Merge pull request #2852 from dpayne/add_css_reload

Adding css reloader

include/client.hpp

@@ -7,6 +7,7 @@
 
 #include "bar.hpp"
 #include "config.hpp"
+#include "util/css_reload_helper.hpp"
 #include "util/portal.hpp"
 
 struct zwlr_layer_shell_v1;
@@ -55,6 +56,8 @@ class Client {
   Glib::RefPtr<Gtk::CssProvider> css_provider_;
   std::unique_ptr<Portal> portal;
   std::list<struct waybar_output> outputs_;
+  std::unique_ptr<CssReloadHelper> m_cssReloadHelper;
+  std::string m_cssFile;
 };
 
 }  // namespace waybar

include/util/css_reload_helper.hpp

@@ -0,0 +1,47 @@
+#pragma once
+
+#include <functional>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include "giomm/file.h"
+#include "giomm/filemonitor.h"
+#include "glibmm/refptr.h"
+
+struct pollfd;
+
+namespace waybar {
+class CssReloadHelper {
+ public:
+  CssReloadHelper(std::string cssFile, std::function<void()> callback);
+
+  virtual void monitorChanges();
+
+ protected:
+  std::vector<std::string> parseImports(const std::string& cssFile);
+
+  void parseImports(const std::string& cssFile, std::unordered_map<std::string, bool>& imports);
+
+  void watchFiles(const std::vector<std::string>& files);
+
+  bool handleInotifyEvents(int fd);
+
+  bool watch(int inotifyFd, pollfd* pollFd);
+
+  virtual std::string getFileContents(const std::string& filename);
+
+  virtual std::string findPath(const std::string& filename);
+
+  void handleFileChange(Glib::RefPtr<Gio::File> const& file,
+                        Glib::RefPtr<Gio::File> const& other_type,
+                        Gio::FileMonitorEvent event_type);
+
+ private:
+  std::string m_cssFile;
+
+  std::function<void()> m_callback;
+
+  std::vector<std::tuple<Glib::RefPtr<Gio::FileMonitor>>> m_fileMonitors;
+};
+}  // namespace waybar

man/waybar.5.scd.in

@@ -130,6 +130,11 @@ Also, a minimal example configuration can be found at the bottom of this man pag
 	Each file can contain a single object with any of the bar configuration options. In case of duplicate options, the first defined value takes precedence, i.e. including file -> first included file -> etc. Nested includes are permitted, but make sure to avoid circular imports.
 	For a multi-bar config, the include directive affects only current bar configuration object.
 
+*reload_style_on_change* ++
+	typeof: bool ++
+	default: *false* ++
+	Option to enable reloading the css style if a modification is detected on the style sheet file or any imported css files.
+
 # MODULE FORMAT
 
 You can use PangoMarkupFormat (See https://developer.gnome.org/pango/stable/PangoMarkupFormat.html#PangoMarkupFormat).

meson.build

@@ -196,7 +196,8 @@ src_files = files(
     'src/util/sanitize_str.cpp',
     'src/util/rewrite_string.cpp',
     'src/util/gtk_icon.cpp',
-    'src/util/regex_collection.cpp'
+    'src/util/regex_collection.cpp',
+    'src/util/css_reload_helper.cpp'
 )
 
 inc_dirs = ['include']

src/client.cpp

@@ -262,15 +262,21 @@ int waybar::Client::main(int argc, char *argv[]) {
   if (!portal) {
     portal = std::make_unique<waybar::Portal>();
   }
-  auto css_file = getStyle(style_opt);
+  m_cssFile = getStyle(style_opt);
-  setupCss(css_file);
+  setupCss(m_cssFile);
+  m_cssReloadHelper = std::make_unique<CssReloadHelper>(m_cssFile, [&]() { setupCss(m_cssFile); });
   portal->signal_appearance_changed().connect([&](waybar::Appearance appearance) {
     auto css_file = getStyle(style_opt, appearance);
     setupCss(css_file);
   });
+
+  if (config.getConfig()["reload_style_on_change"].asBool()) {
+    m_cssReloadHelper->monitorChanges();
+  }
   bindInterfaces();
   gtk_app->hold();
   gtk_app->run();
+  m_cssReloadHelper.reset();  // stop watching css file
   bars.clear();
   return 0;
 }

src/util/css_reload_helper.cpp

@@ -0,0 +1,144 @@
+#include "util/css_reload_helper.hpp"
+
+#include <poll.h>
+#include <spdlog/spdlog.h>
+#include <sys/inotify.h>
+
+#include <filesystem>
+#include <fstream>
+#include <regex>
+#include <unordered_map>
+
+#include "config.hpp"
+#include "giomm/file.h"
+#include "glibmm/refptr.h"
+
+namespace {
+const std::regex IMPORT_REGEX(R"(@import\s+(?:url\()?(?:"|')([^"')]+)(?:"|')\)?;)");
+}
+
+waybar::CssReloadHelper::CssReloadHelper(std::string cssFile, std::function<void()> callback)
+    : m_cssFile(std::move(cssFile)), m_callback(std::move(callback)) {}
+
+std::string waybar::CssReloadHelper::getFileContents(const std::string& filename) {
+  if (filename.empty()) {
+    return {};
+  }
+
+  std::ifstream file(filename);
+  if (!file.is_open()) {
+    return {};
+  }
+
+  return {(std::istreambuf_iterator<char>(file)), std::istreambuf_iterator<char>()};
+}
+
+std::string waybar::CssReloadHelper::findPath(const std::string& filename) {
+  // try path and fallback to looking relative to the config
+  std::string result;
+  if (std::filesystem::exists(filename)) {
+    result = filename;
+  } else {
+    result = Config::findConfigPath({filename}).value_or("");
+  }
+
+  // File monitor does not work with symlinks, so resolve them
+  if (std::filesystem::is_symlink(result)) {
+    result = std::filesystem::read_symlink(result);
+  }
+
+  return result;
+}
+
+void waybar::CssReloadHelper::monitorChanges() {
+  auto files = parseImports(m_cssFile);
+  for (const auto& file : files) {
+    auto gioFile = Gio::File::create_for_path(file);
+    if (!gioFile) {
+      spdlog::error("Failed to create file for path: {}", file);
+      continue;
+    }
+
+    auto fileMonitor = gioFile->monitor_file();
+    if (!fileMonitor) {
+      spdlog::error("Failed to create file monitor for path: {}", file);
+      continue;
+    }
+
+    auto connection = fileMonitor->signal_changed().connect(
+        sigc::mem_fun(*this, &CssReloadHelper::handleFileChange));
+
+    if (!connection.connected()) {
+      spdlog::error("Failed to connect to file monitor for path: {}", file);
+      continue;
+    }
+    m_fileMonitors.emplace_back(std::move(fileMonitor));
+  }
+}
+
+void waybar::CssReloadHelper::handleFileChange(Glib::RefPtr<Gio::File> const& file,
+                                               Glib::RefPtr<Gio::File> const& other_type,
+                                               Gio::FileMonitorEvent event_type) {
+  // Multiple events are fired on file changed (attributes, write, changes done hint, etc.), only
+  // fire for one
+  if (event_type == Gio::FileMonitorEvent::FILE_MONITOR_EVENT_CHANGES_DONE_HINT) {
+    spdlog::debug("Reloading style, file changed: {}", file->get_path());
+    m_callback();
+  }
+}
+
+std::vector<std::string> waybar::CssReloadHelper::parseImports(const std::string& cssFile) {
+  std::unordered_map<std::string, bool> imports;
+
+  auto cssFullPath = findPath(cssFile);
+  if (cssFullPath.empty()) {
+    spdlog::error("Failed to find css file: {}", cssFile);
+    return {};
+  }
+
+  spdlog::debug("Parsing imports for file: {}", cssFullPath);
+  imports[cssFullPath] = false;
+
+  auto previousSize = 0UL;
+  auto maxIterations = 100U;
+  do {
+    previousSize = imports.size();
+    for (const auto& [file, parsed] : imports) {
+      if (!parsed) {
+        parseImports(file, imports);
+      }
+    }
+
+  } while (imports.size() > previousSize && maxIterations-- > 0);
+
+  std::vector<std::string> result;
+  for (const auto& [file, parsed] : imports) {
+    if (parsed) {
+      spdlog::debug("Adding file to watch list: {}", file);
+      result.push_back(file);
+    }
+  }
+
+  return result;
+}
+
+void waybar::CssReloadHelper::parseImports(const std::string& cssFile,
+                                           std::unordered_map<std::string, bool>& imports) {
+  // if the file has already been parsed, skip
+  if (imports.find(cssFile) != imports.end() && imports[cssFile]) {
+    return;
+  }
+
+  auto contents = getFileContents(cssFile);
+  std::smatch matches;
+  while (std::regex_search(contents, matches, IMPORT_REGEX)) {
+    auto importFile = findPath({matches[1].str()});
+    if (!importFile.empty() && imports.find(importFile) == imports.end()) {
+      imports[importFile] = false;
+    }
+
+    contents = matches.suffix().str();
+  }
+
+  imports[cssFile] = true;
+}

test/css_reload_helper.cpp

@@ -0,0 +1,101 @@
+#include "util/css_reload_helper.hpp"
+
+#include <map>
+
+#if __has_include(<catch2/catch_test_macros.hpp>)
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers_all.hpp>
+#else
+#include <catch2/catch.hpp>
+#endif
+
+class CssReloadHelperTest : public waybar::CssReloadHelper {
+ public:
+  CssReloadHelperTest() : CssReloadHelper("/tmp/waybar_test.css", [this]() { callback(); }) {}
+
+  void callback() { m_callbackCounter++; }
+
+ protected:
+  std::string getFileContents(const std::string& filename) override {
+    return m_fileContents[filename];
+  }
+
+  std::string findPath(const std::string& filename) override { return filename; }
+
+  void setFileContents(const std::string& filename, const std::string& contents) {
+    m_fileContents[filename] = contents;
+  }
+
+  int getCallbackCounter() const { return m_callbackCounter; }
+
+ private:
+  int m_callbackCounter{};
+  std::map<std::string, std::string> m_fileContents;
+};
+
+TEST_CASE_METHOD(CssReloadHelperTest, "parse_imports", "[util][css_reload_helper]") {
+  SECTION("no imports") {
+    setFileContents("/tmp/waybar_test.css", "body { color: red; }");
+    auto files = parseImports("/tmp/waybar_test.css");
+    REQUIRE(files.size() == 1);
+    CHECK(files[0] == "/tmp/waybar_test.css");
+  }
+
+  SECTION("single import") {
+    setFileContents("/tmp/waybar_test.css", "@import 'test.css';");
+    setFileContents("test.css", "body { color: red; }");
+    auto files = parseImports("/tmp/waybar_test.css");
+    std::sort(files.begin(), files.end());
+    REQUIRE(files.size() == 2);
+    CHECK(files[0] == "/tmp/waybar_test.css");
+    CHECK(files[1] == "test.css");
+  }
+
+  SECTION("multiple imports") {
+    setFileContents("/tmp/waybar_test.css", "@import 'test.css'; @import 'test2.css';");
+    setFileContents("test.css", "body { color: red; }");
+    setFileContents("test2.css", "body { color: blue; }");
+    auto files = parseImports("/tmp/waybar_test.css");
+    std::sort(files.begin(), files.end());
+    REQUIRE(files.size() == 3);
+    CHECK(files[0] == "/tmp/waybar_test.css");
+    CHECK(files[1] == "test.css");
+    CHECK(files[2] == "test2.css");
+  }
+
+  SECTION("nested imports") {
+    setFileContents("/tmp/waybar_test.css", "@import 'test.css';");
+    setFileContents("test.css", "@import 'test2.css';");
+    setFileContents("test2.css", "body { color: red; }");
+    auto files = parseImports("/tmp/waybar_test.css");
+    std::sort(files.begin(), files.end());
+    REQUIRE(files.size() == 3);
+    CHECK(files[0] == "/tmp/waybar_test.css");
+    CHECK(files[1] == "test.css");
+    CHECK(files[2] == "test2.css");
+  }
+
+  SECTION("circular imports") {
+    setFileContents("/tmp/waybar_test.css", "@import 'test.css';");
+    setFileContents("test.css", "@import 'test2.css';");
+    setFileContents("test2.css", "@import 'test.css';");
+    auto files = parseImports("/tmp/waybar_test.css");
+    std::sort(files.begin(), files.end());
+    REQUIRE(files.size() == 3);
+    CHECK(files[0] == "/tmp/waybar_test.css");
+    CHECK(files[1] == "test.css");
+    CHECK(files[2] == "test2.css");
+  }
+
+  SECTION("empty") {
+    setFileContents("/tmp/waybar_test.css", "");
+    auto files = parseImports("/tmp/waybar_test.css");
+    REQUIRE(files.size() == 1);
+    CHECK(files[0] == "/tmp/waybar_test.css");
+  }
+
+  SECTION("empty name") {
+    auto files = parseImports("");
+    REQUIRE(files.empty());
+  }
+}

test/meson.build

@@ -11,7 +11,9 @@ test_src = files(
     'JsonParser.cpp',
     'SafeSignal.cpp',
     'config.cpp',
+    'css_reload_helper.cpp',
     '../src/config.cpp',
+    '../src/util/css_reload_helper.cpp',
 )
 
 if tz_dep.found()