Merge pull request #2852 from dpayne/add_css_reload

Adding css reloader

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);
-  setupCss(css_file);
+  m_cssFile = getStyle(style_opt);
+  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;
+}