Refactor to use new ACP crate (#35043)

This will prepare us for running the protocol over MCP

Release Notes:

- N/A

---------

Co-authored-by: Ben Brandt <benjamin.j.brandt@gmail.com>
Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>
Co-authored-by: Richard Feldman <oss@rtfeldman.com>

crates/agent_servers/src/gemini.rs

@@ -1,9 +1,17 @@
-use crate::stdio_agent_server::StdioAgentServer;
-use crate::{AgentServerCommand, AgentServerVersion};
+use anyhow::anyhow;
+use std::cell::RefCell;
+use std::path::Path;
+use std::rc::Rc;
+use util::ResultExt as _;
+
+use crate::{AgentServer, AgentServerCommand, AgentServerVersion};
+use acp_thread::{AgentConnection, LoadError, OldAcpAgentConnection, OldAcpClientDelegate};
+use agentic_coding_protocol as acp_old;
 use anyhow::{Context as _, Result};
-use gpui::{AsyncApp, Entity};
+use gpui::{AppContext as _, AsyncApp, Entity, Task, WeakEntity};
 use project::Project;
 use settings::SettingsStore;
+use ui::App;
 
 use crate::AllAgentServersSettings;
 
@@ -12,7 +20,7 @@ pub struct Gemini;
 
 const ACP_ARG: &str = "--experimental-acp";
 
-impl StdioAgentServer for Gemini {
+impl AgentServer for Gemini {
     fn name(&self) -> &'static str {
         "Gemini"
     }
@@ -25,14 +33,88 @@ impl StdioAgentServer for Gemini {
         "Ask questions, edit files, run commands.\nBe specific for the best results."
     }
 
-    fn supports_always_allow(&self) -> bool {
-        true
-    }
-
     fn logo(&self) -> ui::IconName {
         ui::IconName::AiGemini
     }
 
+    fn connect(
+        &self,
+        root_dir: &Path,
+        project: &Entity<Project>,
+        cx: &mut App,
+    ) -> Task<Result<Rc<dyn AgentConnection>>> {
+        let root_dir = root_dir.to_path_buf();
+        let project = project.clone();
+        let this = self.clone();
+        let name = self.name();
+
+        cx.spawn(async move |cx| {
+            let command = this.command(&project, cx).await?;
+
+            let mut child = util::command::new_smol_command(&command.path)
+                .args(command.args.iter())
+                .current_dir(root_dir)
+                .stdin(std::process::Stdio::piped())
+                .stdout(std::process::Stdio::piped())
+                .stderr(std::process::Stdio::inherit())
+                .kill_on_drop(true)
+                .spawn()?;
+
+            let stdin = child.stdin.take().unwrap();
+            let stdout = child.stdout.take().unwrap();
+
+            let foreground_executor = cx.foreground_executor().clone();
+
+            let thread_rc = Rc::new(RefCell::new(WeakEntity::new_invalid()));
+
+            let (connection, io_fut) = acp_old::AgentConnection::connect_to_agent(
+                OldAcpClientDelegate::new(thread_rc.clone(), cx.clone()),
+                stdin,
+                stdout,
+                move |fut| foreground_executor.spawn(fut).detach(),
+            );
+
+            let io_task = cx.background_spawn(async move {
+                io_fut.await.log_err();
+            });
+
+            let child_status = cx.background_spawn(async move {
+                let result = match child.status().await {
+                    Err(e) => Err(anyhow!(e)),
+                    Ok(result) if result.success() => Ok(()),
+                    Ok(result) => {
+                        if let Some(AgentServerVersion::Unsupported {
+                            error_message,
+                            upgrade_message,
+                            upgrade_command,
+                        }) = this.version(&command).await.log_err()
+                        {
+                            Err(anyhow!(LoadError::Unsupported {
+                                error_message,
+                                upgrade_message,
+                                upgrade_command
+                            }))
+                        } else {
+                            Err(anyhow!(LoadError::Exited(result.code().unwrap_or(-127))))
+                        }
+                    }
+                };
+                drop(io_task);
+                result
+            });
+
+            let connection: Rc<dyn AgentConnection> = Rc::new(OldAcpAgentConnection {
+                name,
+                connection,
+                child_status,
+            });
+
+            Ok(connection)
+        })
+    }
+}
+
+impl Gemini {
     async fn command(
         &self,
         project: &Entity<Project>,