From 78a9c17bc6d7c6c5099a30de77636a551fd52362 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max.kellermann@gmail.com>
Date: Sun, 12 Mar 2023 08:55:16 +0100
Subject: [PATCH] decoder/plugin: add "suffixes" function

For decoder plugins like FFmpeg where the supported codecs cannot be
determined at compile time.
---
 src/CommandLine.cxx           |  4 ++++
 src/decoder/DecoderPlugin.cxx |  6 ++++--
 src/decoder/DecoderPlugin.hxx | 13 +++++++++++++
 src/decoder/DecoderPrint.cxx  |  4 ++++
 4 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/src/CommandLine.cxx b/src/CommandLine.cxx
index 91601fb37..49298e593 100644
--- a/src/CommandLine.cxx
+++ b/src/CommandLine.cxx
@@ -147,6 +147,10 @@ static void version()
 			for (; *suffixes != nullptr; ++suffixes)
 				fmt::print(" {}", *suffixes);
 
+		if (plugin.suffixes_function != nullptr)
+			for (const auto &i : plugin.suffixes_function())
+				printf(" %s", i.c_str());
+
 		if (plugin.protocols != nullptr)
 			for (const auto &i : plugin.protocols())
 				fmt::print(" {}", i);
diff --git a/src/decoder/DecoderPlugin.cxx b/src/decoder/DecoderPlugin.cxx
index 3b54380e9..b96510a00 100644
--- a/src/decoder/DecoderPlugin.cxx
+++ b/src/decoder/DecoderPlugin.cxx
@@ -23,8 +23,10 @@ DecoderPlugin::SupportsUri(const char *uri) const noexcept
 bool
 DecoderPlugin::SupportsSuffix(std::string_view suffix) const noexcept
 {
-	return suffixes != nullptr &&
-		StringArrayContainsCase(suffixes, suffix);
+	return (suffixes != nullptr &&
+		StringArrayContainsCase(suffixes, suffix)) ||
+		(suffixes_function != nullptr &&
+		 suffixes_function().contains(suffix));
 }
 
 bool
diff --git a/src/decoder/DecoderPlugin.hxx b/src/decoder/DecoderPlugin.hxx
index 67b838952..b1a1e3ea3 100644
--- a/src/decoder/DecoderPlugin.hxx
+++ b/src/decoder/DecoderPlugin.hxx
@@ -35,6 +35,13 @@ struct DecoderPlugin {
 	 */
 	void (*finish)() noexcept = nullptr;
 
+	/**
+	 * Return a set of supported filename suffixes.  Use this
+	 * instead of #suffixes if the supported suffixes can only be
+	 * determined at runtime.
+	 */
+	std::set<std::string, std::less<>> (*suffixes_function)() noexcept = nullptr;
+
 	/**
 	 * Return a set of supported protocols.
 	 */
@@ -152,6 +159,12 @@ struct DecoderPlugin {
 		return copy;
 	}
 
+	constexpr auto WithSuffixes(std::set<std::string, std::less<>> (*_suffixes)() noexcept) const noexcept {
+		auto copy = *this;
+		copy.suffixes_function = _suffixes;
+		return copy;
+	}
+
 	constexpr auto WithMimeTypes(const char *const*_mime_types) const noexcept {
 		auto copy = *this;
 		copy.mime_types = _mime_types;
diff --git a/src/decoder/DecoderPrint.cxx b/src/decoder/DecoderPrint.cxx
index ab96973c8..81f016b21 100644
--- a/src/decoder/DecoderPrint.cxx
+++ b/src/decoder/DecoderPrint.cxx
@@ -25,6 +25,10 @@ decoder_plugin_print(Response &r,
 		for (p = plugin.suffixes; *p != nullptr; ++p)
 			r.Fmt(FMT_STRING("suffix: {}\n"), *p);
 
+	if (plugin.suffixes_function != nullptr)
+		for (const auto &i : plugin.suffixes_function())
+			r.Fmt(FMT_STRING("suffix: {}\n"), i);
+
 	if (plugin.mime_types != nullptr)
 		for (p = plugin.mime_types; *p != nullptr; ++p)
 			r.Fmt(FMT_STRING("mime_type: {}\n"), *p);