Page: refactor GetTitle() to take std::span and return std::string_view

src/ChatPage.cxx

@@ -45,7 +45,7 @@ class ChatPage final : public TextPage {
 	void Update(struct mpdclient &c, unsigned events) noexcept override;
 	bool OnCommand(struct mpdclient &c, Command cmd) override;
 
-	const char *GetTitle(char *, size_t) const noexcept override {
+	std::string_view GetTitle(std::span<char>) const noexcept override {
 		return _("Chat");
 	}
 };

src/EditPlaylistPage.cxx

@@ -12,6 +12,7 @@
 #include "Options.hxx"
 #include "mpdclient.hxx"
 #include "screen.hxx"
+#include "util/SPrintf.hxx"
 
 #include <mpd/client.h>
 
@@ -50,7 +51,7 @@ class EditPlaylistPage final : public FileListPage {
 	bool OnMouse(struct mpdclient &c, Point p, mmask_t bstate) override;
 #endif
 
-	const char *GetTitle(char *s, size_t size) const noexcept override;
+	std::string_view GetTitle(std::span<char> buffer) const noexcept override;
 };
 
 static bool
@@ -112,14 +113,13 @@ edit_playlist_page_init(ScreenManager &_screen, const Window window, Size size)
 	return std::make_unique<EditPlaylistPage>(_screen, window, size);
 }
 
-const char *
-EditPlaylistPage::GetTitle(char *str, size_t size) const noexcept
+std::string_view
+EditPlaylistPage::GetTitle(std::span<char> buffer) const noexcept
 {
 	if (name.empty())
 		return _("Playlist");
 
-	snprintf(str, size, "%s: %s", _("Playlist"), name.c_str());
-	return str;
+	return SPrintf(buffer, "%s: %s", _("Playlist"), name.c_str());
 }
 
 void

src/FileBrowserPage.cxx

@@ -16,6 +16,7 @@
 #include "screen_client.hxx"
 #include "Command.hxx"
 #include "Options.hxx"
+#include "util/SPrintf.hxx"
 #include "util/UriUtil.hxx"
 
 #include <mpd/client.h>
@@ -68,7 +69,7 @@ class FileBrowserPage final : public FileListPage {
 	/* virtual methods from class Page */
 	void Update(struct mpdclient &c, unsigned events) noexcept override;
 	bool OnCommand(struct mpdclient &c, Command cmd) override;
-	const char *GetTitle(char *s, size_t size) const noexcept override;
+	std::string_view GetTitle(std::span<char> buffer) const noexcept override;
 };
 
 static void
@@ -270,8 +271,8 @@ screen_file_init(ScreenManager &_screen, const Window window, Size size) noexcep
 	return std::make_unique<FileBrowserPage>(_screen, window, size);
 }
 
-const char *
-FileBrowserPage::GetTitle(char *str, size_t size) const noexcept
+std::string_view
+FileBrowserPage::GetTitle(std::span<char> buffer) const noexcept
 {
 	const char *path = nullptr, *prev = nullptr, *slash = current_path.c_str();
 
@@ -285,10 +286,9 @@ FileBrowserPage::GetTitle(char *str, size_t size) const noexcept
 		/* fall back to full path */
 		path = current_path.c_str();
 
-	snprintf(str, size, "%s: %s",
-		 /* translators: caption of the browser screen */
-		 _("Browse"), Utf8ToLocale(path).c_str());
-	return str;
+	return SPrintf(buffer, "%s: %s",
+		       /* translators: caption of the browser screen */
+		       _("Browse"), Utf8ToLocale(path).c_str());
 }
 
 void

src/HelpPage.cxx

@@ -229,7 +229,7 @@ class HelpPage final : public ListPage, ListRenderer, ListText {
 	void Paint() const noexcept override;
 	bool OnCommand(struct mpdclient &c, Command cmd) override;
 
-	const char *GetTitle(char *, size_t) const noexcept override {
+	std::string_view GetTitle(std::span<char>) const noexcept override {
 		return _("Help");
 	}
 };

src/KeyDefPage.cxx

@@ -111,7 +111,7 @@ class CommandKeysPage final : public ListPage, ListText {
 	void OnOpen(struct mpdclient &c) noexcept override;
 	void Paint() const noexcept override;
 	bool OnCommand(struct mpdclient &c, Command cmd) override;
-	const char *GetTitle(char *s, size_t size) const noexcept override;
+	std::string_view GetTitle(std::span<char> buffer) const noexcept override;
 
 private:
 	/* virtual methods from class ListText */
@@ -228,12 +228,11 @@ CommandKeysPage::OnOpen([[maybe_unused]] struct mpdclient &c) noexcept
 	// TODO
 }
 
-const char *
-CommandKeysPage::GetTitle(char *str, size_t size) const noexcept
+std::string_view
+CommandKeysPage::GetTitle(std::span<char> buffer) const noexcept
 {
-	snprintf(str, size, _("Edit keys for %s"),
-		 get_key_command_name(Command(subcmd)));
-	return str;
+	return SPrintf(buffer, _("Edit keys for %s"),
+		       get_key_command_name(Command(subcmd)));
 }
 
 void
@@ -347,7 +346,7 @@ class CommandListPage final : public ListPage, ListText {
 	void OnOpen(struct mpdclient &c) noexcept override;
 	void Paint() const noexcept override;
 	bool OnCommand(struct mpdclient &c, Command cmd) override;
-	const char *GetTitle(char *s, size_t size) const noexcept override;
+	std::string_view GetTitle(std::span<char> buffer) const noexcept override;
 
 private:
 	/* virtual methods from class ListText */
@@ -446,8 +445,8 @@ CommandListPage::OnOpen([[maybe_unused]] struct mpdclient &c) noexcept
 	lw.SetLength(command_length());
 }
 
-const char *
-CommandListPage::GetTitle(char *, size_t) const noexcept
+std::string_view
+CommandListPage::GetTitle(std::span<char>) const noexcept
 {
 	return _("Edit key bindings");
 }

src/LibraryPage.cxx

@@ -12,6 +12,7 @@
 #include "mpdclient.hxx"
 #include "filelist.hxx"
 #include "Options.hxx"
+#include "util/SPrintf.hxx"
 
 #include <list>
 #include <string>
@@ -36,16 +37,15 @@ GetTagPlural(enum mpd_tag_type tag) noexcept
 	}
 }
 
-static const char *
-MakePageTitle(char *buffer, size_t size, const char *prefix,
+static std::string_view 
+MakePageTitle(std::span<char> buffer, const char *prefix,
 	      const TagFilter &filter)
 {
 	if (filter.empty())
 		return prefix;
 
-	snprintf(buffer, size, "%s: %s", prefix,
-		 Utf8ToLocale(ToString(filter).c_str()).c_str());
-	return buffer;
+	return SPrintf(buffer, "%s: %s", prefix,
+		       Utf8ToLocale(ToString(filter).c_str()).c_str());
 }
 
 class SongListPage final : public FileListPage {
@@ -80,7 +80,7 @@ class SongListPage final : public FileListPage {
 	/* virtual methods from class Page */
 	void Update(struct mpdclient &c, unsigned events) noexcept override;
 	bool OnCommand(struct mpdclient &c, Command cmd) override;
-	const char *GetTitle(char *s, size_t size) const noexcept override;
+	std::string_view GetTitle(std::span<char> buffer) const noexcept override;
 };
 
 void
@@ -181,7 +181,7 @@ ArtistBrowserPage::OpenTagPage(struct mpdclient &c,
 	page->SetFilter(std::move(filter));
 
 	char buffer[64];
-	page->SetTitle(MakePageTitle(buffer, sizeof(buffer),
+	page->SetTitle(MakePageTitle(buffer,
 				     _("Albums"),
 				     page->GetFilter()));
 
@@ -201,10 +201,10 @@ InitLibraryPage(ScreenManager &_screen, const Window window, Size size)
 	return std::make_unique<ArtistBrowserPage>(_screen, window, size);
 }
 
-const char *
-SongListPage::GetTitle(char *str, size_t size) const noexcept
+std::string_view
+SongListPage::GetTitle(std::span<char> buffer) const noexcept
 {
-	return MakePageTitle(str, size, _("Songs"), filter);
+	return MakePageTitle(buffer, _("Songs"), filter);
 }
 
 bool

src/LyricsPage.cxx

@@ -17,6 +17,7 @@
 #include "TextPage.hxx"
 #include "screen_utils.hxx"
 #include "ncu.hxx"
+#include "util/SPrintf.hxx"
 #include "util/StringAPI.hxx"
 
 #include <string>
@@ -113,7 +114,7 @@ class LyricsPage final : public TextPage, PluginResponseHandler {
 	void OnOpen(struct mpdclient &c) noexcept override;
 	void Update(struct mpdclient &c, unsigned events) noexcept override;
 	bool OnCommand(struct mpdclient &c, Command cmd) override;
-	const char *GetTitle(char *, size_t) const noexcept override;
+	std::string_view GetTitle(std::span<char> buffer) const noexcept override;
 
 private:
 	/* virtual methods from class PluginResponseHandler */
@@ -308,28 +309,26 @@ LyricsPage::Update(struct mpdclient &c, unsigned) noexcept
 		MaybeLoad(c.GetPlayingSong());
 }
 
-const char *
-LyricsPage::GetTitle(char *str, size_t size) const noexcept
+std::string_view
+LyricsPage::GetTitle(std::span<char> buffer) const noexcept
 {
 	if (plugin_cycle != nullptr) {
-		snprintf(str, size, "%s (%s)",
-			 _("Lyrics"),
-			 /* translators: this message is displayed
-			    while data is retrieved */
-			 _("loading..."));
-		return str;
+		return SPrintf(buffer, "%s (%s)",
+			       _("Lyrics"),
+			       /* translators: this message is displayed
+				  while data is retrieved */
+			       _("loading..."));
 	} else if (artist != nullptr && title != nullptr && !IsEmpty()) {
-		int n;
-		n = snprintf(str, size, "%s: %s - %s",
+		std::size_t n;
+		n = snprintf(buffer.data(), buffer.size(), "%s: %s - %s",
 			     _("Lyrics"),
 			     artist, title);
 
 		if (options.lyrics_show_plugin && !plugin_name.empty() &&
-		    (unsigned int) n < size - 1)
-			snprintf(str + n, size - n, " (%s)",
-				 plugin_name.c_str());
+		    n < buffer.size() - 1)
+			n += snprintf(buffer.data() + n, buffer.size() - n, " (%s)", plugin_name.c_str());
 
-		return str;
+		return {buffer.data(), n};
 	} else
 		return _("Lyrics");
 }

src/OutputsPage.cxx

@@ -129,7 +129,7 @@ class OutputsPage final : public ListPage, ListRenderer {
 	void Paint() const noexcept override;
 	void Update(struct mpdclient &c, unsigned events) noexcept override;
 	bool OnCommand(struct mpdclient &c, Command cmd) override;
-	const char *GetTitle(char *s, size_t size) const noexcept override;
+	std::string_view GetTitle(std::span<char> buffer) const noexcept override;
 
 	/* virtual methods from class ListRenderer */
 	void PaintListItem(Window window, unsigned i, unsigned y, unsigned width,
@@ -351,8 +351,8 @@ outputs_init(ScreenManager &screen, const Window window, Size size)
 	return std::make_unique<OutputsPage>(screen, window, size);
 }
 
-const char *
-OutputsPage::GetTitle(char *, size_t) const noexcept
+std::string_view 
+OutputsPage::GetTitle(std::span<char>) const noexcept
 {
 	return _("Outputs");
 }

src/Page.hxx

@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 // Copyright The Music Player Daemon Project
 
-#ifndef NCMPC_PAGE_HXX
-#define NCMPC_PAGE_HXX
+#pragma once
 
 #include "config.h"
 #include "Point.hxx"
@@ -11,8 +10,8 @@
 #include <curses.h>
 
 #include <utility>
-
-#include <stddef.h>
+#include <span>
+#include <string_view>
 
 enum class Command : unsigned;
 struct mpdclient;
@@ -111,7 +110,5 @@ public:
 #endif
 
 	[[gnu::pure]]
-	virtual const char *GetTitle(char *s, size_t size) const noexcept = 0;
+	virtual std::string_view GetTitle(std::span<char> buffer) const noexcept = 0;
 };
-
-#endif

src/ProxyPage.cxx

@@ -97,10 +97,10 @@ ProxyPage::OnMouse(struct mpdclient &c, Point p, mmask_t bstate)
 }
 #endif
 
-const char *
-ProxyPage::GetTitle(char *s, size_t size) const noexcept
+std::string_view
+ProxyPage::GetTitle(std::span<char> buffer) const noexcept
 {
 	return current_page != nullptr
-		? current_page->GetTitle(s, size)
-		: "";
+		? current_page->GetTitle(buffer)
+		: std::string_view{};
 }

src/ProxyPage.hxx

@@ -49,5 +49,5 @@ public:
 	bool OnMouse(struct mpdclient &c, Point p, mmask_t bstate) override;
 #endif
 
-	const char *GetTitle(char *s, size_t size) const noexcept override;
+	std::string_view GetTitle(std::span<char> buffer) const noexcept override;
 };

src/QueuePage.cxx

@@ -27,6 +27,7 @@
 #include "LyricsPage.hxx"
 #include "db_completion.hxx"
 #include "event/CoarseTimerEvent.hxx"
+#include "util/SPrintf.hxx"
 
 #ifndef NCMPC_MINI
 #include "hscroll.hxx"
@@ -138,7 +139,7 @@ class QueuePage final : public ListPage, ListRenderer, ListText {
 	bool OnMouse(struct mpdclient &c, Point p, mmask_t bstate) override;
 #endif
 
-	const char *GetTitle(char *s, size_t size) const noexcept override;
+	std::string_view GetTitle(std::span<char> buffer) const noexcept override;
 };
 
 const struct mpd_song *
@@ -368,14 +369,13 @@ QueuePage::OnClose() noexcept
 #endif
 }
 
-const char *
-QueuePage::GetTitle(char *str, size_t size) const noexcept
+std::string_view
+QueuePage::GetTitle(std::span<char> buffer) const noexcept
 {
 	if (connection_name.empty())
 		return _("Queue");
 
-	snprintf(str, size, _("Queue on %s"), connection_name.c_str());
-	return str;
+	return SPrintf(buffer, _("Queue on %s"), connection_name.c_str());
 }
 
 void