Some idle CPU and disk/io fixes, new CommandChanged plugin Event (#5063)

* initial implementation

* fix mouse cpu spam

* prevent excess metadata write and prune sessions on startup

* consolidate CommandChanged and PaneCommandChanged

* tests

* rustfmt

* add pr

4 files changed, 150 insertions, 10 deletions

diff --git a/zellij-utils/src/plugin_api/event.proto b/zellij-utils/src/plugin_api/event.proto
index ce9eb8ff..3c3a8490 100644
--- a/zellij-utils/src/plugin_api/event.proto
+++ b/zellij-utils/src/plugin_api/event.proto
@@ -67,6 +67,7 @@ enum EventType {
     HighlightClicked = 42;
     PaneRenderReportWithAnsi = 43;
     InitialKeybinds = 44;
+    CommandChanged = 45;
 }
 
 message EventNameList {
@@ -113,6 +114,7 @@ message Event {
     HighlightClickedPayload highlight_clicked_payload = 36;
     PaneRenderReportPayload pane_render_report_with_ansi_payload = 37;
     InitialKeybindsPayload initial_keybinds_payload = 38;
+    CommandChangedPayload command_changed_payload = 39;
   }
 }
 
@@ -122,6 +124,13 @@ message CwdChangedPayload {
   repeated uint32 focused_client_ids = 3;
 }
 
+message CommandChangedPayload {
+  PaneId pane_id = 1;
+  repeated string command = 2;
+  bool is_foreground = 3;
+  repeated uint32 focused_client_ids = 4;
+}
+
 message FailedToStartWebServerPayload {
   string error = 1;
 }
diff --git a/zellij-utils/src/plugin_api/event.rs b/zellij-utils/src/plugin_api/event.rs
index 93b28365..6f138742 100644
--- a/zellij-utils/src/plugin_api/event.rs
+++ b/zellij-utils/src/plugin_api/event.rs
@@ -6,7 +6,8 @@ pub use super::generated_api::api::{
         pane_scrollback_response, ActionCompletePayload as ProtobufActionCompletePayload,
         AvailableLayoutInfoPayload as ProtobufAvailableLayoutInfoPayload,
         ClientInfo as ProtobufClientInfo, ClientPaneHistory as ProtobufClientPaneHistory,
-        ClientTabHistory as ProtobufClientTabHistory, ContextItem as ProtobufContextItem,
+        ClientTabHistory as ProtobufClientTabHistory,
+        CommandChangedPayload as ProtobufCommandChangedPayload, ContextItem as ProtobufContextItem,
         CopyDestination as ProtobufCopyDestination, CwdChangedPayload as ProtobufCwdChangedPayload,
         Event as ProtobufEvent, EventNameList as ProtobufEventNameList,
         EventType as ProtobufEventType, FileMetadata as ProtobufFileMetadata,
@@ -474,6 +475,27 @@ impl TryFrom<ProtobufEvent> for Event {
                 },
                 _ => Err("Malformed payload for the CwdChanged Event"),
             },
+            Some(ProtobufEventType::CommandChanged) => match protobuf_event.payload {
+                Some(ProtobufEventPayload::CommandChangedPayload(p)) => {
+                    let pane_id: PaneId = p
+                        .pane_id
+                        .ok_or("Missing pane_id in CommandChanged payload")?
+                        .try_into()
+                        .map_err(|_| "Failed to convert PaneId in CommandChanged payload")?;
+                    let focused_client_ids: Vec<ClientId> = p
+                        .focused_client_ids
+                        .into_iter()
+                        .map(|id| id as u16)
+                        .collect();
+                    Ok(Event::CommandChanged(
+                        pane_id,
+                        p.command,
+                        p.is_foreground,
+                        focused_client_ids,
+                    ))
+                },
+                _ => Err("Malformed payload for the CommandChanged Event"),
+            },
             Some(ProtobufEventType::AvailableLayoutInfo) => match protobuf_event.payload {
                 Some(ProtobufEventPayload::AvailableLayoutInfoPayload(
                     available_layout_info_payload,
@@ -1014,6 +1036,21 @@ impl TryFrom<Event> for ProtobufEvent {
                     payload: Some(event::Payload::CwdChangedPayload(cwd_changed_payload)),
                 })
             },
+            Event::CommandChanged(pane_id, command, is_foreground, focused_client_ids) => {
+                let protobuf_pane_id: ProtobufPaneId = pane_id.try_into()?;
+                let focused_client_ids_u32: Vec<u32> =
+                    focused_client_ids.into_iter().map(|id| id as u32).collect();
+                let payload = ProtobufCommandChangedPayload {
+                    pane_id: Some(protobuf_pane_id),
+                    command,
+                    is_foreground,
+                    focused_client_ids: focused_client_ids_u32,
+                };
+                Ok(ProtobufEvent {
+                    name: ProtobufEventType::CommandChanged as i32,
+                    payload: Some(event::Payload::CommandChangedPayload(payload)),
+                })
+            },
             Event::AvailableLayoutInfo(available_layouts, layouts_with_errors) => {
                 let mut protobuf_available_layouts = vec![];
                 let mut protobuf_layouts_with_errors = vec![];
@@ -2015,6 +2052,7 @@ impl TryFrom<ProtobufEventType> for EventType {
             ProtobufEventType::UserAction => EventType::UserAction,
             ProtobufEventType::ActionComplete => EventType::ActionComplete,
             ProtobufEventType::CwdChanged => EventType::CwdChanged,
+            ProtobufEventType::CommandChanged => EventType::CommandChanged,
             ProtobufEventType::AvailableLayoutInfo => EventType::AvailableLayoutInfo,
             ProtobufEventType::PluginConfigurationChanged => EventType::PluginConfigurationChanged,
             ProtobufEventType::HighlightClicked => EventType::HighlightClicked,
@@ -2067,6 +2105,7 @@ impl TryFrom<EventType> for ProtobufEventType {
             EventType::UserAction => ProtobufEventType::UserAction,
             EventType::ActionComplete => ProtobufEventType::ActionComplete,
             EventType::CwdChanged => ProtobufEventType::CwdChanged,
+            EventType::CommandChanged => ProtobufEventType::CommandChanged,
             EventType::AvailableLayoutInfo => ProtobufEventType::AvailableLayoutInfo,
             EventType::PluginConfigurationChanged => ProtobufEventType::PluginConfigurationChanged,
             EventType::HighlightClicked => ProtobufEventType::HighlightClicked,
diff --git a/zellij-utils/src/plugin_api/plugin_command.proto b/zellij-utils/src/plugin_api/plugin_command.proto
index 63baa443..0b768838 100644
--- a/zellij-utils/src/plugin_api/plugin_command.proto
+++ b/zellij-utils/src/plugin_api/plugin_command.proto
@@ -203,6 +203,7 @@ enum CommandName {
   ClearPaneHighlights = 208;
   OpenPluginPaneFloating = 209;
   ListWindowsVolumes = 210;
+  GetSessionList = 211;
 }
 
 message PluginCommand {
@@ -354,6 +355,7 @@ message PluginCommand {
     SetPaneRegexHighlightsPayload set_pane_regex_highlights_payload = 158;
     ClearPaneHighlightsPayload clear_pane_highlights_payload = 159;
     OpenPluginPaneFloatingPayload open_plugin_pane_floating_payload = 160;
+    GetSessionListPayload get_session_list_payload = 161;
   }
 }
 
@@ -1295,3 +1297,17 @@ message OpenPluginPaneFloatingPayload {
 message OpenPluginPaneFloatingResponse {
   optional PaneId pane_id = 1;
 }
+
+message GetSessionListPayload {}
+
+message SessionListSnapshot {
+  repeated event.SessionManifest live_sessions = 1;
+  repeated event.ResurrectableSession resurrectable_sessions = 2;
+}
+
+message GetSessionListResponse {
+  oneof result {
+    SessionListSnapshot snapshot = 1;
+    string error = 2;
+  }
+}
diff --git a/zellij-utils/src/plugin_api/plugin_command.rs b/zellij-utils/src/plugin_api/plugin_command.rs
index a457f720..5bfb2b42 100644
--- a/zellij-utils/src/plugin_api/plugin_command.rs
+++ b/zellij-utils/src/plugin_api/plugin_command.rs
@@ -1,13 +1,17 @@
 pub use super::generated_api::api::{
     action::{Action as ProtobufAction, PaneIdAndShouldFloat, SwitchToModePayload},
-    event::{EventNameList as ProtobufEventNameList, Header},
+    event::{
+        EventNameList as ProtobufEventNameList, Header,
+        ResurrectableSession as ProtobufResurrectableSession,
+        SessionManifest as ProtobufSessionManifest,
+    },
     input_mode::InputMode as ProtobufInputMode,
     plugin_command::{
         break_panes_to_new_tab_response, break_panes_to_tab_with_id_response,
         break_panes_to_tab_with_index_response, delete_layout_response, dump_layout_response,
         dump_session_layout_response, edit_layout_response, focus_or_create_tab_response,
         get_focused_pane_info_response, get_pane_cwd_response, get_pane_pid_response,
-        get_pane_running_command_response, hide_floating_panes_response,
+        get_pane_running_command_response, get_session_list_response, hide_floating_panes_response,
         highlight_style::Style as ProtobufHighlightStyleVariant, new_tab_response,
         parse_layout_response, plugin_command::Payload, rename_layout_response,
         save_layout_response, save_session_response, show_floating_panes_response,
@@ -48,7 +52,9 @@ pub use super::generated_api::api::{
         GetPaneScrollbackPayload,
         GetSessionEnvironmentVariablesPayload as ProtobufGetSessionEnvironmentVariablesPayload,
         GetSessionEnvironmentVariablesResponse as ProtobufGetSessionEnvironmentVariablesResponse,
-        GetTabInfoPayload, GetTabInfoResponse as ProtobufGetTabInfoResponse, GoToTabWithIdPayload,
+        GetSessionListPayload as ProtobufGetSessionListPayload,
+        GetSessionListResponse as ProtobufGetSessionListResponse, GetTabInfoPayload,
+        GetTabInfoResponse as ProtobufGetTabInfoResponse, GoToTabWithIdPayload,
         GroupAndUngroupPanesPayload, HideFloatingPanesPayload as ProtobufHideFloatingPanesPayload,
         HideFloatingPanesResponse as ProtobufHideFloatingPanesResponse, HidePaneWithIdPayload,
         HighlightAndUnhighlightPanesPayload, HighlightLayer as ProtobufHighlightLayer,
@@ -108,9 +114,10 @@ pub use super::generated_api::api::{
         SaveLayoutPayload, SaveLayoutResponse as ProtobufSaveLayoutResponse, SaveSessionPayload,
         SaveSessionResponse as ProtobufSaveSessionResponse, ScrollDownInPaneIdPayload,
         ScrollToBottomInPaneIdPayload, ScrollToTopInPaneIdPayload, ScrollUpInPaneIdPayload,
-        SetFloatingPanePinnedPayload, SetPaneBorderlessPayload, SetPaneColorPayload,
-        SetPaneRegexHighlightsPayload, SetSelfMouseSelectionSupportPayload, SetTimeoutPayload,
-        ShowCursorPayload, ShowFloatingPanesPayload as ProtobufShowFloatingPanesPayload,
+        SessionListSnapshot as ProtobufSessionListSnapshot, SetFloatingPanePinnedPayload,
+        SetPaneBorderlessPayload, SetPaneColorPayload, SetPaneRegexHighlightsPayload,
+        SetSelfMouseSelectionSupportPayload, SetTimeoutPayload, ShowCursorPayload,
+        ShowFloatingPanesPayload as ProtobufShowFloatingPanesPayload,
         ShowFloatingPanesResponse as ProtobufShowFloatingPanesResponse, ShowPaneWithIdPayload,
         StackPanesPayload, SubscribePayload, SwitchSessionPayload, SwitchTabToIdPayload,
         SwitchTabToPayload, TogglePaneBorderlessPayload, TogglePaneEmbedOrEjectForPaneIdPayload,
@@ -124,9 +131,10 @@ pub use super::generated_api::api::{
 use crate::data::{
     ConnectToSession, DeleteLayoutResponse, EditLayoutResponse, FloatingPaneCoordinates,
     GetFocusedPaneInfoResponse, GetPaneCwdResponse, GetPanePidResponse,
-    GetPaneRunningCommandResponse, HighlightLayer, HighlightStyle, HttpVerb, InputMode,
-    KeyWithModifier, MessageToPlugin, NewPluginArgs, PaneId, PermissionType, PluginCommand,
-    RegexHighlight, RenameLayoutResponse, SaveLayoutResponse,
+    GetPaneRunningCommandResponse, GetSessionListResponse, HighlightLayer, HighlightStyle,
+    HttpVerb, InputMode, KeyWithModifier, MessageToPlugin, NewPluginArgs, PaneId, PermissionType,
+    PluginCommand, RegexHighlight, RenameLayoutResponse, SaveLayoutResponse, SessionInfo,
+    SessionListSnapshot,
 };
 use crate::input::actions::Action;
 use crate::input::layout::PercentOrFixed;
@@ -329,6 +337,63 @@ impl From<GetPaneRunningCommandResponse> for ProtobufGetPaneRunningCommandRespon
     }
 }
 
+impl From<GetSessionListResponse> for ProtobufGetSessionListResponse {
+    fn from(response: GetSessionListResponse) -> Self {
+        match response {
+            GetSessionListResponse::Ok(snapshot) => {
+                let live_sessions = snapshot
+                    .live_sessions
+                    .into_iter()
+                    .filter_map(|si| ProtobufSessionManifest::try_from(si).ok())
+                    .collect();
+                let resurrectable_sessions = snapshot
+                    .resurrectable_sessions
+                    .into_iter()
+                    .map(|entry| ProtobufResurrectableSession::from(entry))
+                    .collect();
+                ProtobufGetSessionListResponse {
+                    result: Some(get_session_list_response::Result::Snapshot(
+                        ProtobufSessionListSnapshot {
+                            live_sessions,
+                            resurrectable_sessions,
+                        },
+                    )),
+                }
+            },
+            GetSessionListResponse::Err(err) => ProtobufGetSessionListResponse {
+                result: Some(get_session_list_response::Result::Error(err)),
+            },
+        }
+    }
+}
+
+impl TryFrom<ProtobufGetSessionListResponse> for GetSessionListResponse {
+    type Error = &'static str;
+    fn try_from(protobuf_response: ProtobufGetSessionListResponse) -> Result<Self, &'static str> {
+        match protobuf_response.result {
+            Some(get_session_list_response::Result::Snapshot(snapshot)) => {
+                let mut live_sessions: Vec<SessionInfo> = Vec::new();
+                for manifest in snapshot.live_sessions {
+                    live_sessions.push(SessionInfo::try_from(manifest)?);
+                }
+                let resurrectable_sessions = snapshot
+                    .resurrectable_sessions
+                    .into_iter()
+                    .map(<(String, std::time::Duration)>::from)
+                    .collect();
+                Ok(GetSessionListResponse::Ok(SessionListSnapshot {
+                    live_sessions,
+                    resurrectable_sessions,
+                }))
+            },
+            Some(get_session_list_response::Result::Error(err)) => {
+                Ok(GetSessionListResponse::Err(err))
+            },
+            None => Err("Empty GetSessionListResponse"),
+        }
+    }
+}
+
 impl From<GetPaneCwdResponse> for ProtobufGetPaneCwdResponse {
     fn from(response: GetPaneCwdResponse) -> Self {
         match response {
@@ -1300,6 +1365,11 @@ impl TryFrom<ProtobufPluginCommand> for PluginCommand {
                 Some(_) => Err("ListWindowsVolumes should have no payload"),
                 None => Ok(PluginCommand::ListWindowsVolumes),
             },
+            Some(CommandName::GetSessionList) => match protobuf_plugin_command.payload {
+                Some(Payload::GetSessionListPayload(_)) => Ok(PluginCommand::GetSessionList),
+                None => Ok(PluginCommand::GetSessionList),
+                _ => Err("Mismatched payload for GetSessionList"),
+            },
             Some(CommandName::DumpSessionLayout) => match protobuf_plugin_command.payload {
                 Some(Payload::DumpSessionLayoutPayload(payload)) => {
                     Ok(PluginCommand::DumpSessionLayout {
@@ -3145,6 +3215,12 @@ impl TryFrom<PluginCommand> for ProtobufPluginCommand {
                 name: CommandName::ListWindowsVolumes as i32,
                 payload: None,
             }),
+            PluginCommand::GetSessionList => Ok(ProtobufPluginCommand {
+                name: CommandName::GetSessionList as i32,
+                payload: Some(Payload::GetSessionListPayload(
+                    ProtobufGetSessionListPayload {},
+                )),
+            }),
             PluginCommand::DumpSessionLayout { tab_index } => Ok(ProtobufPluginCommand {
                 name: CommandName::DumpSessionLayout as i32,
                 payload: tab_index.map(|idx| {