Format source code (#1541)

We are importing `forge-fmt` for two reasons:
- This ensures that forge-fmt uses the latest solang-parser crate, and
we only have one version of solang-parser in solang binary
- This makes it possible to publish the solang crate to crates.io, since
forge-fmt is not on crates.io and no git depdendencies are allowed
- We requested feedback from Foundry on their discord server but
received no feedback

This feature is enabled with the help of
[forge-fmt](https://github.com/foundry-rs/foundry/tree/master/crates/fmt).

Cc: @gakonst @DaniPopes

Signed-off-by: Govardhan G D <[email protected]>

Cargo.toml

@@ -66,6 +66,7 @@ contract-build = { version = "3.0.1", optional = true }
 primitive-types = { version = "0.12", features = ["codec"] }
 normalize-path = "0.2.1"
 bitflags = "2.3.3"
+forge-fmt = "0.2.0"
 
 [dev-dependencies]
 num-derive = "0.4"

src/bin/languageserver/mod.rs

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: Apache-2.0
 
+use forge_fmt::{format, parse, FormatterConfig};
 use itertools::Itertools;
 use num_traits::ToPrimitive;
 use rust_lapper::{Interval, Lapper};
@@ -34,12 +35,12 @@ use tower_lsp::{
         DiagnosticRelatedInformation, DiagnosticSeverity, DidChangeConfigurationParams,
         DidChangeTextDocumentParams, DidChangeWatchedFilesParams, DidChangeWorkspaceFoldersParams,
         DidCloseTextDocumentParams, DidOpenTextDocumentParams, DidSaveTextDocumentParams,
-        ExecuteCommandOptions, ExecuteCommandParams, GotoDefinitionParams, GotoDefinitionResponse,
-        Hover, HoverContents, HoverParams, HoverProviderCapability,
-        ImplementationProviderCapability, InitializeParams, InitializeResult, InitializedParams,
-        Location, MarkedString, MessageType, OneOf, Position, Range, ReferenceParams, RenameParams,
-        ServerCapabilities, SignatureHelpOptions, TextDocumentContentChangeEvent,
-        TextDocumentSyncCapability, TextDocumentSyncKind, TextEdit,
+        DocumentFormattingParams, ExecuteCommandOptions, ExecuteCommandParams,
+        GotoDefinitionParams, GotoDefinitionResponse, Hover, HoverContents, HoverParams,
+        HoverProviderCapability, ImplementationProviderCapability, InitializeParams,
+        InitializeResult, InitializedParams, Location, MarkedString, MessageType, OneOf, Position,
+        Range, ReferenceParams, RenameParams, ServerCapabilities, SignatureHelpOptions,
+        TextDocumentContentChangeEvent, TextDocumentSyncCapability, TextDocumentSyncKind, TextEdit,
         TypeDefinitionProviderCapability, Url, WorkspaceEdit, WorkspaceFoldersServerCapabilities,
         WorkspaceServerCapabilities,
     },
@@ -1862,6 +1863,7 @@ impl LanguageServer for SolangServer {
                 declaration_provider: Some(DeclarationCapability::Simple(true)),
                 references_provider: Some(OneOf::Left(true)),
                 rename_provider: Some(OneOf::Left(true)),
+                document_formatting_provider: Some(OneOf::Left(true)),
                 ..ServerCapabilities::default()
             },
         })
@@ -2311,6 +2313,77 @@ impl LanguageServer for SolangServer {
 
         Ok(Some(WorkspaceEdit::new(ws)))
     }
+
+    /// Called when "Format Document" is called by the user on the client side.
+    ///
+    /// Expected to return the formatted version of source code present in the file on which this method was triggered.
+    ///
+    /// ### Arguments
+    /// * `DocumentFormattingParams`
+    ///     * provides the name of the file whose code is to be formatted.
+    ///     * provides options that help configure how the file is formatted.
+    ///
+    /// ### Edge cases
+    /// * Returns `Err` when
+    ///     * an invalid file path is received.
+    ///     * reading the file fails.
+    ///     * parsing the file fails.
+    ///     * formatting the file fails.
+    async fn formatting(&self, params: DocumentFormattingParams) -> Result<Option<Vec<TextEdit>>> {
+        // get parse tree for the input file
+        let uri = params.text_document.uri;
+        let source_path = uri.to_file_path().map_err(|_| Error {
+            code: ErrorCode::InvalidRequest,
+            message: format!("Received invalid URI: {uri}").into(),
+            data: None,
+        })?;
+        let source = std::fs::read_to_string(source_path).map_err(|err| Error {
+            code: ErrorCode::InternalError,
+            message: format!("Failed to read file: {uri}").into(),
+            data: Some(Value::String(format!("{:?}", err))),
+        })?;
+        let source_parsed = parse(&source).map_err(|err| {
+            let err = err
+                .into_iter()
+                .map(|e| Value::String(e.message))
+                .collect::<Vec<_>>();
+            Error {
+                code: ErrorCode::InternalError,
+                message: format!("Failed to parse file: {uri}").into(),
+                data: Some(Value::Array(err)),
+            }
+        })?;
+
+        // get the formatted text
+        let config = FormatterConfig {
+            line_length: 80,
+            tab_width: params.options.tab_size as _,
+            ..Default::default()
+        };
+        let mut source_formatted = String::new();
+        format(&mut source_formatted, source_parsed, config).map_err(|err| Error {
+            code: ErrorCode::InternalError,
+            message: format!("Failed to format file: {uri}").into(),
+            data: Some(Value::String(format!("{:?}", err))),
+        })?;
+
+        // create a `TextEdit` instance that replaces the contents of the file with the formatted text
+        let text_edit = TextEdit {
+            range: Range {
+                start: Position {
+                    line: 0,
+                    character: 0,
+                },
+                end: Position {
+                    line: u32::max_value(),
+                    character: u32::max_value(),
+                },
+            },
+            new_text: source_formatted,
+        };
+
+        Ok(Some(vec![text_edit]))
+    }
 }
 
 /// Calculate the line and column from the Loc offset received from the parser

vscode/package.json

@@ -51,7 +51,10 @@
 			}
 		},
 		"capabilities": {
-			"hoverProvider": "true"
+			"hoverProvider": "true",
+			"formatting": {
+				"dynamicRegistration": true
+			}
 		},
 		"languages": [
 			{

vscode/src/test/suite/extension.test.ts

@@ -1,7 +1,7 @@
 import * as assert from 'assert';
 
 import * as vscode from 'vscode';
-import { getDocUri, activate } from './helper';
+import { getDocUri, activate, doc } from './helper';
 
 // You can import and use all API from the 'vscode' module
 // as well as import your extension to test it
@@ -110,6 +110,13 @@ suite('Extension Test Suite', function () {
   test('Testing for Rename', async () => {
     await testrename(renamedoc1);
   });
+
+  // Tests for formatting
+  this.timeout(20000);
+  const formatdoc1 = getDocUri('format.sol');
+  test('Testing for Formatting', async () => {
+    await testformat(formatdoc1);
+  });
 });
 
 function toRange(lineno1: number, charno1: number, lineno2: number, charno2: number) {
@@ -464,6 +471,45 @@ async function testrename(docUri: vscode.Uri) {
   assert.strictEqual(loc03.newText, newname0);
 }
 
+async function testformat(docUri: vscode.Uri) {
+  await activate(docUri);
+
+  const options = {
+    tabSize: 4,
+    insertSpaces: false,
+  };
+  const textedits = (await vscode.commands.executeCommand(
+    'vscode.executeFormatDocumentProvider',
+    docUri,
+    options,
+  )) as vscode.TextEdit[];
+  // make sure that the input file is not already formatted
+  assert(textedits.length > 0);
+
+  // undo the changes done during the test
+  const undochanges = async () => {
+    for (let i = 0; i < textedits.length; i++) {
+      await vscode.commands.executeCommand('undo');
+    }
+  };
+
+  try {
+    const workedits = new vscode.WorkspaceEdit();
+    workedits.set(docUri, textedits); 
+    const done = await vscode.workspace.applyEdit(workedits); 
+    assert(done);
+
+    const actualtext = doc.getText();
+    const expectedtext = "contract deck {\n    enum suit {\n        club,\n        diamonds,\n        hearts,\n        spades\n    }\n    enum value {\n        two,\n        three,\n        four,\n        five,\n        six,\n        seven,\n        eight,\n        nine,\n        ten,\n        jack,\n        queen,\n        king,\n        ace\n    }\n\n    struct card {\n        value v;\n        suit s;\n    }\n\n    function score(card c) public returns (uint32 score) {\n        if (c.s == suit.hearts) {\n            if (c.v == value.ace) {\n                score = 14;\n            }\n            if (c.v == value.king) {\n                score = 13;\n            }\n            if (c.v == value.queen) {\n                score = 12;\n            }\n            if (c.v == value.jack) {\n                score = 11;\n            }\n        }\n        // all others score 0\n    }\n}\n";
+    assert.strictEqual(actualtext, expectedtext);
+  } catch (error) {
+    await undochanges();
+    throw error;
+  }
+
+  await undochanges();
+}
+
 async function testhover(docUri: vscode.Uri) {
   await activate(docUri);
 

vscode/src/testFixture/format.sol

@@ -0,0 +1,48 @@
+contract deck {
+    enum
+     suit {
+        club,
+        diamonds,
+        hearts,
+        spades
+    }
+    enum value {
+        two,
+
+
+        three,
+            four,
+        five,
+        six,
+        seven,
+        eight,
+                nine,
+        ten,jack,
+        queen,
+        king,
+        ace
+    }
+    struct card {
+        value    v;
+        suit    s;
+    }
+
+    function score
+     (card c)       public       returns (
+        uint32 score) {
+        if (c.s == suit.hearts) {
+            if (c.v == value.ace) {
+                score = 14;
+            }
+            if ( c.v == value.king) {
+                score = 13;
+            }
+            if (       c.v == value.queen) {
+                score = 12;
+            }
+            if ( c.v  == value.jack) {
+                score  = 11;}
+        }
+        // all others score 0
+    }
+}