AdvC++ - adding files directory

AdvancedCppV2/Presentation/exercises/files/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.2)
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+project(Files)
+
+set(SRC_LIST
+    main.cpp
+)
+
+add_executable(${PROJECT_NAME} ${SRC_LIST})
+target_compile_options(${PROJECT_NAME} PUBLIC -Wall -Werror -Wpedantic -Wextra)
+target_include_directories(${PROJECT_NAME} PUBLIC ${CMAKE_SOURCE_DIR})

AdvancedCppV2/Presentation/exercises/files/README.md

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+## Linux compilation
+
+    > mkdir build
+    > cd build
+    > cmake -DCMAKE_BUILD_TYPE=Debug ..
+    > make
+
+## Exercise
+
+Open project `files`. Write a program which modify files under `project` directory:
+
+- Change permision for all .exe files to `rwxrw-rw-`.
+- Change permision for all .cpp and .hpp files to `rw-r--r--`.
+
+You should get output like this:
+
+```Bash
+File: "fileA.cpp"          | Permissions: rw-------
+File: "fileA.hpp"          | Permissions: rw-------
+File: "fileB.cpp"          | Permissions: rw-------
+File: "fileB.hpp"          | Permissions: rw-------
+File: "fileC.cpp"          | Permissions: rw-------
+File: "fileC.hpp"          | Permissions: rw-------
+File: "project.exe"        | Permissions: rw-------
+
+File: "fileA.cpp"          | Permissions: rw-r--r--
+File: "fileA.hpp"          | Permissions: rw-r--r--
+File: "fileB.cpp"          | Permissions: rw-r--r--
+File: "fileB.hpp"          | Permissions: rw-r--r--
+File: "fileC.cpp"          | Permissions: rw-r--r--
+File: "fileC.hpp"          | Permissions: rw-r--r--
+File: "project.exe"        | Permissions: rwxrw-rw-
+```

AdvancedCppV2/Presentation/exercises/files/main.cpp

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+#include <filesystem>
+#include <iostream>
+
+namespace fs = std::filesystem;
+
+void printPerms(fs::perms p) {
+    std::cout << ((p & fs::perms::owner_read) != fs::perms::none ? "r" : "-")
+              << ((p & fs::perms::owner_write) != fs::perms::none ? "w" : "-")
+              << ((p & fs::perms::owner_exec) != fs::perms::none ? "x" : "-")
+              << ((p & fs::perms::group_read) != fs::perms::none ? "r" : "-")
+              << ((p & fs::perms::group_write) != fs::perms::none ? "w" : "-")
+              << ((p & fs::perms::group_exec) != fs::perms::none ? "x" : "-")
+              << ((p & fs::perms::others_read) != fs::perms::none ? "r" : "-")
+              << ((p & fs::perms::others_write) != fs::perms::none ? "w" : "-")
+              << ((p & fs::perms::others_exec) != fs::perms::none ? "x" : "-")
+              << '\n';
+}
+
+void printPermissionsForDir() {
+    for (const auto& entry : fs::directory_iterator(fs::current_path().string() + "/project")) {
+        if (fs::is_regular_file(entry.path())) {
+            std::cout << "File: "
+                      << std::left << std::setw(20)
+                      << entry.path().filename()
+                      << " | Permissions: ";
+            printPerms(fs::status(entry.path()).permissions());
+        }
+    }
+    std::cout << std::string(80, '_') << "\n\n";
+}
+
+void changePermissions() {
+}
+
+int main() {
+    printPermissionsForDir();
+    changePermissions();
+    printPermissionsForDir();
+
+    // Part 2 unncoment later
+    /* 
+    auto print_last_write_time = [](std::filesystem::file_time_type const& ftime) {
+        std::time_t time = std::chrono::system_clock::to_time_t(
+            std::chrono::file_clock::to_sys(ftime));
+        std::cout << "File write time is " << std::asctime(std::localtime(&time));
+    };
+    std::cout << "Last modified file is: " << *last_modify << '\n';
+    print_last_write_time(std::filesystem::last_write_time(*last_modify));
+    std::cout << "files which were longest unmodified: \n";
+    // Print it here
+    */
+}

AdvancedCppV2/Presentation/exercises/files/project/fileA.cpp

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+Hello FileA

AdvancedCppV2/Presentation/exercises/files/project/fileA.hpp

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+Hello FileA

AdvancedCppV2/Presentation/exercises/files/project/fileB.cpp

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+Hello FileB

AdvancedCppV2/Presentation/exercises/files/project/fileB.hpp

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+Hello FileB

AdvancedCppV2/Presentation/exercises/files/project/fileC.cpp

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+Hello FileC

AdvancedCppV2/Presentation/exercises/files/project/fileC.hpp

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+Hello FileC

AdvancedCppV2/Presentation/exercises/files/solutions/main.cpp

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+#include <chrono>
+#include <filesystem>
+#include <iostream>
+
+namespace fs = std::filesystem;
+
+void printPerms(fs::perms p) {
+    std::cout << ((p & fs::perms::owner_read) != fs::perms::none ? "r" : "-")
+              << ((p & fs::perms::owner_write) != fs::perms::none ? "w" : "-")
+              << ((p & fs::perms::owner_exec) != fs::perms::none ? "x" : "-")
+              << ((p & fs::perms::group_read) != fs::perms::none ? "r" : "-")
+              << ((p & fs::perms::group_write) != fs::perms::none ? "w" : "-")
+              << ((p & fs::perms::group_exec) != fs::perms::none ? "x" : "-")
+              << ((p & fs::perms::others_read) != fs::perms::none ? "r" : "-")
+              << ((p & fs::perms::others_write) != fs::perms::none ? "w" : "-")
+              << ((p & fs::perms::others_exec) != fs::perms::none ? "x" : "-")
+              << '\n';
+}
+
+void printPermissionsForDir() {
+    for (const auto& entry : fs::directory_iterator(fs::current_path() / "../project")) {
+        if (fs::is_regular_file(entry.path())) {
+            std::cout << "File: "
+                      << std::left << std::setw(20)
+                      << entry.path().filename()
+                      << " | Permissions: ";
+            printPerms(fs::status(entry.path()).permissions());
+        }
+    }
+    std::cout << std::string(80, '_') << "\n\n";
+}
+
+void changePermissions() {
+    for (auto& entry : fs::directory_iterator(fs::current_path() / "../project")) {
+        if (!entry.is_regular_file()) {
+            continue;
+        }
+
+        if (entry.path().extension() == ".exe") {
+            fs::permissions(entry.path(), fs::perms::owner_all |
+                                              fs::perms::group_read |
+                                              fs::perms::group_write |
+                                              fs::perms::others_read |
+                                              fs::perms::others_write);
+        } else if (entry.path().extension() == ".cpp" || entry.path().extension() == ".hpp") {
+            fs::permissions(entry.path(), fs::perms::owner_read |
+                                              fs::perms::owner_write |
+                                              fs::perms::group_read |
+                                              fs::perms::others_read);
+        }
+    }
+}
+
+int main() {
+    printPermissionsForDir();
+    changePermissions();
+    printPermissionsForDir();
+}

AdvancedCppV2/Presentation/exercises/files/solutions/main2.cpp

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+#include <algorithm>
+#include <chrono>
+#include <filesystem>
+#include <iostream>
+#include <iterator>
+#include <set>
+
+namespace fs = std::filesystem;
+
+int main() {
+    // Answer 1
+    auto print_last_write_time = [](std::filesystem::file_time_type const& ftime) {
+        std::time_t time = std::chrono::system_clock::to_time_t(
+            std::chrono::file_clock::to_sys(ftime));
+        std::cout << "File write time is " << std::asctime(std::localtime(&time));
+    };
+
+    // Need to copy paths to vector, because directory_iterator is input type!
+    // directory_iterator is a LegacyInputIterator that iterates over the directory_entry
+    std::vector<fs::path> paths;
+    std::transform(fs::directory_iterator(fs::current_path().string() + "/project"),
+                   {},
+                   std::back_inserter(paths),
+                   [](const auto& entry) { return entry.path(); });
+
+    const auto last_modify = std::min_element(
+        cbegin(paths),
+        cend(paths),
+        [&](const auto& lhs, const auto& rhs) {
+            const auto lhs_time = std::filesystem::last_write_time(lhs);
+            const auto rhs_time = std::filesystem::last_write_time(rhs);
+            return lhs_time > rhs_time;
+        });
+
+    std::cout << "Last modified file is: " << *last_modify << '\n';
+    print_last_write_time(std::filesystem::last_write_time(*last_modify));
+
+    // Answer 2
+    auto time_compare = [](const fs::path& lhs, const fs::path& rhs) {
+        const auto lhs_time = std::filesystem::last_write_time(lhs);
+        const auto rhs_time = std::filesystem::last_write_time(rhs);
+        return lhs_time == rhs_time ? lhs < rhs : lhs_time < rhs_time;
+    };
+
+    std::set<fs::path, decltype(time_compare)> lastModifiedFiles(
+        fs::directory_iterator(fs::current_path() / "../project"),
+        {},
+        time_compare);
+
+    std::cout << "files which were longest unmodified: \n";
+    std::transform(std::cbegin(lastModifiedFiles),
+                   std::next(std::cbegin(lastModifiedFiles), 3),
+                   std::ostream_iterator<std::string>(std::cout),
+                   [](const auto& path) {
+                       std::stringstream ss;
+                       std::time_t time = std::chrono::system_clock::to_time_t(
+                           std::chrono::file_clock::to_sys(std::filesystem::last_write_time(path)));
+                       ss << "File: " << path << " | last modify time: " << std::asctime(std::localtime(&time));
+
+                       return ss.str();
+                   });
+}