add option to remove (common) ansi escape codes from on_write

Author: lionkor

CMakeLists.txt

@@ -27,9 +27,7 @@ if (DEFINED COMMANDLINE_SHARED_LIBS)
     set(BUILD_SHARED_LIBS "${COMMANDLINE_SHARED_LIBS}")
 endif ()
 
-add_library(commandline
-        ${COMMANDLINE_LIBTYPE}
-        src/impls.h
+set(COMMANDLINE_SRCS src/impls.h
         src/windows_impl.cpp
         src/linux_impl.cpp
         src/backends/InteractiveBackend.cpp
@@ -39,17 +37,24 @@ add_library(commandline
         src/commandline.h
         src/commandline.cpp
         src/backends/BufferedBackend.cpp
-        src/backends/BufferedBackend.h)
+        src/backends/BufferedBackend.h
+        src/helper/ansi.h
+        src/helper/ansi.cpp)
+
+add_library(commandline
+        ${COMMANDLINE_LIBTYPE}
+        ${COMMANDLINE_SRCS})
 
 add_library(commandline::commandline ALIAS commandline)
 
+target_compile_definitions(commandline PRIVATE -DDOCTEST_CONFIG_DISABLE=1)
 target_link_libraries(commandline Threads::Threads)
 if (${COMMANDLINE_PLATFORM_WINDOWS})
     target_compile_definitions(commandline PRIVATE -DPLATFORM_WINDOWS=1)
 elseif (${COMMANDLINE_PLATFORM_LINUX})
     target_compile_definitions(commandline PRIVATE -DPLATFORM_LINUX=1)
 endif ()
-target_include_directories(commandline PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/src")
+target_include_directories(commandline PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/src" "${CMAKE_CURRENT_SOURCE_DIR}/tests")
 
 option(BUILD_EXAMPLES "Build example program" ON)
 
@@ -64,3 +69,14 @@ if (BUILD_EXAMPLES)
     set_property(DIRECTORY ${CMAKE_SOURCE_DIR} PROPERTY VS_STARTUP_PROJECT commandline_test)
 endif ()
 
+option(COMMANDLINE_TESTS "Build tests" ON)
+
+if (DEFINED COMMANDLINE_TESTS)
+    add_executable(commandline_tests tests/tests.cpp ${COMMANDLINE_SRCS})
+    target_include_directories(commandline_tests PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/src" "${CMAKE_CURRENT_SOURCE_DIR}/tests")
+    if (${COMMANDLINE_PLATFORM_WINDOWS})
+        target_compile_definitions(commandline_tests PRIVATE -DPLATFORM_WINDOWS=1)
+    elseif (${COMMANDLINE_PLATFORM_LINUX})
+        target_compile_definitions(commandline_tests PRIVATE -DPLATFORM_LINUX=1)
+    endif ()
+endif ()

src/commandline.cpp

@@ -2,6 +2,7 @@
 
 #include "backends/BufferedBackend.h"
 #include "backends/InteractiveBackend.h"
+#include "helper/ansi.h"
 #include "impls.h"
 
 #include <memory>
@@ -20,7 +21,11 @@ Commandline::Commandline(const std::string& prompt) {
     };
     m_backend->on_write = [this](const std::string& str) {
         if (on_write) {
-            on_write(str);
+            if (m_ansi_escape_removal) {
+                on_write(ansi::remove_ansi_escape_codes(str));
+            } else {
+                on_write(str);
+            }
         }
     };
     m_backend->on_autocomplete = [this](lk::Backend&, std::string str, int n) {

src/commandline.h

@@ -25,6 +25,14 @@ class Commandline final {
     void enable_key_debug() { m_backend->enable_key_debug(); }
     void disable_key_debug() { m_backend->disable_key_debug(); }
 
+    /// Enable the removal of ANSI escape codes from all writes before submitting them to the
+    /// on_write callback. For example, this can be used to remove color codes before getting the
+    /// string back through the on_write callback to be logged.
+    /// This is disabled by default.
+    void enable_ansi_escape_removal_on_write() { m_ansi_escape_removal = true; }
+    /// Opposite of enable_ansi_escape_for_write.
+    void disable_ansi_escape_removal_on_write() { m_ansi_escape_removal = false; }
+
     // gets called when a command is ready
     std::function<void(Commandline&)> on_command { nullptr };
 
@@ -36,4 +44,5 @@ class Commandline final {
 
 private:
     std::unique_ptr<lk::Backend> m_backend;
-};
+    bool m_ansi_escape_removal = false;
+};

src/helper/ansi.cpp

@@ -0,0 +1,81 @@
+#include "ansi.h"
+#include <string>
+
+enum class State {
+    Normal,
+    Escaped,
+};
+
+std::string ansi::remove_ansi_escape_codes(const std::string& original) {
+    std::string new_str {};
+    new_str.reserve(original.size());
+
+    State state = State::Normal;
+
+    for (size_t i = 0; i < original.size(); ++i) {
+        if (state == State::Normal && original[i] == '\x1b') {
+            state = State::Escaped;
+            continue;
+        }
+
+        if (state == State::Escaped) {
+            switch (original[i]) {
+            case 'A': // Up
+            case 'B': // Down
+            case 'C': // Right
+            case 'D': // Left
+            case 'E': // Next line
+            case 'F': // Previous line
+            case 'G': // Set column
+            case 'H': // Set cursor position
+            case 'J': // Erase display
+            case 'K': // Erase line
+            case 'T': // Scroll down
+            case 'f': // Cursor position
+            case 'm': // Graphics mode
+                state = State::Normal;
+                continue;
+            }
+        }
+
+        if (state == State::Normal) {
+            new_str.push_back(original[i]);
+        }
+    }
+
+    return new_str;
+}
+
+#include "doctest.h"
+
+TEST_CASE("ansi removal") {
+    CHECK(ansi::remove_ansi_escape_codes("hello") == "hello");
+    // Colors
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[1;2mhello world") == "hello world");
+    // Cursor up
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[Ahello\nworld") == "hello\nworld");
+    // Cursor down
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[Bfoo bar") == "foo bar");
+    // Cursor right
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[Cfoo\nbar") == "foo\nbar");
+    // Cursor left
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[Dfoo\tbar") == "foo\tbar");
+    // Next line
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[Efoo\rbar") == "foo\rbar");
+    // Previous line
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[Fhello world!") == "hello world!");
+    // Set column
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[Gfoo bar baz") == "foo bar baz");
+    // Set cursor position
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[Hfoo\nbar\nbaz") == "foo\nbar\nbaz");
+    // Erase display
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[Jfoo\tbar\tbaz") == "foo\tbar\tbaz");
+    // Erase line
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[Kfoo\rbar\rbaz") == "foo\rbar\rbaz");
+    // Scroll down
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[Thello\nworld!") == "hello\nworld!");
+    // Cursor position (alternative)
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[fhello\tworld!") == "hello\tworld!");
+    // Graphics mode
+    CHECK(ansi::remove_ansi_escape_codes("\x1b[mfoo bar baz") == "foo bar baz");
+}

src/helper/ansi.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <string>
+
+namespace ansi {
+
+std::string remove_ansi_escape_codes(const std::string& input);
+
+}