[geary/mjog/dovecot-envelope-mailbox-quirk: 5/8] Geary.Imap: Add quirk for Envelope address structure placeholders

[Michael Gratton <mjog src gnome org>]

commit 6a84b0a49ee73d693342f2ac9e661115a00287d1
Author: Michael Gratton <mike vee net>
Date:   Tue Aug 18 11:40:14 2020 +1000

    Geary.Imap: Add quirk for Envelope address structure placeholders
    
    Some servers (e.g. Dovecot) use placeholder strings instead of the empty
    string (e.g. "MISSING_DOMAIN") in FETCH Envelope responses when a
    required address part (e.g. local part, domain) are empty.
    
    This adds a quirk that can be enabled for such servers to check for the
    placeholders and if found, replace them with empty strings.

 src/engine/imap/api/imap-quirks.vala               | 20 ++++++++++++++++
 .../imap/message/imap-fetch-data-specifier.vala    |  4 ++--
 src/engine/imap/parameter/imap-list-parameter.vala | 11 +++++++++
 .../imap/response/imap-fetch-data-decoder.vala     | 28 ++++++++++++++++------
 src/engine/imap/response/imap-fetched-data.vala    |  2 +-
 test/meson.build                                   |  1 +
 test/test-engine.vala                              |  1 +
 7 files changed, 57 insertions(+), 10 deletions(-)
---
diff --git a/src/engine/imap/api/imap-quirks.vala b/src/engine/imap/api/imap-quirks.vala
index 79ef32673..9a163edf0 100644
--- a/src/engine/imap/api/imap-quirks.vala
+++ b/src/engine/imap/api/imap-quirks.vala
@@ -38,5 +38,25 @@ public class Geary.Imap.Quirks : BaseObject {
      */
     public uint max_pipeline_batch_size { get; set; default = 0; }
 
+    /**
+     * The value sent by the server for missing envelope mailbox local parts.
+     *
+     * IMAP FETCH ENVELOPE structures use NIL for the "mailbox name"
+     * part (in addition to a NIL "host name" part) as an end-of-list
+     * marker for RFC822 group syntax. To indicate a missing
+     * local-part in a non-group mailbox some mail servers use a
+     * string such as "MISSING_MAILBOX" rather than the empty string.
+     */
+    public string empty_envelope_mailbox_name { get; set; default = ""; }
+
+    /**
+     * The value sent by the server for missing envelope mailbox domains.
+     *
+     * IMAP FETCH ENVELOPE structures use NIL for the "host name"
+     * argument to indicate RFC822 group syntax. To indicate a missing
+     * some mail servers use a string such as "MISSING_DOMAIN" rather
+     * than the empty string.
+     */
+    public string empty_envelope_host_name { get; set; default = ""; }
 
 }
diff --git a/src/engine/imap/message/imap-fetch-data-specifier.vala 
b/src/engine/imap/message/imap-fetch-data-specifier.vala
index 5d05c6744..7f60acc79 100644
--- a/src/engine/imap/message/imap-fetch-data-specifier.vala
+++ b/src/engine/imap/message/imap-fetch-data-specifier.vala
@@ -142,7 +142,7 @@ public enum Geary.Imap.FetchDataSpecifier {
      *
      * @return null if no FetchDataDecoder is associated with this value, or an invalid value.
      */
-    public FetchDataDecoder? get_decoder() {
+    public FetchDataDecoder? get_decoder(Quirks quirks) {
         switch (this) {
             case UID:
                 return new UIDDecoder();
@@ -151,7 +151,7 @@ public enum Geary.Imap.FetchDataSpecifier {
                 return new MessageFlagsDecoder();
 
             case ENVELOPE:
-                return new EnvelopeDecoder();
+                return new EnvelopeDecoder(quirks);
 
             case INTERNALDATE:
                 return new InternalDateDecoder();
diff --git a/src/engine/imap/parameter/imap-list-parameter.vala 
b/src/engine/imap/parameter/imap-list-parameter.vala
index d580830a0..777d42fc5 100644
--- a/src/engine/imap/parameter/imap-list-parameter.vala
+++ b/src/engine/imap/parameter/imap-list-parameter.vala
@@ -29,6 +29,17 @@ public class Geary.Imap.ListParameter : Geary.Imap.Parameter {
     private Gee.List<Parameter> list = new Gee.ArrayList<Parameter>();
 
 
+    /** Constructs a new, empty list. */
+    public ListParameter() {
+        // noop
+    }
+
+    /** Constructs a new list wit a single parameter. */
+    public ListParameter.single(Parameter param) {
+        base();
+        add(param);
+    }
+
     /**
      * Appends a parameter to the end of this list.
      *
diff --git a/src/engine/imap/response/imap-fetch-data-decoder.vala 
b/src/engine/imap/response/imap-fetch-data-decoder.vala
index 1c35d99ae..4701a1dac 100644
--- a/src/engine/imap/response/imap-fetch-data-decoder.vala
+++ b/src/engine/imap/response/imap-fetch-data-decoder.vala
@@ -124,8 +124,14 @@ public class Geary.Imap.RFC822SizeDecoder : Geary.Imap.FetchDataDecoder {
 }
 
 public class Geary.Imap.EnvelopeDecoder : Geary.Imap.FetchDataDecoder {
-    public EnvelopeDecoder() {
-        base (FetchDataSpecifier.ENVELOPE);
+
+
+    private Quirks quirks;
+
+
+    public EnvelopeDecoder(Quirks quirks) {
+        base(FetchDataSpecifier.ENVELOPE);
+        this.quirks = quirks;
     }
 
     protected override MessageData decode_list(ListParameter listp) throws ImapError {
@@ -150,7 +156,7 @@ public class Geary.Imap.EnvelopeDecoder : Geary.Imap.FetchDataDecoder {
             try {
                 sent_date = new RFC822.Date.from_rfc822_string(sent.ascii);
             } catch (GLib.Error err) {
-                debug(
+                warning(
                     "Error parsing sent date from FETCH envelope: %s",
                     err.message
                 );
@@ -179,14 +185,22 @@ public class Geary.Imap.EnvelopeDecoder : Geary.Imap.FetchDataDecoder {
             ListParameter fields = listp.get_as_empty_list(ctr);
             StringParameter? name = fields.get_as_nullable_string(0);
             StringParameter? source_route = fields.get_as_nullable_string(1);
-            StringParameter mailbox = fields.get_as_empty_string(2);
-            StringParameter domain = fields.get_as_empty_string(3);
+            StringParameter? mailbox = fields.get_as_empty_string(2);
+            StringParameter? domain = fields.get_as_empty_string(3);
+
+            if (mailbox.ascii == this.quirks.empty_envelope_mailbox_name) {
+                mailbox = null;
+            }
+            if (domain.ascii == this.quirks.empty_envelope_host_name) {
+                domain = null;
+            }
 
             Geary.RFC822.MailboxAddress addr = new Geary.RFC822.MailboxAddress.imap(
                 (name != null) ? name.nullable_ascii : null,
                 (source_route != null) ? source_route.nullable_ascii : null,
-                mailbox.ascii,
-                domain.ascii);
+                mailbox != null ? mailbox.ascii : "",
+                domain != null ? domain.ascii : ""
+            );
             list.add(addr);
         }
 
diff --git a/src/engine/imap/response/imap-fetched-data.vala b/src/engine/imap/response/imap-fetched-data.vala
index 7bc47d576..7f3773968 100644
--- a/src/engine/imap/response/imap-fetched-data.vala
+++ b/src/engine/imap/response/imap-fetched-data.vala
@@ -73,7 +73,7 @@ public class Geary.Imap.FetchedData : Object {
                     fetched_data.body_data_map.set(specifier, Memory.EmptyBuffer.instance);
             } else {
                 FetchDataSpecifier data_item = FetchDataSpecifier.from_parameter(data_item_param);
-                FetchDataDecoder? decoder = data_item.get_decoder();
+                FetchDataDecoder? decoder = data_item.get_decoder(server_data.quirks);
                 if (decoder == null) {
                     debug("Unable to decode fetch response for \"%s\": No decoder available",
                         data_item.to_string());
diff --git a/test/meson.build b/test/meson.build
index a2fc8a624..6ea5e27aa 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -43,6 +43,7 @@ test_engine_sources = [
   'engine/imap/message/imap-data-format-test.vala',
   'engine/imap/message/imap-mailbox-specifier-test.vala',
   'engine/imap/parameter/imap-list-parameter-test.vala',
+  'engine/imap/response/imap-fetch-data-decoder-test.vala',
   'engine/imap/response/imap-namespace-response-test.vala',
   'engine/imap/transport/imap-client-connection-test.vala',
   'engine/imap/transport/imap-client-session-test.vala',
diff --git a/test/test-engine.vala b/test/test-engine.vala
index 483163deb..0260ef6a8 100644
--- a/test/test-engine.vala
+++ b/test/test-engine.vala
@@ -56,6 +56,7 @@ int main(string[] args) {
 
     engine.add_suite(new Geary.Imap.CreateCommandTest().suite);
     engine.add_suite(new Geary.Imap.FetchCommandTest().suite);
+    engine.add_suite(new Geary.Imap.FetchDataDecoderTest().suite);
     engine.add_suite(new Geary.Imap.ListParameterTest().suite);
     engine.add_suite(new Geary.Imap.MailboxSpecifierTest().suite);
     engine.add_suite(new Geary.Imap.NamespaceResponseTest().suite);