HackStudio: Add basic Git integration

This adds a "Git" tab to Hackstudio.
Currently has support for staging and unstaging files.

DevTools/HackStudio/Git/GitRepo.cpp

@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "GitRepo.h"
+#include <LibCore/Command.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+namespace HackStudio {
+
+GitRepo::CreateResult GitRepo::try_to_create(const LexicalPath& repository_root)
+{
+    if (!git_is_installed()) {
+        return { CreateResult::Type::GitProgramNotFound, nullptr };
+    }
+    if (!git_repo_exists(repository_root)) {
+        return { CreateResult::Type::NoGitRepo, nullptr };
+    }
+
+    return { CreateResult::Type::Success, adopt(*new GitRepo(repository_root)) };
+}
+
+RefPtr<GitRepo> GitRepo::initialize_repository(const LexicalPath& repository_root)
+{
+    auto res = command_wrapper("init", repository_root);
+    if (res.is_null())
+        return {};
+
+    ASSERT(git_repo_exists(repository_root));
+    return adopt(*new GitRepo(repository_root));
+}
+
+Vector<LexicalPath> GitRepo::unstaged_files() const
+{
+    auto modified = modified_files();
+    auto untracked = untracked_files();
+    modified.append(move(untracked));
+    return modified;
+}
+
+Vector<LexicalPath> GitRepo::staged_files() const
+{
+    auto raw_result = command("diff --cached --name-only");
+    if (raw_result.is_null())
+        return {};
+    return parse_files_list(raw_result);
+}
+
+Vector<LexicalPath> GitRepo::modified_files() const
+{
+    auto raw_result = command("ls-files --modified --exclude-standard");
+    if (raw_result.is_null())
+        return {};
+    return parse_files_list(raw_result);
+}
+
+Vector<LexicalPath> GitRepo::untracked_files() const
+{
+    auto raw_result = command("ls-files --others --exclude-standard");
+    if (raw_result.is_null())
+        return {};
+    return parse_files_list(raw_result);
+}
+
+Vector<LexicalPath> GitRepo::parse_files_list(const String& raw_result)
+{
+    auto lines = raw_result.split('\n');
+    Vector<LexicalPath> files;
+    for (const auto& line : lines) {
+        files.empend(line);
+    }
+    return files;
+}
+
+String GitRepo::command(const String& git_command) const
+{
+    return command_wrapper(git_command, m_repository_root);
+}
+
+String GitRepo::command_wrapper(const String& git_command, const LexicalPath& chdir)
+{
+    return Core::command(String::format("git %s", git_command.characters()), chdir);
+}
+
+bool GitRepo::git_is_installed()
+{
+    return !command_wrapper("--help", LexicalPath("/")).is_null();
+}
+
+bool GitRepo::git_repo_exists(const LexicalPath& repo_root)
+{
+    return !command_wrapper("status", repo_root).is_null();
+}
+
+bool GitRepo::stage(const LexicalPath& file)
+{
+    auto cmd = String::format("add %s", file.string().characters());
+    auto res = command(cmd);
+    return !res.is_null();
+}
+
+bool GitRepo::unstage(const LexicalPath& file)
+{
+    auto cmd = String::format("reset HEAD -- %s", file.string().characters());
+    return !command(cmd).is_null();
+}
+
+}