Add ability to copy a permalink to a line (#7119)

This PR adds the ability to copy the permalink to a line from within
Zed.

This functionality is available through the `editor: copy permalink to
line` action in the command palette:

<img width="589" alt="Screenshot 2024-01-30 at 7 07 46 PM"
src="https://github.com/zed-industries/zed/assets/1486634/332282cb-211f-4f16-9eb1-415bcfee9b7b">

Executing this action will create a permalink to the currently selected
line(s) and copy it to the clipboard.

Here is an example line:

```
56c80e8011/src/lib.rs (L25)
```

Currently, both GitHub and GitLab are supported.

### Notes and known limitations

- In order to determine where to permalink to, we read the URL of the
`origin` remote in Git. This feature will not work if the `origin`
remote is not present.
- Attempting to permalink to a ref that is not pushed to the origin will
result in the link 404ing.
- Attempting to permalink when Git is in a dirty state may not generate
the right link.
- For instance, modifying a file (e.g., adding new lines) and grabbing a
permalink to it will result in incorrect line numbers.

Release Notes:

- Added the ability to copy a permalink to a line
([#6777](https://github.com/zed-industries/zed/issues/6777)).
- Available via the `editor: copy permalink to line` action in the
command palette.

crates/editor/src/git/permalink.rs

@@ -0,0 +1,288 @@
+use std::ops::Range;
+
+use anyhow::{anyhow, Result};
+use language::Point;
+use url::Url;
+
+enum GitHostingProvider {
+    Github,
+    Gitlab,
+}
+
+impl GitHostingProvider {
+    fn base_url(&self) -> Url {
+        let base_url = match self {
+            Self::Github => "https://github.com",
+            Self::Gitlab => "https://gitlab.com",
+        };
+
+        Url::parse(&base_url).unwrap()
+    }
+
+    /// Returns the fragment portion of the URL for the selected lines in
+    /// the representation the [`GitHostingProvider`] expects.
+    fn line_fragment(&self, selection: &Range<Point>) -> String {
+        if selection.start.row == selection.end.row {
+            let line = selection.start.row + 1;
+
+            match self {
+                Self::Github | Self::Gitlab => format!("L{}", line),
+            }
+        } else {
+            let start_line = selection.start.row + 1;
+            let end_line = selection.end.row + 1;
+
+            match self {
+                Self::Github => format!("L{}-L{}", start_line, end_line),
+                Self::Gitlab => format!("L{}-{}", start_line, end_line),
+            }
+        }
+    }
+}
+
+pub struct BuildPermalinkParams<'a> {
+    pub remote_url: &'a str,
+    pub sha: &'a str,
+    pub path: &'a str,
+    pub selection: Option<Range<Point>>,
+}
+
+pub fn build_permalink(params: BuildPermalinkParams) -> Result<Url> {
+    let BuildPermalinkParams {
+        remote_url,
+        sha,
+        path,
+        selection,
+    } = params;
+
+    let ParsedGitRemote {
+        provider,
+        owner,
+        repo,
+    } = parse_git_remote_url(remote_url)
+        .ok_or_else(|| anyhow!("failed to parse Git remote URL"))?;
+
+    let path = match provider {
+        GitHostingProvider::Github => format!("{owner}/{repo}/blob/{sha}/{path}"),
+        GitHostingProvider::Gitlab => format!("{owner}/{repo}/-/blob/{sha}/{path}"),
+    };
+    let line_fragment = selection.map(|selection| provider.line_fragment(&selection));
+
+    let mut permalink = provider.base_url().join(&path).unwrap();
+    permalink.set_fragment(line_fragment.as_deref());
+
+    Ok(permalink)
+}
+
+struct ParsedGitRemote<'a> {
+    pub provider: GitHostingProvider,
+    pub owner: &'a str,
+    pub repo: &'a str,
+}
+
+fn parse_git_remote_url(url: &str) -> Option<ParsedGitRemote> {
+    if url.starts_with("git@github.com:") || url.starts_with("https://github.com/") {
+        let repo_with_owner = url
+            .trim_start_matches("git@github.com:")
+            .trim_start_matches("https://github.com/")
+            .trim_end_matches(".git");
+
+        let (owner, repo) = repo_with_owner.split_once("/")?;
+
+        return Some(ParsedGitRemote {
+            provider: GitHostingProvider::Github,
+            owner,
+            repo,
+        });
+    }
+
+    if url.starts_with("git@gitlab.com:") || url.starts_with("https://gitlab.com/") {
+        let repo_with_owner = url
+            .trim_start_matches("git@gitlab.com:")
+            .trim_start_matches("https://gitlab.com/")
+            .trim_end_matches(".git");
+
+        let (owner, repo) = repo_with_owner.split_once("/")?;
+
+        return Some(ParsedGitRemote {
+            provider: GitHostingProvider::Gitlab,
+            owner,
+            repo,
+        });
+    }
+
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_build_github_permalink_from_ssh_url() {
+        let permalink = build_permalink(BuildPermalinkParams {
+            remote_url: "git@github.com:zed-industries/zed.git",
+            sha: "e6ebe7974deb6bb6cc0e2595c8ec31f0c71084b7",
+            path: "crates/editor/src/git/permalink.rs",
+            selection: None,
+        })
+        .unwrap();
+
+        let expected_url = "https://github.com/zed-industries/zed/blob/e6ebe7974deb6bb6cc0e2595c8ec31f0c71084b7/crates/editor/src/git/permalink.rs";
+        assert_eq!(permalink.to_string(), expected_url.to_string())
+    }
+
+    #[test]
+    fn test_build_github_permalink_from_ssh_url_single_line_selection() {
+        let permalink = build_permalink(BuildPermalinkParams {
+            remote_url: "git@github.com:zed-industries/zed.git",
+            sha: "e6ebe7974deb6bb6cc0e2595c8ec31f0c71084b7",
+            path: "crates/editor/src/git/permalink.rs",
+            selection: Some(Point::new(6, 1)..Point::new(6, 10)),
+        })
+        .unwrap();
+
+        let expected_url = "https://github.com/zed-industries/zed/blob/e6ebe7974deb6bb6cc0e2595c8ec31f0c71084b7/crates/editor/src/git/permalink.rs#L7";
+        assert_eq!(permalink.to_string(), expected_url.to_string())
+    }
+
+    #[test]
+    fn test_build_github_permalink_from_ssh_url_multi_line_selection() {
+        let permalink = build_permalink(BuildPermalinkParams {
+            remote_url: "git@github.com:zed-industries/zed.git",
+            sha: "e6ebe7974deb6bb6cc0e2595c8ec31f0c71084b7",
+            path: "crates/editor/src/git/permalink.rs",
+            selection: Some(Point::new(23, 1)..Point::new(47, 10)),
+        })
+        .unwrap();
+
+        let expected_url = "https://github.com/zed-industries/zed/blob/e6ebe7974deb6bb6cc0e2595c8ec31f0c71084b7/crates/editor/src/git/permalink.rs#L24-L48";
+        assert_eq!(permalink.to_string(), expected_url.to_string())
+    }
+
+    #[test]
+    fn test_build_github_permalink_from_https_url() {
+        let permalink = build_permalink(BuildPermalinkParams {
+            remote_url: "https://github.com/zed-industries/zed.git",
+            sha: "b2efec9824c45fcc90c9a7eb107a50d1772a60aa",
+            path: "crates/zed/src/main.rs",
+            selection: None,
+        })
+        .unwrap();
+
+        let expected_url = "https://github.com/zed-industries/zed/blob/b2efec9824c45fcc90c9a7eb107a50d1772a60aa/crates/zed/src/main.rs";
+        assert_eq!(permalink.to_string(), expected_url.to_string())
+    }
+
+    #[test]
+    fn test_build_github_permalink_from_https_url_single_line_selection() {
+        let permalink = build_permalink(BuildPermalinkParams {
+            remote_url: "https://github.com/zed-industries/zed.git",
+            sha: "b2efec9824c45fcc90c9a7eb107a50d1772a60aa",
+            path: "crates/zed/src/main.rs",
+            selection: Some(Point::new(6, 1)..Point::new(6, 10)),
+        })
+        .unwrap();
+
+        let expected_url = "https://github.com/zed-industries/zed/blob/b2efec9824c45fcc90c9a7eb107a50d1772a60aa/crates/zed/src/main.rs#L7";
+        assert_eq!(permalink.to_string(), expected_url.to_string())
+    }
+
+    #[test]
+    fn test_build_github_permalink_from_https_url_multi_line_selection() {
+        let permalink = build_permalink(BuildPermalinkParams {
+            remote_url: "https://github.com/zed-industries/zed.git",
+            sha: "b2efec9824c45fcc90c9a7eb107a50d1772a60aa",
+            path: "crates/zed/src/main.rs",
+            selection: Some(Point::new(23, 1)..Point::new(47, 10)),
+        })
+        .unwrap();
+
+        let expected_url = "https://github.com/zed-industries/zed/blob/b2efec9824c45fcc90c9a7eb107a50d1772a60aa/crates/zed/src/main.rs#L24-L48";
+        assert_eq!(permalink.to_string(), expected_url.to_string())
+    }
+
+    #[test]
+    fn test_build_gitlab_permalink_from_ssh_url() {
+        let permalink = build_permalink(BuildPermalinkParams {
+            remote_url: "git@gitlab.com:zed-industries/zed.git",
+            sha: "e6ebe7974deb6bb6cc0e2595c8ec31f0c71084b7",
+            path: "crates/editor/src/git/permalink.rs",
+            selection: None,
+        })
+        .unwrap();
+
+        let expected_url = "https://gitlab.com/zed-industries/zed/-/blob/e6ebe7974deb6bb6cc0e2595c8ec31f0c71084b7/crates/editor/src/git/permalink.rs";
+        assert_eq!(permalink.to_string(), expected_url.to_string())
+    }
+
+    #[test]
+    fn test_build_gitlab_permalink_from_ssh_url_single_line_selection() {
+        let permalink = build_permalink(BuildPermalinkParams {
+            remote_url: "git@gitlab.com:zed-industries/zed.git",
+            sha: "e6ebe7974deb6bb6cc0e2595c8ec31f0c71084b7",
+            path: "crates/editor/src/git/permalink.rs",
+            selection: Some(Point::new(6, 1)..Point::new(6, 10)),
+        })
+        .unwrap();
+
+        let expected_url = "https://gitlab.com/zed-industries/zed/-/blob/e6ebe7974deb6bb6cc0e2595c8ec31f0c71084b7/crates/editor/src/git/permalink.rs#L7";
+        assert_eq!(permalink.to_string(), expected_url.to_string())
+    }
+
+    #[test]
+    fn test_build_gitlab_permalink_from_ssh_url_multi_line_selection() {
+        let permalink = build_permalink(BuildPermalinkParams {
+            remote_url: "git@gitlab.com:zed-industries/zed.git",
+            sha: "e6ebe7974deb6bb6cc0e2595c8ec31f0c71084b7",
+            path: "crates/editor/src/git/permalink.rs",
+            selection: Some(Point::new(23, 1)..Point::new(47, 10)),
+        })
+        .unwrap();
+
+        let expected_url = "https://gitlab.com/zed-industries/zed/-/blob/e6ebe7974deb6bb6cc0e2595c8ec31f0c71084b7/crates/editor/src/git/permalink.rs#L24-48";
+        assert_eq!(permalink.to_string(), expected_url.to_string())
+    }
+
+    #[test]
+    fn test_build_gitlab_permalink_from_https_url() {
+        let permalink = build_permalink(BuildPermalinkParams {
+            remote_url: "https://gitlab.com/zed-industries/zed.git",
+            sha: "b2efec9824c45fcc90c9a7eb107a50d1772a60aa",
+            path: "crates/zed/src/main.rs",
+            selection: None,
+        })
+        .unwrap();
+
+        let expected_url = "https://gitlab.com/zed-industries/zed/-/blob/b2efec9824c45fcc90c9a7eb107a50d1772a60aa/crates/zed/src/main.rs";
+        assert_eq!(permalink.to_string(), expected_url.to_string())
+    }
+
+    #[test]
+    fn test_build_gitlab_permalink_from_https_url_single_line_selection() {
+        let permalink = build_permalink(BuildPermalinkParams {
+            remote_url: "https://gitlab.com/zed-industries/zed.git",
+            sha: "b2efec9824c45fcc90c9a7eb107a50d1772a60aa",
+            path: "crates/zed/src/main.rs",
+            selection: Some(Point::new(6, 1)..Point::new(6, 10)),
+        })
+        .unwrap();
+
+        let expected_url = "https://gitlab.com/zed-industries/zed/-/blob/b2efec9824c45fcc90c9a7eb107a50d1772a60aa/crates/zed/src/main.rs#L7";
+        assert_eq!(permalink.to_string(), expected_url.to_string())
+    }
+
+    #[test]
+    fn test_build_gitlab_permalink_from_https_url_multi_line_selection() {
+        let permalink = build_permalink(BuildPermalinkParams {
+            remote_url: "https://gitlab.com/zed-industries/zed.git",
+            sha: "b2efec9824c45fcc90c9a7eb107a50d1772a60aa",
+            path: "crates/zed/src/main.rs",
+            selection: Some(Point::new(23, 1)..Point::new(47, 10)),
+        })
+        .unwrap();
+
+        let expected_url = "https://gitlab.com/zed-industries/zed/-/blob/b2efec9824c45fcc90c9a7eb107a50d1772a60aa/crates/zed/src/main.rs#L24-48";
+        assert_eq!(permalink.to_string(), expected_url.to_string())
+    }
+}