feat: Add hover docs for builtin types: (#42)

Adds hover docs to builtin types such as `int`, `string` etc in message
fields and methods.

src/lsp.rs

@@ -163,7 +163,7 @@ impl LanguageServer for ProtoLanguageServer {
         };
 
         let content = self.state.get_content(&uri);
-        let identifier = tree.get_actionable_node_text_at_position(&pos, content.as_bytes());
+        let identifier = tree.get_hoverable_node_text_at_position(&pos, content.as_bytes());
         let current_package_name = tree.get_package_name(content.as_bytes());
 
         let Some(identifier) = identifier else {

src/parser/tree.rs

@@ -63,6 +63,16 @@ impl ParsedTree {
             .map(|n| n.utf8_text(content.as_ref()).expect("utf-8 parse error"))
     }
 
+    pub fn get_hoverable_node_text_at_position<'a>(
+        &'a self,
+        pos: &Position,
+        content: &'a [u8],
+    ) -> Option<&'a str> {
+        let n = self.get_node_at_position(pos)?;
+        self.get_actionable_node_text_at_position(pos, content)
+            .or(Some(n.kind()))
+    }
+
     pub fn get_ancestor_nodes_at_position<'a>(&'a self, pos: &Position) -> Vec<Node<'a>> {
         let Some(mut n) = self.get_actionable_node_at_position(pos) else {
             return vec![];

src/workspace/hover.rs

@@ -1,11 +1,118 @@
+use std::{collections::HashMap, sync::LazyLock};
+
 use async_lsp::lsp_types::MarkedString;
 
 use crate::{
     formatter::ProtoFormatter, state::ProtoLanguageState, utils::split_identifier_package,
 };
 
+
+static BUITIN_DOCS: LazyLock<HashMap<&'static str, &'static str>> = LazyLock::new(|| {
+    HashMap::from([
+        (
+            "int32",
+            r#"A 32-bit integer (varint encoding)
+
+Values of this type range between `-2147483648` and `2147483647`.
+Beware that negative values are encoded as five bytes on the wire!"#,
+        ),
+        (
+            "int64",
+            r#"A 64-bit integer (varint encoding)
+
+Values of this type range between `-9223372036854775808` and `9223372036854775807`.
+Beware that negative values are encoded as ten bytes on the wire!"#,
+        ),
+        (
+            "uint32",
+            r#"A 32-bit unsigned integer (varint encoding)
+
+Values of this type range between `0` and `4294967295`."#,
+        ),
+        (
+            "uint64",
+            r#"A 64-bit unsigned integer (varint encoding)
+
+Values of this type range between `0` and `18446744073709551615`."#,
+        ),
+        (
+            "sint32",
+            r#"A 32-bit integer (ZigZag encoding)
+
+Values of this type range between `-2147483648` and `2147483647`."#,
+        ),
+        (
+            "sint64",
+            r#"A 64-bit integer (ZigZag encoding)
+
+Values of this type range between `-9223372036854775808` and `9223372036854775807`."#,
+        ),
+        (
+            "fixed32",
+            r#"A 32-bit unsigned integer (4-byte encoding)
+
+Values of this type range between `0` and `4294967295`."#,
+        ),
+        (
+            "fixed64",
+            r#"A 64-bit unsigned integer (8-byte encoding)
+
+Values of this type range between `0` and `18446744073709551615`."#,
+        ),
+        (
+            "sfixed32",
+            r#"A 32-bit integer (4-byte encoding)
+
+Values of this type range between `-2147483648` and `2147483647`."#,
+        ),
+        (
+            "sfixed64",
+            r#"A 64-bit integer (8-byte encoding)
+
+Values of this type range between `-9223372036854775808` and `9223372036854775807`."#,
+        ),
+        (
+            "float",
+            "A single-precision floating point number (IEEE-745.2008 binary32).",
+        ),
+        (
+            "double",
+            "A double-precision floating point number (IEEE-745.2008 binary64).",
+        ),
+        (
+            "string",
+            r#"A string of text.
+
+Stores at most 4GB of text. Intended to be UTF-8 encoded Unicode; use `bytes` if you need other encodings."#,
+        ),
+        (
+            "bytes",
+            r#"A blob of arbitrary bytes.
+
+Stores at most 4GB of binary data. Encoded as base64 in JSON."#,
+        ),
+        (
+            "bool",
+            r#"A Boolean value: `true` or `false`.
+
+Encoded as a single byte: `0x00` or `0xff` (all non-zero bytes decode to `true`)."#,
+        ),
+        (
+            "default",
+            r#"A magic option that specifies the field's default value.
+
+Unlike every other option on a field, this does not have a corresponding field in
+`google.protobuf.FieldOptions`; it is implemented by compiler magic."#,
+        ),
+    ])
+});
+
 impl<F: ProtoFormatter> ProtoLanguageState<F> {
     pub fn hover(&self, curr_package: &str, identifier: &str) -> Vec<MarkedString> {
+        if let Some(docs) = BUITIN_DOCS.get(identifier) {
+            return vec![MarkedString::String(docs.to_string())];
+        }
+
         let (mut package, identifier) = split_identifier_package(identifier);
         if package.is_empty() {
             package = curr_package;
@@ -42,6 +149,7 @@ mod test {
         state.upsert_file(&c_uri, c.to_owned());
 
         assert_yaml_snapshot!(state.hover("com.workspace", "Author"));
+        assert_yaml_snapshot!(state.hover("com.workspace", "int64"));
         assert_yaml_snapshot!(state.hover("com.workspace", "Author.Address"));
         assert_yaml_snapshot!(state.hover("com.workspace", "com.utility.Foobar.Baz"));
         assert_yaml_snapshot!(state.hover("com.utility", "Baz"));

src/workspace/snapshots/protols__workspace__hover__test__workspace_test_hover-2.snap

@@ -1,5 +1,6 @@
 ---
 source: src/workspace/hover.rs
-expression: "state.hover(\"com.library\", \"Author.Address\")"
+expression: "state.hover(\"com.workspace\", \"int64\")"
+snapshot_kind: text
 ---
-- Address is a Address
+- "A 64-bit integer (varint encoding)\n\nValues of this type range between `-9223372036854775808` and `9223372036854775807`.\nBeware that negative values are encoded as ten bytes on the wire!"

src/workspace/snapshots/protols__workspace__hover__test__workspace_test_hover-3.snap

@@ -1,5 +1,6 @@
 ---
 source: src/workspace/hover.rs
-expression: "state.hover(\"com.library\", \"com.utility.Foobar.Baz\")"
+expression: "state.hover(\"com.workspace\", \"Author.Address\")"
+snapshot_kind: text
 ---
-- What is baz?
+- Address is a Address

src/workspace/snapshots/protols__workspace__hover__test__workspace_test_hover-5.snap

@@ -0,0 +1,6 @@
+---
+source: src/workspace/hover.rs
+expression: "state.hover(\"com.utility\", \"Baz\")"
+snapshot_kind: text
+---
+- What is baz?