstring""#,
+        );
+    }
+
+    #[test]
+    fn make_raw_string_works() {
+        check_assist(
+            make_raw_string,
+            r#"
+            fn f() {
+                let s = <|>"random\nstring";
+            }
+            "#,
+            r##"
+            fn f() {
+                let s = <|>r#"random
+string"#;
+            }
+            "##,
+        )
+    }
+
+    #[test]
+    fn make_raw_string_works_inside_macros() {
+        check_assist(
+            make_raw_string,
+            r#"
+            fn f() {
+                format!(<|>"x = {}", 92)
+            }
+            "#,
+            r##"
+            fn f() {
+                format!(<|>r#"x = {}"#, 92)
+            }
+            "##,
+        )
+    }
+
+    #[test]
+    fn make_raw_string_hashes_inside_works() {
+        check_assist(
+            make_raw_string,
+            r###"
+            fn f() {
+                let s = <|>"#random##\nstring";
+            }
+            "###,
+            r####"
+            fn f() {
+                let s = <|>r#"#random##
+string"#;
+            }
+            "####,
+        )
+    }
+
+    #[test]
+    fn make_raw_string_closing_hashes_inside_works() {
+        check_assist(
+            make_raw_string,
+            r###"
+            fn f() {
+                let s = <|>"#random\"##\nstring";
+            }
+            "###,
+            r####"
+            fn f() {
+                let s = <|>r###"#random"##
+string"###;
+            }
+            "####,
+        )
+    }
+
+    #[test]
+    fn make_raw_string_nothing_to_unescape_works() {
+        check_assist(
+            make_raw_string,
+            r#"
+            fn f() {
+                let s = <|>"random string";
+            }
+            "#,
+            r##"
+            fn f() {
+                let s = <|>r#"random string"#;
+            }
+            "##,
+        )
+    }
+
+    #[test]
+    fn make_raw_string_not_works_on_partial_string() {
+        check_assist_not_applicable(
+            make_raw_string,
+            r#"
+            fn f() {
+                let s = "foo<|>
+            }
+            "#,
+        )
+    }
+
+    #[test]
+    fn make_usual_string_not_works_on_partial_string() {
+        check_assist_not_applicable(
+            make_usual_string,
+            r#"
+            fn main() {
+                let s = r#"bar<|>
+            }
+            "#,
+        )
+    }
+
+    #[test]
+    fn add_hash_target() {
+        check_assist_target(
+            add_hash,
+            r#"
+            fn f() {
+                let s = <|>r"random string";
+            }
+            "#,
+            r#"r"random string""#,
+        );
+    }
+
+    #[test]
+    fn add_hash_works() {
+        check_assist(
+            add_hash,
+            r#"
+            fn f() {
+                let s = <|>r"random string";
+            }
+            "#,
+            r##"
+            fn f() {
+                let s = <|>r#"random string"#;
+            }
+            "##,
+        )
+    }
+
+    #[test]
+    fn add_more_hash_works() {
+        check_assist(
+            add_hash,
+            r##"
+            fn f() {
+                let s = <|>r#"random"string"#;
+            }
+            "##,
+            r###"
+            fn f() {
+                let s = <|>r##"random"string"##;
+            }
+            "###,
+        )
+    }
+
+    #[test]
+    fn add_hash_not_works() {
+        check_assist_not_applicable(
+            add_hash,
+            r#"
+            fn f() {
+                let s = <|>"random string";
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn remove_hash_target() {
+        check_assist_target(
+            remove_hash,
+            r##"
+            fn f() {
+                let s = <|>r#"random string"#;
+            }
+            "##,
+            r##"r#"random string"#"##,
+        );
+    }
+
+    #[test]
+    fn remove_hash_works() {
+        check_assist(
+            remove_hash,
+            r##"
+            fn f() {
+                let s = <|>r#"random string"#;
+            }
+            "##,
+            r#"
+            fn f() {
+                let s = <|>r"random string";
+            }
+            "#,
+        )
+    }
+
+    #[test]
+    fn remove_hash_with_quote_works() {
+        check_assist(
+            remove_hash,
+            r##"
+            fn f() {
+                let s = <|>r#"random"str"ing"#;
+            }
+            "##,
+            r#"
+            fn f() {
+                let s = <|>r"random\"str\"ing";
+            }
+            "#,
+        )
+    }
+
+    #[test]
+    fn remove_more_hash_works() {
+        check_assist(
+            remove_hash,
+            r###"
+            fn f() {
+                let s = <|>r##"random string"##;
+            }
+            "###,
+            r##"
+            fn f() {
+                let s = <|>r#"random string"#;
+            }
+            "##,
+        )
+    }
+
+    #[test]
+    fn remove_hash_not_works() {
+        check_assist_not_applicable(
+            remove_hash,
+            r#"
+            fn f() {
+                let s = <|>"random string";
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn remove_hash_no_hash_not_works() {
+        check_assist_not_applicable(
+            remove_hash,
+            r#"
+            fn f() {
+                let s = <|>r"random string";
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn make_usual_string_target() {
+        check_assist_target(
+            make_usual_string,
+            r##"
+            fn f() {
+                let s = <|>r#"random string"#;
+            }
+            "##,
+            r##"r#"random string"#"##,
+        );
+    }
+
+    #[test]
+    fn make_usual_string_works() {
+        check_assist(
+            make_usual_string,
+            r##"
+            fn f() {
+                let s = <|>r#"random string"#;
+            }
+            "##,
+            r#"
+            fn f() {
+                let s = <|>"random string";
+            }
+            "#,
+        )
+    }
+
+    #[test]
+    fn make_usual_string_with_quote_works() {
+        check_assist(
+            make_usual_string,
+            r##"
+            fn f() {
+                let s = <|>r#"random"str"ing"#;
+            }
+            "##,
+            r#"
+            fn f() {
+                let s = <|>"random\"str\"ing";
+            }
+            "#,
+        )
+    }
+
+    #[test]
+    fn make_usual_string_more_hash_works() {
+        check_assist(
+            make_usual_string,
+            r###"
+            fn f() {
+                let s = <|>r##"random string"##;
+            }
+            "###,
+            r##"
+            fn f() {
+                let s = <|>"random string";
+            }
+            "##,
+        )
+    }
+
+    #[test]
+    fn make_usual_string_not_works() {
+        check_assist_not_applicable(
+            make_usual_string,
+            r#"
+            fn f() {
+                let s = <|>"random string";
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn count_hashes_test() {
+        assert_eq!(0, count_hashes("abc"));
+        assert_eq!(0, count_hashes("###"));
+        assert_eq!(1, count_hashes("\"#abc"));
+        assert_eq!(0, count_hashes("#abc"));
+        assert_eq!(2, count_hashes("#ab\"##c"));
+        assert_eq!(4, count_hashes("#ab\"##\"####c"));
+    }
+}