message: support cooked/raw filenames

Supported a "cooked" mode for attachment filenames, which gets rid of any
unacceptable characters. Add "raw_filename" to get the filename as specified in
the part.

Update tests.

lib/message/mu-message-part.cc

@@ -19,6 +19,7 @@
 
 
 #include "mu-message-part.hh"
+#include "glibconfig.h"
 #include "mu-mime-object.hh"
 #include "utils/mu-utils.hh"
 
@@ -36,7 +37,41 @@ MessagePart::~MessagePart() = default;
 
 
 Option<std::string>
-MessagePart::filename() const noexcept
+MessagePart::cooked_filename() const noexcept
+{
+	// make a bit more pallatble.
+	auto cleanup = [](const std::string& name)->std::string {
+		std::string clean;
+		clean.reserve(name.length());
+		for (auto& c: name) {
+			auto taboo{(::iscntrl(c) || c == G_DIR_SEPARATOR ||
+				    c == ' ' || c == '\\' || c == ':')};
+			clean += (taboo ? '-' : c);
+		}
+		if (clean.size() > 1 && clean[0] == '-')
+			clean.erase(0, 1);
+
+		return clean;
+	};
+
+	// a MimePart... use the name if there is one.
+	if (mime_obj->is_part())
+		return MimePart(*mime_obj).filename().map(cleanup);
+
+	// MimeMessagepart. Construct a name based on subject.
+	if (mime_obj->is_message_part()) {
+		auto msg{MimeMessagePart(*mime_obj).get_message()};
+		return msg.subject()
+			.map(cleanup)
+			.value_or("no-subject") + ".eml";
+	}
+
+return Nothing;
+
+}
+
+Option<std::string>
+MessagePart::raw_filename() const noexcept
 {
 	if (!mime_obj->is_part())
 		return Nothing;
@@ -44,6 +79,8 @@ MessagePart::filename() const noexcept
 		return MimePart(*mime_obj).filename();
 }
 
+
+
 Option<std::string>
 MessagePart::mime_type() const noexcept
 {
@@ -62,6 +99,15 @@ MessagePart::size() const noexcept
 		return MimePart(*mime_obj).size();
 }
 
+bool
+MessagePart::is_attachment() const noexcept
+{
+	if (!mime_obj->is_part())
+		return false;
+	else
+		return MimePart(*mime_obj).is_attachment();
+}
+
 
 Option<std::string>
 MessagePart::to_string() const noexcept

lib/message/mu-message-part.hh

@@ -53,11 +53,23 @@ public:
 	~MessagePart();
 
 	/**
-	 * Filename for the mime-part
+	 * Filename for the mime-part file. This is a "cooked" filename with
+	 * unallowed characters removed. If there's no filename specified,
+	 * construct one (such as in the case of MimeMessagePart).
+	 *
+	 * @see raw_filename()
+	 *
+	 * @return the name
+	 */
+	Option<std::string> cooked_filename() const noexcept;
+
+	/**
+	 * Name for the mime-part file, i.e., MimePart::filename
 	 *
 	 * @return the filename or Nothing if there is none
 	 */
-	Option<std::string> filename() const noexcept;
+	Option<std::string> raw_filename() const noexcept;
+
 
 	/**
 	 * Mime-type for the mime-part (e.g. "text/plain")
@@ -73,6 +85,15 @@ public:
 	 */
 	size_t size() const noexcept;
 
+	/**
+	 * Does this part have an "attachment" disposition? Otherwise it is
+	 * "inline". Note that does *not* map 1:1 to a message's HasAttachment
+	 * flag.
+	 *
+	 * @return true or false.
+	 */
+	bool is_attachment() const noexcept;
+
 	/**
 	 * Write (decoded) mime-part contents to string
 	 *
@@ -80,7 +101,6 @@ public:
 	 */
 	Option<std::string> to_string() const noexcept;
 
-
 	/**
 	 * Write (decoded) mime part to a file
 	 *

lib/message/mu-message.cc

@@ -438,7 +438,7 @@ fill_document(Message::Private& priv)
 			break;
 		case Field::Id::File:
 			for (auto&& part: priv.parts)
-				doc.add(field.id, part.filename());
+				doc.add(field.id, part.raw_filename());
 			break;
 		case Field::Id::Flags:
 			doc.add(priv.flags);
@@ -684,7 +684,7 @@ Content-Description: test file 1
 MDAwAQID
 --=-=-=
 Content-Type: audio/ogg
-Content-Disposition: inline; filename=file-02.bin
+Content-Disposition: inline; filename=/tmp/file-02.bin
 Content-Transfer-Encoding: base64
 
 MDA0BQYH
@@ -721,27 +721,28 @@ R"(Hello,World!)");
 	g_assert_cmpuint(message->parts().size(),==,4);
 	{
 		auto&& part{message->parts().at(0)};
-		g_assert_false(!!part.filename());
+		g_assert_false(!!part.raw_filename());
 		assert_equal(part.mime_type().value(), "text/plain");
 		assert_equal(part.to_string().value(), "Hello,");
 	}
 	{
 		auto&& part{message->parts().at(1)};
-		assert_equal(part.filename().value(), "file-01.bin");
+		assert_equal(part.raw_filename().value(), "file-01.bin");
 		assert_equal(part.mime_type().value(), "image/jpeg");
 		// file consist of 6 bytes "000" 0x01,0x02.0x03.
 		assert_equal(part.to_string().value(), "000\001\002\003");
 	}
 	{
 		auto&& part{message->parts().at(2)};
-		assert_equal(part.filename().value(), "file-02.bin");
+		assert_equal(part.raw_filename().value(), "/tmp/file-02.bin");
+		assert_equal(part.cooked_filename().value(), "tmp-file-02.bin");
 		assert_equal(part.mime_type().value(), "audio/ogg");
 		// file consist of the string "004" followed by 0x5,0x6,0x7.
 		assert_equal(part.to_string().value(), "004\005\006\007");
 	}
 	{
 		auto&& part{message->parts().at(3)};
-		g_assert_false(!!part.filename());
+		g_assert_false(!!part.raw_filename());
 		g_assert_true(!!part.mime_type());
 		assert_equal(part.mime_type().value(), "text/plain");
 		assert_equal(part.to_string().value(), "World!");