From 46da80d726ace0e69e8a0993e01b682d0abc5725 Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Fri, 4 Mar 2022 10:11:10 +0100
Subject: [PATCH 1/2] Use LSP range formatting when document formatting is not
 available

---
 crates/project/src/project.rs | 44 ++++++++++++++++++++++++++++-------
 crates/text/src/rope.rs       |  4 ++++
 crates/text/src/text.rs       |  4 ++++
 3 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/crates/project/src/project.rs b/crates/project/src/project.rs
index a89317db90410d99c9d876b9206adace06ec8682..f207430d7ae104407552753528cbcf7aafcfe269 100644
--- a/crates/project/src/project.rs
+++ b/crates/project/src/project.rs
@@ -1314,15 +1314,41 @@ impl Project {
             }
 
             for (buffer, buffer_abs_path, lang_server) in local_buffers {
-                let lsp_edits = lang_server
-                    .request::<lsp::request::Formatting>(lsp::DocumentFormattingParams {
-                        text_document: lsp::TextDocumentIdentifier::new(
-                            lsp::Url::from_file_path(&buffer_abs_path).unwrap(),
-                        ),
-                        options: Default::default(),
-                        work_done_progress_params: Default::default(),
-                    })
-                    .await?;
+                let capabilities = if let Some(capabilities) = lang_server.capabilities().await {
+                    capabilities
+                } else {
+                    continue;
+                };
+
+                let text_document = lsp::TextDocumentIdentifier::new(
+                    lsp::Url::from_file_path(&buffer_abs_path).unwrap(),
+                );
+                let lsp_edits = if capabilities.document_formatting_provider.is_some() {
+                    lang_server
+                        .request::<lsp::request::Formatting>(lsp::DocumentFormattingParams {
+                            text_document,
+                            options: Default::default(),
+                            work_done_progress_params: Default::default(),
+                        })
+                        .await?
+                } else if capabilities.document_range_formatting_provider.is_some() {
+                    let buffer_start = lsp::Position::new(0, 0);
+                    let buffer_end = buffer
+                        .read_with(&cx, |buffer, _| buffer.max_point_utf16())
+                        .to_lsp_position();
+                    lang_server
+                        .request::<lsp::request::RangeFormatting>(
+                            lsp::DocumentRangeFormattingParams {
+                                text_document,
+                                range: lsp::Range::new(buffer_start, buffer_end),
+                                options: Default::default(),
+                                work_done_progress_params: Default::default(),
+                            },
+                        )
+                        .await?
+                } else {
+                    continue;
+                };
 
                 if let Some(lsp_edits) = lsp_edits {
                     let edits = buffer
diff --git a/crates/text/src/rope.rs b/crates/text/src/rope.rs
index 3d1cb28eb18bc0605a64cc40aa66b4618a2dcb2b..ce666968b2146f8a956029b139593fd4e0c1b2b9 100644
--- a/crates/text/src/rope.rs
+++ b/crates/text/src/rope.rs
@@ -126,6 +126,10 @@ impl Rope {
         self.chunks.extent(&())
     }
 
+    pub fn max_point_utf16(&self) -> PointUtf16 {
+        self.chunks.extent(&())
+    }
+
     pub fn cursor(&self, offset: usize) -> Cursor {
         Cursor::new(self, offset)
     }
diff --git a/crates/text/src/text.rs b/crates/text/src/text.rs
index 95441a12080c148afa07cfe0527b8db20b38ec06..89943777e06e4d21ef488a215c807064319e71a0 100644
--- a/crates/text/src/text.rs
+++ b/crates/text/src/text.rs
@@ -1526,6 +1526,10 @@ impl BufferSnapshot {
         self.visible_text.max_point()
     }
 
+    pub fn max_point_utf16(&self) -> PointUtf16 {
+        self.visible_text.max_point_utf16()
+    }
+
     pub fn point_to_offset(&self, point: Point) -> usize {
         self.visible_text.point_to_offset(point)
     }

From d8ef3a5d61ad581bcbe7f1d15db2fa4dd6c6688f Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Fri, 4 Mar 2022 11:24:18 +0100
Subject: [PATCH 2/2] Support formatting in fake LSP capabilities

---
 crates/lsp/src/lsp.rs         |  2 ++
 crates/project/src/project.rs | 10 ++++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/crates/lsp/src/lsp.rs b/crates/lsp/src/lsp.rs
index fce206830297baf1c256a7c87c86b2564529149b..5f3eb2caaffa9c055c8f038197beb41b0d105b73 100644
--- a/crates/lsp/src/lsp.rs
+++ b/crates/lsp/src/lsp.rs
@@ -524,6 +524,8 @@ impl LanguageServer {
         ServerCapabilities {
             document_highlight_provider: Some(OneOf::Left(true)),
             code_action_provider: Some(CodeActionProviderCapability::Simple(true)),
+            document_formatting_provider: Some(OneOf::Left(true)),
+            document_range_formatting_provider: Some(OneOf::Left(true)),
             ..Default::default()
         }
     }
diff --git a/crates/project/src/project.rs b/crates/project/src/project.rs
index f207430d7ae104407552753528cbcf7aafcfe269..53ca4bf3329c0ee8263499a54663558cb5ee95bc 100644
--- a/crates/project/src/project.rs
+++ b/crates/project/src/project.rs
@@ -1323,7 +1323,10 @@ impl Project {
                 let text_document = lsp::TextDocumentIdentifier::new(
                     lsp::Url::from_file_path(&buffer_abs_path).unwrap(),
                 );
-                let lsp_edits = if capabilities.document_formatting_provider.is_some() {
+                let lsp_edits = if capabilities
+                    .document_formatting_provider
+                    .map_or(false, |provider| provider != lsp::OneOf::Left(false))
+                {
                     lang_server
                         .request::<lsp::request::Formatting>(lsp::DocumentFormattingParams {
                             text_document,
@@ -1331,7 +1334,10 @@ impl Project {
                             work_done_progress_params: Default::default(),
                         })
                         .await?
-                } else if capabilities.document_range_formatting_provider.is_some() {
+                } else if capabilities
+                    .document_range_formatting_provider
+                    .map_or(false, |provider| provider != lsp::OneOf::Left(false))
+                {
                     let buffer_start = lsp::Position::new(0, 0);
                     let buffer_end = buffer
                         .read_with(&cx, |buffer, _| buffer.max_point_utf16())