Implement configuration for BufferedInputStream::MAX_SIZE

doc/user.rst

@@ -927,6 +927,9 @@ These settings are various limitations to prevent :program:`MPD` from using too
      - The maximum size a command list. Default is 2048 (2 MiB).
    * - **max_output_buffer_size KBYTES**
      - The maximum size of the output buffer to a client (maximum response size). Default is 8192 (8 MiB).
+   * - **max_buffered_input_stream_size KBYTES**
+     - Network streams of known size read from a server with seek ability and smaller than this size will be entirely read in memory. Larger streams are read by chunks, as needed. The default is 128 MiB, which may be too big for small machines.
+
 
 Buffer Settings
 ^^^^^^^^^^^^^^^

src/config/Option.hxx

@@ -64,6 +64,7 @@ enum class ConfigOption {
 	DESPOTIFY_HIGH_BITRATE,
 
 	MIXRAMP_ANALYZER,
+	MAX_BUFFERED_INPUT_STREAM_SIZE,
 
 	MAX
 };

src/config/Templates.cxx

@@ -61,6 +61,7 @@ const ConfigTemplate config_param_templates[] = {
 	{ "despotify_password", false, true },
 	{ "despotify_high_bitrate", false, true },
 	{ "mixramp_analyzer" },
+	{ "max_buffered_input_stream_size" },
 };
 
 static constexpr unsigned n_config_param_templates =

src/input/BufferedInputStream.cxx

@@ -5,6 +5,8 @@
 
 #include <string.h>
 
+offset_type BufferedInputStream::MAX_SIZE = 128 * 1024 * 1024;
+
 BufferedInputStream::BufferedInputStream(InputStreamPtr _input)
 	:InputStream(_input->GetUriView(), _input->mutex),
 	 BufferingInputStream(std::move(_input))

src/input/BufferedInputStream.hxx

@@ -8,15 +8,16 @@
 #include "BufferingInputStream.hxx"
 
 #include <cassert>
+#include <iostream>
 
 /**
  * A "huge" buffer which remembers the (partial) contents of an
  * #InputStream.  This works only if the #InputStream is a "file", not
  * a "stream"; see IsEligible() for details.
  */
 class BufferedInputStream final : public InputStream, BufferingInputStream {
-	// TODO: make configurable
-	static constexpr offset_type MAX_SIZE = 128 * 1024 * 1024;
+	// Default 128 MB, set in BufferedInputStream.cxx. Configurable, set from Init.cxx
+	static offset_type MAX_SIZE;
 
 public:
 	BufferedInputStream(InputStreamPtr _input);
@@ -46,6 +47,9 @@ public:
 	size_t Read(std::unique_lock<Mutex> &lock,
 		    void *ptr, size_t size) override;
 
+	static void SetMaxSize(offset_type maxsize) noexcept {
+		MAX_SIZE = maxsize;
+	}
 private:
 	/* virtual methods from class BufferingInputStream */
 	void OnBufferAvailable() noexcept override {

src/input/Init.cxx

@@ -4,9 +4,11 @@
 #include "Init.hxx"
 #include "Registry.hxx"
 #include "InputPlugin.hxx"
+#include "BufferedInputStream.hxx"
 #include "config/Data.hxx"
 #include "config/Option.hxx"
 #include "config/Block.hxx"
+#include "config/Parser.hxx"
 #include "Log.hxx"
 #include "PluginUnavailable.hxx"
 #include "lib/fmt/RuntimeError.hxx"
@@ -21,6 +23,7 @@
 #endif
 
 static constexpr Domain input_domain("input");
+static constexpr size_t KILOBYTE = 1024;
 
 void
 input_stream_global_init(const ConfigData &config, EventLoop &event_loop)
@@ -29,6 +32,16 @@ input_stream_global_init(const ConfigData &config, EventLoop &event_loop)
 	InitUringInputPlugin(event_loop);
 #endif
 
+	if (auto *param = config.GetParam(ConfigOption::MAX_BUFFERED_INPUT_STREAM_SIZE)) {
+		offset_type buffer_size = param->With([](const char *s){
+			size_t result = ParseSize(s, KILOBYTE);
+			if (result <= 0)
+				throw FmtRuntimeError("max buffered input size \"{}\" is not a positive integer", s);
+			return result;
+		});
+		BufferedInputStream::SetMaxSize(buffer_size);
+	}
+
 	const ConfigBlock empty;
 
 	for (unsigned i = 0; input_plugins[i] != nullptr; ++i) {