message: add cache_path per message

Generate a message-specific cache path when needed.
Update tests, too.

lib/message/mu-message-part.cc

@@ -22,6 +22,7 @@
 #include "glibconfig.h"
 #include "mu-mime-object.hh"
 #include "utils/mu-utils.hh"
+#include <string>
 
 using namespace Mu;
 
@@ -71,8 +72,7 @@ MessagePart::cooked_filename() const noexcept
 			.value_or("no-subject") + ".eml";
 	}
 
-return Nothing;
-
+	return Nothing;
 }
 
 Option<std::string>

lib/message/mu-message.cc

@@ -39,6 +39,7 @@
 
 #include "gmime/gmime-message.h"
 #include "mu-mime-object.hh"
+#include "mu-option.hh"
 
 using namespace Mu;
 
@@ -98,7 +99,7 @@ Message::Message(const std::string& path,  Message::Options opts):
 	if (!statbuf)
 		throw statbuf.error();
 
-	priv_->mtime = statbuf->st_mtime;
+	priv_->ctime = statbuf->st_ctime;
 
 	init_gmime();
 	if (auto msg{MimeMessage::make_from_file(path)}; !msg)
@@ -204,16 +205,16 @@ Message::set_maildir(const std::string& maildir)
 			   "'%s' is not a valid maildir for message @ %s",
 			   maildir.c_str(), path.c_str());
 
+	priv_->doc.remove(Field::Id::Maildir);
 	priv_->doc.add(Field::Id::Maildir, maildir);
 
 	return Ok();
 }
 
-
-
 void
 Message::set_flags(Flags flags)
 {
+	priv_->doc.remove(Field::Id::Flags);
 	priv_->doc.add(flags);
 }
 
@@ -694,13 +695,10 @@ fill_document(Message::Private& priv)
 		case Field::Id::To:
 			doc.add(field.id, mime_msg.contacts(Contact::Type::To));
 			break;
-
 			/* internal fields */
 		case Field::Id::XBodyHtml:
 			doc.add(field.id, priv.body_html);
 			break;
-		case Field::Id::XCachedSexp:
-			break;
 			/* ignore */
 		case Field::Id::_count_:
 			break;
@@ -759,15 +757,24 @@ Message::parts() const
 	return priv_->parts;
 }
 
-::time_t
-Message::mtime() const
+Result<std::string>
+Message::cache_path() const
 {
-	if (!load_mime_message())
-		return 0;
+	/* create tmpdir for this message, if needed */
+	if (priv_->cache_path.empty()) {
+		GError *err{};
+		auto tpath{to_string_opt_gchar(
+				g_dir_make_tmp("mu-message-part-XXXXXX", &err))};
+		if (!tpath)
+			return Err(Error::Code::File, &err,
+				   "failed to create temp dir");
+		priv_->cache_path = std::move(tpath.value());
+	}
 
-	return priv_->mtime;
+	return Ok(std::string{priv_->cache_path});
 }
 
+
 Result<void>
 Message::update_after_move(const std::string& new_path,
 			   const std::string& new_maildir,

lib/message/mu-message.hh

@@ -140,6 +140,14 @@ public:
 	 */
 	const Document& document() const;
 
+
+	/**
+	 * Get the document-id, or 0 if non-existent.
+	 *
+	 * @return document id
+	 */
+	unsigned docid() const;
+
 	/**
 	 * Get the file system path of this message
 	 *
@@ -236,12 +244,12 @@ public:
 	}
 
 	/**
-	 * get the last modification or creation time for this message
+	 * get the last change-time (ctime) for this message
 	 *
-	 * @return message date/time or 0 if unknown
+	 * @return chnage time or 0 if unknown
 	 */
-	::time_t modified() const {
-		return static_cast<::time_t>(document().integer_value(Field::Id::Modified));
+	::time_t changed() const {
+		return static_cast<::time_t>(document().integer_value(Field::Id::Changed));
 	}
 
 	/**
@@ -297,7 +305,8 @@ public:
 	 * @return a list with the tags for this msg. Don't modify/free
 	 */
 	std::vector<std::string> tags() const {
-		return document().string_vec_value(Field::Id::Tags);
+		return document()
+			.string_vec_value(Field::Id::Tags);
 	}
 
 	/**
@@ -306,7 +315,7 @@ public:
 	 * @return sexp or empty.
 	 */
 	std::string cached_sexp() const {
-		return document().string_value(Field::Id::XCachedSexp);
+		return document().cached_sexp();
 	}
 
 	/*
@@ -314,19 +323,20 @@ public:
 	 */
 
 	/**
-	 * convert the message to a Lisp symbolic expression (for further
-	 * processing in e.g. emacs)
+	 * Get the s-expression for this message. Stays valid as long
+	 * as this message is.
 	 *
-	 * @return a Mu::Sexp or a Mu::Sexp::List representing the message.
+	 * @return a Mu::Sexp::List representing the message.
 	 */
-	Mu::Sexp::List to_sexp_list() const;
-	Mu::Sexp       to_sexp() const;
-
+	const Mu::Sexp::List& to_sexp_list() const;
+	Mu::Sexp to_sexp() const {
+		return Sexp::make_list(Sexp::List(to_sexp_list()));
+	}
 
 	/**
 	 * Update the cached sexp for this message which is stored in the
-	 * document.This should be done when the document is complete,
-	 * i.e., immediately before storing it in the database.
+	 * document. This should be done immediately before storing it in the
+	 * database.
 	 *
 	 */
 	void update_cached_sexp();
@@ -369,13 +379,6 @@ public:
 	Option<std::string> header(const std::string& header_field) const;
 
 
-	/**
-	 * Get the mtime for the message file.
-	 *
-	 * @return the mtime
-	 */
-	::time_t mtime() const;
-
 	/**
 	 * Get all contacts for this message.
 	 *
@@ -391,6 +394,16 @@ public:
 	using Part = MessagePart;
 	const std::vector<Part>& parts() const;
 
+
+	/**
+	 * Get the path to a cche directory for this message, which
+	 * is useful for temporarily saving attachments
+	 *
+	 * @return path to a (created) cache directory, or an error.
+	 */
+	Result<std::string> cache_path() const;
+
+
 	/**
 	 * Load the GMime (file) message (for a database-backed message),
 	 * if not already (but see @param reload).

lib/message/test-mu-message.cc

@@ -204,6 +204,9 @@ World!
 
 	assert_equal(message->subject(), "ättächmeñts");
 
+	const auto cache_path{message->cache_path()};
+	g_assert_true(!!cache_path);
+
 	g_assert_cmpuint(message->parts().size(),==,5);
 	{
 		auto&& part{message->parts().at(0)};
@@ -228,6 +231,11 @@ World!
 		assert_equal(part.mime_type().value(), "audio/ogg");
 		// file consistso of 4 bytes 4..7
 		assert_equal(part.to_string().value(), "\004\005\006\007");
+		const auto fpath{*cache_path + part.cooked_filename().value()};
+		const auto res = part.to_file(fpath, true);
+
+		g_assert_cmpuint(*res,==,4);
+		g_assert_cmpuint(::access(fpath.c_str(), R_OK), ==, 0);
 	}
 
 	{