feat(plugins): introduce 'pipes', allowing users to pipe data to and control plugins from the command line (#3066)

* prototype - working with message from the cli

* prototype - pipe from the CLI to plugins

* prototype - pipe from the CLI to plugins and back again

* prototype - working with better cli interface

* prototype - working after removing unused stuff

* prototype - working with launching plugin if it is not launched, also fixed event ordering

* refactor: change message to cli-message

* prototype - allow plugins to send messages to each other

* fix: allow cli messages to send plugin parameters (and implement backpressure)

* fix: use input_pipe_id to identify cli pipes instead of their message name

* fix: come cleanups and add skip_cache parameter

* fix: pipe/client-server communication robustness

* fix: leaking messages between plugins while loading

* feat: allow plugins to specify how a new plugin instance is launched when sending messages

* fix: add permissions

* refactor: adjust cli api

* fix: improve cli plugin loading error messages

* docs: cli pipe

* fix: take plugin configuration into account when messaging between plugins

* refactor: pipe message protobuf interface

* refactor: update(event) -> pipe

* refactor - rename CliMessage to CliPipe

* fix: add is_private to pipes and change some naming

* refactor - cli client

* refactor: various cleanups

* style(fmt): rustfmt

* fix(pipes): backpressure across multiple plugins

* style: some cleanups

* style(fmt): rustfmt

* style: fix merge conflict mistake

* style(wording): clarify pipe permission

1 files changed, 40 insertions, 0 deletions

diff --git a/zellij-utils/src/plugin_api/plugin_command.proto b/zellij-utils/src/plugin_api/plugin_command.proto
index 53994a88..6ffb0345 100644
--- a/zellij-utils/src/plugin_api/plugin_command.proto
+++ b/zellij-utils/src/plugin_api/plugin_command.proto
@@ -87,6 +87,10 @@ enum CommandName {
   DeleteDeadSession = 73;
   DeleteAllDeadSessions = 74;
   RenameSession = 75;
+  UnblockCliPipeInput = 76;
+  BlockCliPipeInput = 77;
+  CliPipeOutput = 78;
+  MessageToPlugin = 79;
 }
 
 message PluginCommand {
@@ -137,9 +141,45 @@ message PluginCommand {
     WebRequestPayload web_request_payload = 44;
     string delete_dead_session_payload = 45;
     string rename_session_payload = 46;
+    string unblock_cli_pipe_input_payload = 47;
+    string block_cli_pipe_input_payload = 48;
+    CliPipeOutputPayload cli_pipe_output_payload = 49;
+    MessageToPluginPayload message_to_plugin_payload = 50;
   }
 }
 
+message CliPipeOutputPayload {
+  string pipe_name = 1;
+  string output = 2;
+}
+
+message MessageToPluginPayload {
+  optional string plugin_url = 1;
+  repeated ContextItem plugin_config = 2;
+  string message_name = 3;
+  optional string message_payload = 4;
+  repeated ContextItem message_args = 5;
+  optional NewPluginArgs new_plugin_args = 6;
+}
+
+message NewPluginArgs {
+    optional bool should_float = 1;
+    optional PaneId pane_id_to_replace = 2;
+    optional string pane_title = 3;
+    optional string cwd = 4;
+    bool skip_cache = 5;
+}
+
+message PaneId {
+  PaneType pane_type = 1;
+  uint32 id = 2;
+}
+
+enum PaneType {
+  Terminal = 0;
+  Plugin = 1;
+}
+
 message SwitchSessionPayload {
   optional string name = 1;
   optional uint32 tab_position = 2;