reorganize crates to make 'gitoxide' the CLI, and 'gitoxide-core' the library

The latter at least doesn't have to pull in CLI stuff, and allows people
to more easily reuse all functionality of gitoxide.

Author: Byron

Diff for: Cargo.lock

@@ -14,8 +14,7 @@ test = false
 doctest = false
 
 [dependencies]
-git-repository = { version = "0.1.0", path = "git-repository" }
-git-odb = { version = "0.1.0", path = "git-odb", default-features = false, features = ["fast-sha1"] }
+gitoxide-core = { version = "0.1.0", path = "gitoxide-core" }
 anyhow = "1.0.31"
 structopt = "0.3.14"
 
@@ -28,6 +27,7 @@ incremental = false
 
 [workspace]
 members = [
+    "gitoxide-core",
     "git-object",
     "git-odb",
     "git-repository",

Diff for: Cargo.toml

@@ -1,23 +1,12 @@
 [![Rust](https://github.com/Byron/git-oxide/workflows/Rust/badge.svg)](https://github.com/Byron/git-oxide/actions)
 
 **gio** is a command-line interface (*CLI*) to access git repositories. It's written to optimize the
-user-experience, and perform as good or better than the native implementation.
+user-experience, and perform as good or better than the native implementation, and make git tooling more
+hackable.
 
-The CLI uses various libraries to implement
+The CLI uses various crates, please see _'Development Status'_ for details.
 
- * [ ] a git *repository* and *references* (see `git-core`)
- * [ ] encoding and decoding git objects (see `git-object`)
- * [ ] a git object database (see `git-odb` and
-   [examples](https://github.com/Byron/git-oxide/tree/master/lib/git-odb/examples))
- * [ ] a transport layer for push and pull (see `git-transport`)
-
- **This project is early in development and currently strictly for fun**
- 
- **Currently I am implementing whatever is needed to set a new record for solving
- [this
- problem](https://github.com/gitpython-developers/GitPython/issues/765#issuecomment-396072153)**
-
-## Tasks
+## Development Status
 
 * **git-repository**
   * [x] initialize
@@ -212,3 +201,8 @@ Thus one has to post-process the file by reducing its size by one using `truncat
 * **deflate2** _(MIT Licensed)_
   * We use various abstractions to implement decompression and compression directly on top of the rather low-level `miniz_oxide` crate
 
+## Fun facts
+
+* Originally I was really fascinated by [this problem](https://github.com/gitpython-developers/GitPython/issues/765#issuecomment-396072153)
+  and believe that with `gitoxide` it will be possible to provide the fastest implementation for that problem.
+

Diff for: README.md

@@ -0,0 +1,13 @@
+[package]
+name = "gitoxide-core"
+description = "The library implementating all capabilities of the gitoxide CLI"
+version = "0.1.0"
+authors = ["Sebastian Thiel <[email protected]>"]
+publish = false
+license = "MIT"
+edition = "2018"
+
+[dependencies]
+git-repository = { version = "0.1.0", path = "../git-repository" }
+git-odb = { version = "0.1.0", path = "../git-odb", default-features = false, features = ["fast-sha1"] }
+anyhow = "1.0.31"

Diff for: gitoxide-core/Cargo.toml

@@ -0,0 +1,13 @@
+use anyhow::{Context, Result};
+use std::{io, path::Path};
+
+pub fn init() -> Result<()> {
+    git_repository::init::repository().with_context(|| "Repository initialization failed")
+}
+
+pub fn verify_pack_or_pack_index(path: impl AsRef<Path>, mut out: impl io::Write) -> Result<()> {
+    let pack = git_odb::pack::File::at(path).with_context(|| "Could not open pack file")?;
+    pack.verify_checksum().with_context(|| "Failed")?;
+    writeln!(out, "OK")?;
+    Ok(())
+}

Diff for: gitoxide-core/src/lib.rs

@@ -1,6 +1,8 @@
 #![forbid(unsafe_code)]
 
-use anyhow::{Context, Result};
+use anyhow::Result;
+use gitoxide_core as core;
+use std::io::stdout;
 use structopt::StructOpt;
 
 mod options {
@@ -48,16 +50,10 @@ mod options {
 fn main() -> Result<()> {
     let args = options::Args::from_args();
     match args.cmd {
-        options::Subcommands::Init => {
-            git_repository::init::repository().with_context(|| "Repository initialization failed")
-        }
+        options::Subcommands::Init => core::init(),
         options::Subcommands::Plumbing(cmd) => match cmd {
             options::Plumbing::VerifyPack { path } => {
-                let pack =
-                    git_odb::pack::File::at(path).with_context(|| "Could not open pack file")?;
-                pack.verify_checksum().with_context(|| "Failed")?;
-                println!("OK");
-                Ok(())
+                core::verify_pack_or_pack_index(path, stdout())
             }
         },
     }?;