stelae 0.2.0

A collection of tools in Rust and Python for preserving, authenticating, and accessing laws in perpetuity.
Documentation 
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//! The git module contains structs for interacting with git repositories
//! in the Stelae Library.
use anyhow::Context;
use git2::Repository;
use std::{fmt, path::Path};

/// This is the first step towards having custom errors
pub const GIT_REQUEST_NOT_FOUND: &str = "Git object doesn't exist";

/// Represents a git repository within an oll library. includes helpers for
/// for interacting with the Git Repo.
/// Expects a path to the library, as well as the repo's namespace and name.
pub struct Repo {
    /// Path to the library
    lib_path: String,
    /// Repo namespace
    namespace: String,
    /// Repo name
    name: String,
    /// git2 repository pointing to the repo in the library.
    repo: Repository,
}

impl fmt::Debug for Repo {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(
            f,
            "Repo for {}/{} in the library at {}",
            self.namespace, self.name, self.lib_path
        )
    }
}

impl Repo {
    /// Create a new Repo object with helpers for interacting with a Git Repo.
    /// Expects a path to the library, as well as the repo's namespace and name.
    ///
    /// # Errors
    ///
    /// Will return `Err` if git repository does not exist at `{namespace}/{name}`
    /// in library, or if there is something wrong with the git repository.
    pub fn new(lib_path: &Path, namespace: &str, name: &str) -> anyhow::Result<Self> {
        let lib_path_str = lib_path.to_string_lossy();
        let repo_path = format!("{lib_path_str}/{namespace}/{name}");
        Ok(Self {
            lib_path: lib_path_str.into(),
            namespace: namespace.into(),
            name: name.into(),
            repo: Repository::open(repo_path)?,
        })
    }

    /// Returns bytes of blob found in the commit `commitish` at path `path`
    /// if a blob is not found at path, it will try adding ".html", "index.html,
    /// and "/index.html".
    /// Example usage:
    ///
    //// let content: Vec<u8> = repo.get_bytes_at_path(
    ////    "0f2f1ef9fa213dcf83e269bc832ab63435cbd4b1",
    ////    "us/ca/cities/san-mateo"
    //// );
    ///
    /// # Errors
    ///
    /// Will return `Err` if `commitish` does not exist in repo, if a blob does
    /// not exist in commit at `path`, or if there is a problem with reading repo.
    pub fn get_bytes_at_path(&self, commitish: &str, path: &str) -> anyhow::Result<Vec<u8>> {
        let base_revision = format!("{commitish}:{path}");
        for postfix in ["", "/index.html", ".html", "index.html"] {
            let query = &format!("{base_revision}{postfix}");
            let blob = self.find(query);
            if blob.is_ok() {
                tracing::trace!(query, "Found Git object");
                return blob;
            }
        }
        tracing::debug!(base_revision, "Couldn't find requeted Git object");
        anyhow::bail!(GIT_REQUEST_NOT_FOUND)
    }

    /// Find something like `abc123:/path/to/something.txt` in the Git repo
    fn find(&self, query: &str) -> anyhow::Result<Vec<u8>> {
        tracing::trace!(query, "Git reverse parse search");
        let obj = self.repo.revparse_single(query)?;
        let blob = obj.as_blob().context("Couldn't cast Git object to blob")?;
        Ok(blob.content().to_owned())
    }
}