Intial version of git

Author: Asdts

.gitattributes

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+* text=auto

.gitignore

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+# Prerequisites
+*.d
+
+# Compiled Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Dynamic libraries
+*.so
+*.dylib
+*.dll
+
+# Fortran module files
+*.mod
+*.smod
+
+# Compiled Static libraries
+*.lai
+*.la
+*.a
+*.lib
+
+# Executables
+*.exe
+*.out
+*.app
+server
+
+# CMake
+CMakeLists.txt.user
+CMakeCache.txt
+CMakeFiles
+CMakeScripts
+Testing
+Makefile
+cmake_install.cmake
+install_manifest.txt
+compile_commands.json
+CTestTestfile.cmake
+_deps
+
+build/
+vcpkg_installed
+.vscode/

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.13)
+
+project(git-starter-cpp)
+
+set(CMAKE_CXX_STANDARD 23) # Enable the C++23 standard
+
+file(GLOB_RECURSE SOURCE_FILES src/*.cpp src/*.hpp)
+
+add_executable(git ${SOURCE_FILES})
+
+find_package(OpenSSL REQUIRED)
+target_link_libraries(git OpenSSL::SSL OpenSSL::Crypto)
+
+target_link_libraries(git -lz)

src/Server.cpp

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+#include <iostream>
+#include <filesystem>
+#include <fstream>
+#include <string>
+#include <zlib.h>
+#include <vector>
+#include <openssl/sha.h>
+
+
+using namespace std;
+
+#define fs filesystem
+
+
+string sha_file(string basicString);
+void compressFile(string basicString, uLong *pInt, unsigned char data[20]);
+void compressFile(const string data, uLong *bound, unsigned char *dest) ;
+void hash_object(string file);
+
+
+int main(int argc, char *argv[])
+{
+    // Flush after every cout / cerr
+    cout << unitbuf;
+    cerr << unitbuf;
+
+    // You can use print statements as follows for debugging, they'll be visible when running tests.
+    cerr << "Logs from your program will appear here!\n";
+
+    // Uncomment this block to pass the first stage
+    //
+    if (argc < 2) {
+        cerr << "No command provided.\n";
+        return EXIT_FAILURE;
+    }
+    
+    string command = argv[1];
+    // cout << "Command: " << command << '\n';
+    
+    if (command == "init") {
+        try {
+            fs::create_directory(".git");
+            fs::create_directory(".git/objects");
+            fs::create_directory(".git/refs");
+    
+            ofstream headFile(".git/HEAD");
+            if (headFile.is_open()) {
+                headFile << "ref: refs/heads/main\n";
+                headFile.close();
+            } else {
+                cerr << "Failed to create .git/HEAD file.\n";
+                return EXIT_FAILURE;
+            }
+    
+            cout << "Initialized git directory\n";
+        } catch (const fs::filesystem_error& e) {
+            cerr << e.what() << '\n';
+            return EXIT_FAILURE;
+        }
+    }else if (command == "cat--file" || command == "cat-file") {
+        if (argc < 4 || (string(argv[2]) != "-p")) {
+            cerr << "No object hash provided.\n";
+            cerr << "required `-p <blob_sha>`\n";
+            return EXIT_FAILURE;
+        }
+
+        const auto blobHash = string_view(argv[3],40);
+        const auto blobDir = blobHash.substr(0, 2);
+        const auto blobName = blobHash.substr(2);
+        const auto blobPath = fs::path(".git") / "objects" / blobDir / blobName;
+
+        auto input = ifstream(blobPath);
+
+        if(!input.is_open()){
+            cerr << "Failed to open" << blobPath << "file.\n";
+            return EXIT_FAILURE;
+        }
+
+        const auto blobData = string(istreambuf_iterator<char>(input), istreambuf_iterator<char>());
+        auto buf = string();
+        buf.resize(blobData.size());
+        while(true){
+            auto len = buf.size();
+            if(auto res = uncompress((uint8_t*)buf.data(), &len, (uint8_t*)blobData.data(), blobData.size()); res == Z_BUF_ERROR){
+                buf.resize(len*2);
+                break;
+                }
+            else if(res != Z_OK){
+                cerr << "Failed to decompress blob data.\n";
+                return EXIT_FAILURE;
+            }
+            else{
+                buf.resize(len);
+                break;
+            }
+        }
+        cout << string_view(buf).substr(buf.find('\0')+1)<<flush;
+    }else if (command == "hash--object" || command == "hash-object"){
+        if(argc < 4 || (string(argv[2]) != "-w")){
+            cerr << "No file provided.\n";
+            cerr << "required `-w <file>`\n";
+            return EXIT_FAILURE;
+        }
+
+        string hash = argv[3];
+        hash_object(hash);
+
+    }
+     else {
+        cerr << "Unknown command " << command << '\n';
+        return EXIT_FAILURE;
+    }
+    
+    return EXIT_SUCCESS;
+}
+
+
+
+void hash_object(string file) {
+    ifstream t(file);
+    stringstream data;
+    data << t.rdbuf();
+    string content = "blob " + to_string(data.str().length()) + '\0' + data.str();
+    // Calculate SHA1 hash
+    string buffer = sha_file(content);
+    // Compress blob content
+    uLong bound = compressBound(content.size());
+    unsigned char compressedData[bound];
+    compressFile(content, &bound, compressedData);
+    // Write compressed data to .git/objects
+    string dir = ".git/objects/" + buffer.substr(0,2);
+    fs::create_directory(dir);
+    string objectPath = dir + "/" + buffer.substr(2);
+    ofstream objectFile(objectPath, ios::binary);
+    objectFile.write((char *)compressedData, bound);
+    objectFile.close();
+}
+void compressFile(const string data, uLong *bound, unsigned char *dest) {
+    compress(dest, bound, (const Bytef *)data.c_str(), data.size());
+}
+string sha_file(string data) {
+    unsigned char hash[20];
+    SHA1((unsigned char *)data.c_str(), data.size(), hash);
+    stringstream ss;
+    ss << hex << setfill('0');
+    for (const auto& byte : hash) {
+        ss << setw(2) << static_cast<int>(byte);
+    }
+    cout << ss.str() << endl;
+    return ss.str();
+}

vcpkg-configuration.json

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+{
+    "default-registry": {
+        "kind": "git",
+        "baseline": "c4af3593e1f1aa9e14a560a09e45ea2cb0dfd74d",
+        "repository": "https://github.com/microsoft/vcpkg"
+    },
+    "registries": [
+        {
+            "kind": "artifact",
+            "location": "https://github.com/microsoft/vcpkg-ce-catalog/archive/refs/heads/main.zip",
+            "name": "microsoft"
+        }
+    ]
+}

vcpkg.json

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+{
+    "dependencies": []
+}

your_program.sh

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+#!/bin/sh
+
+
+set -e 
+(
+  cd "$(dirname "$0")"
+  cmake -B build -S . -DCMAKE_TOOLCHAIN_FILE=${VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake
+  cmake --build ./build
+)
+
+exec $(dirname "$0")/build/git "$@"