Checkout subcommand (#21)

* commit_wrapper now built from reposiroty_wrapper

* Replaced std::string with std::string_view

* Annotated commit wrapper

* Minimal implementation of checkout subcommand

Author: JohanMabille

CMakeLists.txt

@@ -43,6 +43,8 @@ set(GIT2CPP_SRC
     ${GIT2CPP_SOURCE_DIR}/subcommand/add_subcommand.hpp
     ${GIT2CPP_SOURCE_DIR}/subcommand/branch_subcommand.cpp
     ${GIT2CPP_SOURCE_DIR}/subcommand/branch_subcommand.hpp
+    ${GIT2CPP_SOURCE_DIR}/subcommand/checkout_subcommand.cpp
+    ${GIT2CPP_SOURCE_DIR}/subcommand/checkout_subcommand.hpp
     ${GIT2CPP_SOURCE_DIR}/subcommand/init_subcommand.cpp
     ${GIT2CPP_SOURCE_DIR}/subcommand/init_subcommand.hpp
     ${GIT2CPP_SOURCE_DIR}/subcommand/status_subcommand.cpp
@@ -51,12 +53,16 @@ set(GIT2CPP_SRC
     ${GIT2CPP_SOURCE_DIR}/utils/common.hpp
     ${GIT2CPP_SOURCE_DIR}/utils/git_exception.cpp
     ${GIT2CPP_SOURCE_DIR}/utils/git_exception.hpp
+    ${GIT2CPP_SOURCE_DIR}/wrapper/annotated_commit_wrapper.cpp
+    ${GIT2CPP_SOURCE_DIR}/wrapper/annotated_commit_wrapper.hpp
     ${GIT2CPP_SOURCE_DIR}/wrapper/branch_wrapper.cpp
     ${GIT2CPP_SOURCE_DIR}/wrapper/branch_wrapper.hpp
     ${GIT2CPP_SOURCE_DIR}/wrapper/commit_wrapper.cpp
     ${GIT2CPP_SOURCE_DIR}/wrapper/commit_wrapper.hpp
     ${GIT2CPP_SOURCE_DIR}/wrapper/index_wrapper.cpp
     ${GIT2CPP_SOURCE_DIR}/wrapper/index_wrapper.hpp
+    ${GIT2CPP_SOURCE_DIR}/wrapper/object_wrapper.cpp
+    ${GIT2CPP_SOURCE_DIR}/wrapper/object_wrapper.hpp
     ${GIT2CPP_SOURCE_DIR}/wrapper/refs_wrapper.cpp
     ${GIT2CPP_SOURCE_DIR}/wrapper/refs_wrapper.hpp
     ${GIT2CPP_SOURCE_DIR}/wrapper/repository_wrapper.cpp

src/main.cpp

@@ -6,6 +6,7 @@
 #include "version.hpp"
 #include "subcommand/add_subcommand.hpp"
 #include "subcommand/branch_subcommand.hpp"
+#include "subcommand/checkout_subcommand.hpp"
 #include "subcommand/init_subcommand.hpp"
 #include "subcommand/status_subcommand.hpp"
 
@@ -25,6 +26,7 @@ int main(int argc, char** argv)
         status_subcommand status(lg2_obj, app);
         add_subcommand add(lg2_obj, app);
         branch_subcommand(lg2_obj, app);
+        checkout_subcommand(lg2_obj, app);
 
         app.parse(argc, argv);
 

src/subcommand/checkout_subcommand.cpp

@@ -0,0 +1,127 @@
+#include <iostream>
+#include <sstream>
+
+#include "../subcommand/checkout_subcommand.hpp"
+#include "../utils/git_exception.hpp"
+#include "../wrapper/repository_wrapper.hpp"
+
+checkout_subcommand::checkout_subcommand(const libgit2_object&, CLI::App& app)
+{
+    auto* sub = app.add_subcommand("checkout", "Switch branches or restore working tree files");
+
+    sub->add_option("<branch>", m_branch_name, "Branch to checkout");
+    sub->add_flag("-b", m_create_flag, "Create a new branch before checking it out");
+    sub->add_flag("-B", m_force_create_flag, "Create a new branch or reset it if it exists before checking it out");
+    sub->add_flag("-f, --force", m_force_checkout_flag, "When switching branches, proceed even if the index or the working tree differs from HEAD, and even if there are untracked files in the way");
+
+    sub->callback([this]() { this->run(); });
+}
+
+void checkout_subcommand::run()
+{
+    auto directory = get_current_git_path();
+    auto repo = repository_wrapper::open(directory);
+
+    if (repo.state() != GIT_REPOSITORY_STATE_NONE)
+    {
+        throw std::runtime_error("Cannot checkout, repository is in unexpected state");
+    }
+
+    git_checkout_options options;
+    git_checkout_options_init(&options, GIT_CHECKOUT_OPTIONS_VERSION);
+
+    if(m_force_checkout_flag)
+    {
+        options.checkout_strategy = GIT_CHECKOUT_FORCE;
+    }
+
+    if (m_create_flag || m_force_create_flag)
+    {
+        auto annotated_commit = create_local_branch(repo, m_branch_name, m_force_create_flag);
+        checkout_tree(repo, annotated_commit, m_branch_name, options);
+        update_head(repo, annotated_commit, m_branch_name);
+    }
+    else
+    {
+        auto optional_commit = resolve_local_ref(repo, m_branch_name);
+        if (!optional_commit)
+        {
+            // TODO: handle remote refs
+            std::ostringstream buffer;
+            buffer << "error: could not resolve pathspec '" << m_branch_name << "'" << std::endl;
+            throw std::runtime_error(buffer.str());
+        }
+        checkout_tree(repo, *optional_commit, m_branch_name, options);
+        update_head(repo, *optional_commit, m_branch_name);
+    }
+}
+
+std::optional<annotated_commit_wrapper> checkout_subcommand::resolve_local_ref
+(
+    const repository_wrapper& repo,
+    const std::string& target_name
+)
+{
+    if (auto ref = repo.find_reference_dwim(target_name))
+    {
+        return repo.find_annotated_commit(*ref);
+    }
+    else if (auto obj = repo.revparse_single(target_name))
+    {
+        return repo.find_annotated_commit(obj->oid());
+    }
+    else
+    {
+        return std::nullopt;
+    }
+}
+
+annotated_commit_wrapper checkout_subcommand::create_local_branch
+(
+    repository_wrapper& repo,
+    const std::string& target_name,
+    bool force
+)
+{
+    auto branch = repo.create_branch(target_name, force);
+    return repo.find_annotated_commit(branch);
+}
+
+void checkout_subcommand::checkout_tree
+(
+    const repository_wrapper& repo,
+    const annotated_commit_wrapper& target_annotated_commit,
+    const std::string& target_name,
+    const git_checkout_options& options
+)
+{
+    auto target_commit = repo.find_commit(target_annotated_commit.oid());
+    throwIfError(git_checkout_tree(repo, target_commit, &options));
+}
+
+void checkout_subcommand::update_head
+(
+    repository_wrapper& repo,
+    const annotated_commit_wrapper& target_annotated_commit,
+    const std::string& target_name
+)
+{
+    std::string_view annotated_ref = target_annotated_commit.reference_name();
+    if (!annotated_ref.empty())
+    {
+        auto ref = repo.find_reference(annotated_ref);
+        if (ref.is_remote())
+        {
+            auto branch = repo.create_branch(target_name, target_annotated_commit);
+            repo.set_head(branch.reference_name());
+        }
+        else
+        {
+            repo.set_head(annotated_ref);
+        }
+    }
+    else
+    {
+        repo.set_head_detached(target_annotated_commit);
+    }
+}

src/subcommand/checkout_subcommand.hpp

@@ -0,0 +1,52 @@
+#pragma once
+
+#include <optional>
+#include <string>
+
+#include <CLI/CLI.hpp>
+
+#include "../utils/common.hpp"
+#include "../wrapper/repository_wrapper.hpp"
+
+class checkout_subcommand
+{
+public:
+
+    explicit checkout_subcommand(const libgit2_object&, CLI::App& app);
+    void run();
+
+private:
+
+    std::optional<annotated_commit_wrapper> resolve_local_ref
+    (
+        const repository_wrapper& repo,
+        const std::string& target_name
+    );
+
+    annotated_commit_wrapper create_local_branch
+    (
+        repository_wrapper& repo,
+        const std::string& target_name,
+        bool force
+    );
+
+    void checkout_tree
+    (
+        const repository_wrapper& repo,
+        const annotated_commit_wrapper& target_annotated_commit,
+        const std::string& target_name,
+        const git_checkout_options& options
+    );
+
+    void update_head
+    (
+        repository_wrapper& repo,
+        const annotated_commit_wrapper& target_annotated_commit,
+        const std::string& target_name
+    );
+
+    std::string m_branch_name = {};
+    bool m_create_flag = false;
+    bool m_force_create_flag = false;
+    bool m_force_checkout_flag = false;
+};

src/wrapper/annotated_commit_wrapper.cpp

@@ -0,0 +1,23 @@
+#include "../wrapper/annotated_commit_wrapper.hpp"
+
+annotated_commit_wrapper::annotated_commit_wrapper(git_annotated_commit* commit)
+    : base_type(commit)
+{
+}
+
+annotated_commit_wrapper::~annotated_commit_wrapper()
+{
+    git_annotated_commit_free(p_resource);
+    p_resource = nullptr;
+}
+
+const git_oid& annotated_commit_wrapper::oid() const
+{
+    return *git_annotated_commit_id(p_resource);
+}
+
+std::string_view annotated_commit_wrapper::reference_name() const
+{
+    const char* res = git_annotated_commit_ref(*this);
+    return res ? res : std::string_view{};
+}

src/wrapper/annotated_commit_wrapper.hpp

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <string_view>
+
+#include <git2.h>
+
+#include "../wrapper/wrapper_base.hpp"
+
+class annotated_commit_wrapper : public wrapper_base<git_annotated_commit>
+{
+public:
+
+    using base_type = wrapper_base<git_annotated_commit>;
+
+    ~annotated_commit_wrapper();
+
+    annotated_commit_wrapper(annotated_commit_wrapper&&) noexcept = default;
+    annotated_commit_wrapper& operator=(annotated_commit_wrapper&&) noexcept = default;
+
+    const git_oid& oid() const;
+    std::string_view reference_name() const;
+
+private:
+
+    annotated_commit_wrapper(git_annotated_commit* commit);
+
+    friend class repository_wrapper;
+};
+

src/wrapper/branch_wrapper.cpp

@@ -19,10 +19,16 @@ branch_wrapper::~branch_wrapper()
 std::string_view branch_wrapper::name() const
 {
     const char* out = nullptr;
-    throwIfError(git_branch_name(&out, p_resource));
+    throwIfError(git_branch_name(&out, *this));
     return std::string_view(out);
 }
 
+std::string_view branch_wrapper::reference_name() const
+{
+    const char* out = git_reference_name(*this);
+    return out ? out : std::string_view();
+}
+
 void delete_branch(branch_wrapper&& branch)
 {
     throwIfError(git_branch_delete(branch));

src/wrapper/branch_wrapper.hpp

@@ -21,6 +21,7 @@ class branch_wrapper : public wrapper_base<git_reference>
     branch_wrapper& operator=(branch_wrapper&&) = default;
 
     std::string_view name() const;
+    std::string_view reference_name() const;
 
 private:
 

src/wrapper/commit_wrapper.cpp

@@ -1,20 +1,23 @@
-#include "../utils/git_exception.hpp"
 #include "../wrapper/commit_wrapper.hpp"
-#include "../wrapper/repository_wrapper.hpp"
+
+commit_wrapper::commit_wrapper(git_commit* commit)
+    : base_type(commit)
+{
+}
 
 commit_wrapper::~commit_wrapper()
 {
     git_commit_free(p_resource);
     p_resource = nullptr;
 }
 
-
-commit_wrapper commit_wrapper::from_reference_name(const repository_wrapper& repo, const std::string& ref_name)
+commit_wrapper::operator git_object*() const noexcept
 {
-    git_oid oid_parent_commit;
-    throwIfError(git_reference_name_to_id(&oid_parent_commit, repo, ref_name.c_str()));
+    return reinterpret_cast<git_object*>(p_resource);
+}
 
-    commit_wrapper cw;
-    throwIfError(git_commit_lookup(&(cw.p_resource), repo, &oid_parent_commit));
-    return cw;
+const git_oid& commit_wrapper::oid() const
+{
+    return *git_commit_id(p_resource);
 }
+

src/wrapper/commit_wrapper.hpp

@@ -1,26 +1,27 @@
 #pragma once
 
-#include <string>
-
 #include <git2.h>
 
 #include "../wrapper/wrapper_base.hpp"
 
-class repository_wrapper;
-
 class commit_wrapper : public wrapper_base<git_commit>
 {
 public:
 
+    using base_type = wrapper_base<git_commit>;
+
     ~commit_wrapper();
 
     commit_wrapper(commit_wrapper&&) noexcept = default;
     commit_wrapper& operator=(commit_wrapper&&) noexcept = default;
 
-    static commit_wrapper
-    from_reference_name(const repository_wrapper& repo, const std::string& ref_name = "HEAD");
+    operator git_object*() const noexcept;
+
+    const git_oid& oid() const;
 
 private:
 
-    commit_wrapper() = default;
+    commit_wrapper(git_commit* commit);
+
+    friend class repository_wrapper;
 };