Merge 143b24c6a5 into f3448f49f1

Enables applications to read piped data while maintaining interactive
keyboard input by redirecting stdin to /dev/tty when explicitly enabled.

README.md

@@ -378,6 +378,22 @@ Several games using the FTXUI have been made during the Game Jam:
 - [smoothlife](https://github.com/cpp-best-practices/game_jam/blob/main/Jam1_April_2022/smoothlife.md)
 - [Consu](https://github.com/cpp-best-practices/game_jam/blob/main/Jam1_April_2022/consu.md)
 
+## Advanced Usage
+
+### Piped Input Support
+
+If your application reads from stdin (piped data) and also needs interactive keyboard input:
+
+```cpp
+auto screen = ScreenInteractive::Fullscreen();
+screen.HandlePipedInput(true);  // Enable before Loop()
+screen.Loop(component);
+```
+
+This allows commands like `cat data.txt | your_app` to work with full keyboard interaction.
+
+**Note:** This feature is only available on POSIX systems (Linux/macOS). On Windows, the method call is a no-op.
+
 ## Build using CMake
 
 It is **highly** recommended to use CMake FetchContent to depend on FTXUI so you may specify which commit you would like to depend on.

examples/index.css

@@ -1,15 +1,19 @@
 @import url(https://fonts.googleapis.com/css?family=Khula:700);
 
+html {
+  --toc-width: 250px;
+}
+
 body {
-  background-color:#EEE;
+  background-color: #EEE;
-  padding:0px;
+  padding: 0px;
-  margin:0px;
+  margin: 0px;
   font-family: Khula, Helvetica, sans-serif;
   font-size: 130%;
 }
 
 .page {
-  max-width:1300px;
+  max-width: 1300px;
   margin: auto;
   padding: 10px;
 }
@@ -20,7 +24,7 @@ a {
   margin: 0 -.25rem;
   padding: 0 .25rem;
   transition: color .3s ease-in-out,
-              box-shadow .3s ease-in-out;
+    box-shadow .3s ease-in-out;
 }
 
 a:hover {
@@ -30,45 +34,48 @@ a:hover {
 
 h1 {
   text-decoration: underline;
-  width:100%;
+  width: 100%;
-  background-color: rgba(100,100,255,0.5);
+  background-color: rgba(100, 100, 255, 0.5);
   padding: 10px;
   margin: 0;
 }
 
 
 #selectExample {
-  flex:1;
+  flex: 1;
 }
 
-#selectExample, #selectExample option {
+#selectExample,
+#selectExample option {
   font-size: 16px;
   font-family: sans-serif;
   font-weight: 700;
   line-height: 1.3;
-  border:0px;
+  border: 0px;
   background-color: #bbb;
-  color:black;
+  color: black;
 }
 
 #selectExample:focus {
-  outline:none;
+  outline: none;
 }
 
 #terminal {
-  width:100%;
+  width: 100%;
   height 500px;
   height: calc(clamp(200px, 100vh - 300px, 900px));
   overflow: hidden;
-  border:none;
+  border: none;
-  background-color:black;
+  padding: 10px;
+  margin: 10px;
 }
 
 #terminalContainer {
   overflow: hidden;
   border-radius: 10px;
-  box-shadow: 0px 2px 10px 0px rgba(0,0,0,0.75),
+  box-shadow: 0px 2px 10px 0px rgba(0, 0, 0, 0.75),
-  0px 2px 80px 0px rgba(0,0,0,0.50);
+    0px 2px 80px 0px rgba(0, 0, 0, 0.50);
+  background-color: black;
 }
 
 .fakeButtons {
@@ -76,7 +83,7 @@ h1 {
   width: 10px;
   border-radius: 50%;
   border: 1px solid #000;
-  margin:6px;
+  margin: 6px;
   background-color: #ff3b47;
   border-color: #9d252b;
   display: inline-block;
@@ -95,13 +102,79 @@ h1 {
 }
 
 .fakeMenu {
-  display:flex;
+  display: flex;
   flex-direction: row;
-  width:100%;
+  width: 100%;
   box-sizing: border-box;
   height: 25px;
   background-color: #bbb;
-  color:black;
+  color: black;
   margin: 0 auto;
   overflow: hidden;
 }
+
+.toc-container {
+  position: fixed;
+  left: 0;
+  top: 0;
+  bottom: 0;
+  width: var(--toc-width);
+  background: white;
+  padding: 0;
+  overflow-y: auto;
+  overflow-x: hidden;
+  scrollbar-width: thin;
+}
+
+.toc-title {
+  font-weight: bold;
+  margin-bottom: 5px;
+  font-size: 0.9em;
+  color: #555;
+
+  position: sticky;
+  transition: position 1.0s ease-in-out;
+  top: 0;
+  z-index: 1;
+  padding: 20px;
+  margin: 0;
+
+  border-bottom: 1px solid #ddd;
+
+  /* Gradient background for the title */
+  background-color: #f0f0f0;
+}
+
+.toc-item {
+  padding: 3px 8px;
+  margin: 0;
+  cursor: pointer;
+  font-size: 0.85em;
+  border-radius: 3px;
+  transition: background 0.2s;
+}
+
+.toc-item:hover {
+  background: #f0f0f0;
+}
+
+.toc-item.selected {
+  background: #e0e0e0;
+  font-weight: bold;
+}
+
+@media (max-width: 1024px) {
+  .toc-container {
+    display: none;
+  }
+
+  .page {
+    margin-left: 0;
+  }
+}
+
+@media (min-width: 1025px) {
+  .page {
+    margin-left: calc(var(--toc-width) + 20px);
+  }
+}

examples/index.html

@@ -9,13 +9,18 @@
     <script type="module" src="index.mjs"></script>
   </head>
   <body>
+    <div class="toc-container">
+      <div class="toc-list"></div>
+    </div>
     <script id="example_script"></script>
 
     <div class="page">
       <p>
         <a href="https://github.com/ArthurSonzogni/FTXUI">FTXUI</a> is a simple
         functional C++ library for terminal user interface. <br/>
-        This showcases the: <a href="https://github.com/ArthurSonzogni/FTXUI/tree/master/examples">./example/</a> folder. <br/>
+        This showcases the: <a
+          href="https://github.com/ArthurSonzogni/FTXUI/tree/master/examples">./example/</a>
+        folder. See <a id="source">source</a>.
       </p>
 
       <div id="terminalContainer">

examples/index.mjs

@@ -92,6 +92,69 @@ window.Module = {
   },
 };
 
+const source = document.querySelector("#source");
+source.href = "https://github.com/ArthurSonzogni/FTXUI/blob/main/examples/" + example + ".cpp";
+
 const words = example.split('/')
 words[1] = "ftxui_example_" + words[1] + ".js"
 document.querySelector("#example_script").src = words.join('/');
+
+
+// Table of Contents (TOC) for quick navigation.
+
+// Get select element
+const selectEl = document.querySelector('select#selectExample');
+if (!selectEl) {
+  console.error('select#selectExample not found');
+} else {
+  // Get TOC container
+  const tocContainer = document.querySelector('.toc-container');
+  const tocList = tocContainer.querySelector('.toc-list');
+
+  // Group options by directory
+  const groupedOptions = Array.from(selectEl.options).reduce((acc, option) => {
+    const [dir, file] = option.text.split('/');
+    if (!acc[dir]) {
+      acc[dir] = [];
+    }
+    acc[dir].push({ option, file });
+    return acc;
+  }, {});
+
+  // Generate TOC items
+  for (const dir in groupedOptions) {
+    const dirContainer = document.createElement('div');
+
+    const dirHeader = document.createElement('div');
+    dirHeader.textContent = dir;
+    dirHeader.className = 'toc-title';
+    dirContainer.appendChild(dirHeader);
+
+    groupedOptions[dir].forEach(({ option, file }) => {
+      const tocItem = document.createElement('div');
+      tocItem.textContent = file;
+      tocItem.className = 'toc-item';
+
+      if (selectEl.options[selectEl.selectedIndex].value === option.value) {
+        tocItem.classList.add('selected');
+      }
+
+      // Click handler
+      tocItem.addEventListener('click', () => {
+        for(let i=0; i<selectEl.options.length; ++i) {
+          if (selectEl.options[i].value == option.value) {
+            selectEl.selectedIndex = i;
+            break;
+          }
+        }
+
+        history.pushState({}, "", "?file=" + option.value);
+        location.reload();
+      });
+
+      dirContainer.appendChild(tocItem);
+    });
+
+    tocList.appendChild(dirContainer);
+  }
+}''

include/ftxui/component/screen_interactive.hpp

@@ -47,6 +47,7 @@ class ScreenInteractive : public Screen {
 
   // Options. Must be called before Loop().
   void TrackMouse(bool enable = true);
+  void HandlePipedInput(bool enable = true);
 
   // Return the currently active screen, nullptr if none.
   static ScreenInteractive* Active();
@@ -141,6 +142,13 @@ class ScreenInteractive : public Screen {
   bool force_handle_ctrl_c_ = true;
   bool force_handle_ctrl_z_ = true;
 
+#if !defined(_WIN32) && !defined(__EMSCRIPTEN__)
+  // Piped input handling state (POSIX only)
+  bool handle_piped_input_ = false;
+  bool stdin_was_redirected_ = false;
+  int original_stdin_fd_ = -1;
+#endif
+
   // The style of the cursor to restore on exit.
   int cursor_reset_shape_ = 1;
 

src/ftxui/component/screen_interactive.cpp

@@ -372,6 +372,24 @@ void ScreenInteractive::TrackMouse(bool enable) {
   track_mouse_ = enable;
 }
 
+/// @brief Enable or disable automatic piped input handling.
+/// When enabled, FTXUI will detect piped input and redirect stdin to /dev/tty
+/// for keyboard input, allowing applications to read piped data while still
+/// receiving interactive keyboard events.
+/// @param enable Whether to enable piped input handling
+/// @note This must be called before Loop().
+/// @note This feature is disabled by default for backward compatibility.
+/// @note This feature is only available on POSIX systems (Linux/macOS).
+#if !defined(_WIN32) && !defined(__EMSCRIPTEN__)
+void ScreenInteractive::HandlePipedInput(bool enable) {
+  handle_piped_input_ = enable;
+}
+#else
+void ScreenInteractive::HandlePipedInput(bool /*enable*/) {
+  // This feature is not supported on this platform.
+}
+#endif
+
 /// @brief Add a task to the main loop.
 /// It will be executed later, after every other scheduled tasks.
 void ScreenInteractive::Post(Task task) {
@@ -658,6 +676,28 @@ void ScreenInteractive::Install() {
   // ensure it is fully applied:
   Flush();
 
+#if !defined(_WIN32) && !defined(__EMSCRIPTEN__)
+  // Handle piped input redirection if explicitly enabled by the application.
+  // This allows applications to read data from stdin while still receiving
+  // keyboard input from the terminal for interactive use.
+  if (handle_piped_input_ && !stdin_was_redirected_ && !isatty(STDIN_FILENO)) {
+    // Save the current stdin so we can restore it later
+    original_stdin_fd_ = dup(STDIN_FILENO);
+    if (original_stdin_fd_ >= 0) {
+      // Redirect stdin to the controlling terminal for keyboard input
+      if (freopen("/dev/tty", "r", stdin) != nullptr) {
+        stdin_was_redirected_ = true;
+      } else {
+        // Failed to open /dev/tty (containers, headless systems, etc.)
+        // Clean up and continue without redirection
+        close(original_stdin_fd_);
+        original_stdin_fd_ = -1;
+      }
+    }
+    // If dup() failed, we silently continue without redirection
+  }
+#endif
+
   quit_ = false;
 
   PostAnimationTask();
@@ -666,6 +706,17 @@ void ScreenInteractive::Install() {
 // private
 void ScreenInteractive::Uninstall() {
   ExitNow();
+  
+#if !defined(_WIN32) && !defined(__EMSCRIPTEN__)
+  // Restore stdin to its original state if we redirected it
+  if (stdin_was_redirected_ && original_stdin_fd_ >= 0) {
+    dup2(original_stdin_fd_, STDIN_FILENO);
+    close(original_stdin_fd_);
+    original_stdin_fd_ = -1;
+    stdin_was_redirected_ = false;
+  }
+#endif
+  
   OnExit();
 }
 

src/ftxui/component/screen_interactive_piped_input_test.cpp

@@ -0,0 +1,219 @@
+// Copyright 2025 Arthur Sonzogni. All rights reserved.
+// Use of this source code is governed by the MIT license that can be found in
+// the LICENSE file.
+#include <gtest/gtest.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <cstdio>
+#include <sys/stat.h>
+
+#include "ftxui/component/component.hpp"
+#include "ftxui/component/screen_interactive.hpp"
+#include "ftxui/dom/elements.hpp"
+
+#if !defined(_WIN32) && !defined(__EMSCRIPTEN__)
+
+namespace ftxui {
+
+namespace {
+
+// Test fixture for piped input functionality
+class PipedInputTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    // Save original stdin for restoration
+    original_stdin_ = dup(STDIN_FILENO);
+  }
+
+  void TearDown() override {
+    // Restore original stdin
+    if (original_stdin_ >= 0) {
+      dup2(original_stdin_, STDIN_FILENO);
+      close(original_stdin_);
+    }
+  }
+
+  // Create a pipe and redirect stdin to read from it
+  void SetupPipedStdin() {
+    if (pipe(pipe_fds_) == 0) {
+      dup2(pipe_fds_[0], STDIN_FILENO);
+      close(pipe_fds_[0]);
+      // Keep write end open for writing test data
+      piped_stdin_setup_ = true;
+    }
+  }
+
+  // Write test data to the piped stdin
+  void WriteToPipedStdin(const std::string& data) {
+    if (piped_stdin_setup_) {
+      write(pipe_fds_[1], data.c_str(), data.length());
+      close(pipe_fds_[1]); // Close write end to signal EOF
+    }
+  }
+
+  // Check if /dev/tty is available (not available in some CI environments)
+  bool IsTtyAvailable() {
+    struct stat st;
+    return stat("/dev/tty", &st) == 0;
+  }
+
+ private:
+  int original_stdin_ = -1;
+  int pipe_fds_[2] = {-1, -1};
+  bool piped_stdin_setup_ = false;
+};
+
+TEST_F(PipedInputTest, DefaultBehaviorNoChange) {
+  // Test that HandlePipedInput is disabled by default
+  auto screen = ScreenInteractive::TerminalOutput();
+  auto component = Renderer([] { return text("test"); });
+
+  SetupPipedStdin();
+  WriteToPipedStdin("test data\n");
+
+  // Install should not redirect stdin since HandlePipedInput not called
+  screen.Install();
+  
+  // Stdin should still be the pipe (isatty should return false)
+  EXPECT_FALSE(isatty(STDIN_FILENO));
+  
+  screen.Uninstall();
+}
+
+TEST_F(PipedInputTest, ExplicitlyDisabled) {
+  // Test that explicitly disabling works
+  auto screen = ScreenInteractive::TerminalOutput();
+  screen.HandlePipedInput(false);
+  auto component = Renderer([] { return text("test"); });
+
+  SetupPipedStdin();
+  WriteToPipedStdin("test data\n");
+
+  screen.Install();
+  
+  // Stdin should still be the pipe since feature is disabled
+  EXPECT_FALSE(isatty(STDIN_FILENO));
+  
+  screen.Uninstall();
+}
+
+TEST_F(PipedInputTest, PipedInputDetectionAndRedirection) {
+  if (!IsTtyAvailable()) {
+    GTEST_SKIP() << "/dev/tty not available in this environment";
+  }
+
+  auto screen = ScreenInteractive::TerminalOutput();
+  screen.HandlePipedInput(true); // Explicitly enable
+  auto component = Renderer([] { return text("test"); });
+
+  SetupPipedStdin();
+  WriteToPipedStdin("test data\n");
+
+  // Before install: stdin should be piped
+  EXPECT_FALSE(isatty(STDIN_FILENO));
+
+  screen.Install();
+  
+  // After install with piped input handling: stdin should be redirected to tty
+  EXPECT_TRUE(isatty(STDIN_FILENO));
+  
+  screen.Uninstall();
+  
+  // After uninstall: stdin should be restored to original state
+  // Note: This will be the pipe we set up, so it should be non-tty
+  EXPECT_FALSE(isatty(STDIN_FILENO));
+}
+
+TEST_F(PipedInputTest, NormalStdinUnchanged) {
+  // Test that normal stdin (not piped) is not affected
+  auto screen = ScreenInteractive::TerminalOutput();
+  screen.HandlePipedInput(true);
+  auto component = Renderer([] { return text("test"); });
+
+  // Don't setup piped stdin - use normal stdin
+  bool original_isatty = isatty(STDIN_FILENO);
+
+  screen.Install();
+  
+  // Stdin should remain unchanged
+  EXPECT_EQ(original_isatty, isatty(STDIN_FILENO));
+  
+  screen.Uninstall();
+  
+  // Stdin should still be unchanged
+  EXPECT_EQ(original_isatty, isatty(STDIN_FILENO));
+}
+
+TEST_F(PipedInputTest, MultipleInstallUninstallCycles) {
+  if (!IsTtyAvailable()) {
+    GTEST_SKIP() << "/dev/tty not available in this environment";
+  }
+
+  auto screen = ScreenInteractive::TerminalOutput();
+  screen.HandlePipedInput(true);
+  auto component = Renderer([] { return text("test"); });
+
+  SetupPipedStdin();
+  WriteToPipedStdin("test data\n");
+
+  // First cycle
+  screen.Install();
+  EXPECT_TRUE(isatty(STDIN_FILENO));
+  screen.Uninstall();
+  EXPECT_FALSE(isatty(STDIN_FILENO));
+
+  // Second cycle should work the same
+  screen.Install();
+  EXPECT_TRUE(isatty(STDIN_FILENO));
+  screen.Uninstall();
+  EXPECT_FALSE(isatty(STDIN_FILENO));
+}
+
+TEST_F(PipedInputTest, HandlePipedInputMethodBehavior) {
+  auto screen = ScreenInteractive::TerminalOutput();
+  
+  // Test method can be called multiple times
+  screen.HandlePipedInput(true);
+  screen.HandlePipedInput(false);
+  screen.HandlePipedInput(true);
+  
+  // Should be enabled after last call
+  SetupPipedStdin();
+  WriteToPipedStdin("test data\n");
+
+  if (IsTtyAvailable()) {
+    screen.Install();
+    EXPECT_TRUE(isatty(STDIN_FILENO));
+    screen.Uninstall();
+  }
+}
+
+// Test the graceful fallback when /dev/tty is not available
+// This test simulates environments like containers where /dev/tty might not exist
+TEST_F(PipedInputTest, GracefulFallbackWhenTtyUnavailable) {
+  auto screen = ScreenInteractive::TerminalOutput();
+  screen.HandlePipedInput(true);
+  auto component = Renderer([] { return text("test"); });
+
+  SetupPipedStdin();
+  WriteToPipedStdin("test data\n");
+
+  // This test doesn't directly mock /dev/tty unavailability since that's hard to do
+  // in a unit test environment, but the code path handles freopen() failure gracefully
+  screen.Install();
+  
+  // The behavior depends on whether /dev/tty is available
+  // If available, stdin gets redirected; if not, it remains piped
+  // Both behaviors are correct
+  
+  screen.Uninstall();
+  
+  // After uninstall, stdin should be restored
+  EXPECT_FALSE(isatty(STDIN_FILENO)); // Should still be our test pipe
+}
+
+}  // namespace
+
+}  // namespace ftxui
+
+#endif  // !defined(_WIN32) && !defined(__EMSCRIPTEN__)