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, 71 insertions, 0 deletions

diff --git a/zellij-utils/src/plugin_api/pipe_message.rs b/zellij-utils/src/plugin_api/pipe_message.rs
new file mode 100644
index 00000000..dbfe4930
--- /dev/null
+++ b/zellij-utils/src/plugin_api/pipe_message.rs
@@ -0,0 +1,71 @@
+pub use super::generated_api::api::pipe_message::{
+    Arg as ProtobufArg, PipeMessage as ProtobufPipeMessage, PipeSource as ProtobufPipeSource,
+};
+use crate::data::{PipeMessage, PipeSource};
+
+use std::convert::TryFrom;
+
+impl TryFrom<ProtobufPipeMessage> for PipeMessage {
+    type Error = &'static str;
+    fn try_from(protobuf_pipe_message: ProtobufPipeMessage) -> Result<Self, &'static str> {
+        let source = match (
+            ProtobufPipeSource::from_i32(protobuf_pipe_message.source),
+            protobuf_pipe_message.cli_source_id,
+            protobuf_pipe_message.plugin_source_id,
+        ) {
+            (Some(ProtobufPipeSource::Cli), Some(cli_source_id), _) => {
+                PipeSource::Cli(cli_source_id)
+            },
+            (Some(ProtobufPipeSource::Plugin), _, Some(plugin_source_id)) => {
+                PipeSource::Plugin(plugin_source_id)
+            },
+            _ => return Err("Invalid PipeSource or payload"),
+        };
+        let name = protobuf_pipe_message.name;
+        let payload = protobuf_pipe_message.payload;
+        let args = protobuf_pipe_message
+            .args
+            .into_iter()
+            .map(|arg| (arg.key, arg.value))
+            .collect();
+        let is_private = protobuf_pipe_message.is_private;
+        Ok(PipeMessage {
+            source,
+            name,
+            payload,
+            args,
+            is_private,
+        })
+    }
+}
+
+impl TryFrom<PipeMessage> for ProtobufPipeMessage {
+    type Error = &'static str;
+    fn try_from(pipe_message: PipeMessage) -> Result<Self, &'static str> {
+        let (source, cli_source_id, plugin_source_id) = match pipe_message.source {
+            PipeSource::Cli(input_pipe_id) => {
+                (ProtobufPipeSource::Cli as i32, Some(input_pipe_id), None)
+            },
+            PipeSource::Plugin(plugin_id) => {
+                (ProtobufPipeSource::Plugin as i32, None, Some(plugin_id))
+            },
+        };
+        let name = pipe_message.name;
+        let payload = pipe_message.payload;
+        let args: Vec<_> = pipe_message
+            .args
+            .into_iter()
+            .map(|(key, value)| ProtobufArg { key, value })
+            .collect();
+        let is_private = pipe_message.is_private;
+        Ok(ProtobufPipeMessage {
+            source,
+            cli_source_id,
+            plugin_source_id,
+            name,
+            payload,
+            args,
+            is_private,
+        })
+    }
+}