Formatter infrastructure and BlankLines formatter (#213)

* Formatter styles classes

* Added BlankLines formatter

* typos

* remove unused imports

---------

Co-authored-by: Andrii Rodionov <andriih@moderne.io>

openrewrite/src/core/execution.ts

@@ -1,6 +1,6 @@
 import {createTwoFilesPatch} from 'diff';
 import {PathLike} from 'fs';
-import {Cursor, TreeVisitor} from "./tree";
+import {Cursor, SourceFile, TreeVisitor} from "./tree";
 
 export class Result {
     static diff(before: string, after: string, path: PathLike): string {
@@ -60,10 +60,86 @@ export class DelegatingExecutionContext implements ExecutionContext {
     }
 }
 
+interface LargeSourceSet {
+    edit(map: (source: SourceFile) => SourceFile | null): LargeSourceSet;
+    getChangeSet(): RecipeRunResult[];
+}
+
+export class InMemoryLargeSourceSet implements LargeSourceSet {
+    private readonly initialState?: InMemoryLargeSourceSet;
+    private readonly sources: SourceFile[];
+    private readonly deletions: SourceFile[];
+
+    constructor(sources: SourceFile[], deletions: SourceFile[] = [], initialState?: InMemoryLargeSourceSet) {
+        this.initialState = initialState;
+        this.sources = sources;
+        this.deletions = deletions;
+    }
+
+    edit(map: (source: SourceFile) => SourceFile | null): InMemoryLargeSourceSet {
+        const mapped: SourceFile[] = [];
+        const deleted: SourceFile[] = this.initialState ? [...this.initialState.deletions] : [];
+        let changed = false;
+
+        for (const source of this.sources) {
+            const mappedSource = map(source);
+            if (mappedSource !== null) {
+                mapped.push(mappedSource);
+                changed = mappedSource !== source;
+            } else {
+                deleted.push(source);
+                changed = true;
+            }
+        }
+
+        return changed ? new InMemoryLargeSourceSet(mapped, deleted, this.initialState ?? this) : this;
+    }
+
+    getChangeSet(): RecipeRunResult[] {
+        const sourceFileById = new Map(this.initialState?.sources.map(sf => [sf.id, sf]));
+        const changes: RecipeRunResult[] = [];
+
+        for (const source of this.sources) {
+            const original = sourceFileById.get(source.id) || null;
+            changes.push(new RecipeRunResult(original, source));
+        }
+
+        for (const source of this.deletions) {
+            changes.push(new RecipeRunResult(source, null));
+        }
+
+        return changes;
+    }
+}
+
+export class RecipeRunResult {
+    constructor(
+        public readonly before: SourceFile | null,
+        public readonly after: SourceFile | null
+    ) {}
+}
+
 export class Recipe {
     getVisitor(): TreeVisitor<any, ExecutionContext> {
         return TreeVisitor.noop();
     }
+
+    getRecipeList(): Recipe[] {
+        return [];
+    }
+
+    run(before: LargeSourceSet, ctx: ExecutionContext): RecipeRunResult[] {
+        const lss = this.runInternal(before, ctx, new Cursor(null, Cursor.ROOT_VALUE));
+        return lss.getChangeSet();
+    }
+
+    runInternal(before: LargeSourceSet, ctx: ExecutionContext, root: Cursor): LargeSourceSet {
+        let after = before.edit((beforeFile) => this.getVisitor().visit(beforeFile, ctx, root));
+        for (const recipe of this.getRecipeList()) {
+            after = recipe.runInternal(after, ctx, root);
+        }
+        return after;
+    }
 }
 
 export class RecipeRunException extends Error {
@@ -83,4 +159,4 @@ export class RecipeRunException extends Error {
     get cursor(): Cursor | undefined {
         return this._cursor;
     }
-}
+}

openrewrite/src/core/index.ts

@@ -3,3 +3,4 @@ export * from './markers';
 export * from './parser';
 export * from './tree';
 export * from './utils';
+export * from './style';

openrewrite/src/core/style.ts

@@ -0,0 +1,58 @@
+import {Marker, MarkerSymbol} from "./markers";
+import {UUID} from "./utils";
+
+export abstract class Style {
+    merge(lowerPrecedence: Style): Style {
+        return this;
+    }
+
+    applyDefaults(): Style {
+        return this;
+    }
+}
+
+export class NamedStyles implements Marker {
+    [MarkerSymbol] = true;
+
+    private readonly _id: UUID;
+    name: string;
+    displayName: string;
+    description?: string;
+    tags: Set<string>;
+    styles: Style[];
+
+    constructor(id: UUID, name: string, displayName: string, description?: string, tags: Set<string> = new Set(), styles: Style[] = []) {
+        this._id = id;
+        this.name = name;
+        this.displayName = displayName;
+        this.description = description;
+        this.tags = tags;
+        this.styles = styles;
+    }
+
+    public get id(): UUID {
+        return this._id;
+    }
+
+    public withId(id: UUID): NamedStyles {
+        return id === this._id ? this : new NamedStyles(id, this.name, this.displayName, this.description, this.tags, this.styles);
+    }
+
+    static merge<S extends Style>(styleClass: new (...args: any[]) => S, namedStyles: NamedStyles[]): S | null {
+        let merged: S | null = null;
+
+        for (const namedStyle of namedStyles) {
+            if (namedStyle.styles) {
+                for (let style of namedStyle.styles) {
+                    if (style instanceof styleClass) {
+                        style = style.applyDefaults();
+                        merged = merged ? (merged.merge(style) as S) : (style as S);
+                    }
+                }
+            }
+        }
+
+        return merged;
+    }
+
+}

openrewrite/src/core/tree.ts

@@ -162,12 +162,12 @@ export class Cursor {
 
     private readonly _parent: Cursor | null;
     private readonly _value: Object;
-    private _messages: Map<string, Object>;
+    private _messages: Map<string, any>;
 
     constructor(parent: Cursor | null, value: Object) {
         this._parent = parent;
         this._value = value;
-        this._messages = new Map<string, Object>();
+        this._messages = new Map<string, any>();
     }
 
     get parent(): Cursor | null {
@@ -182,6 +182,17 @@ export class Cursor {
         return new Cursor(this._parent === null ? null : this._parent.fork(), this.value);
     }
 
+    parentTreeCursor(): Cursor {
+        let c: Cursor | null = this.parent;
+        while (c && c.parent) {
+            if (isTree(c.value()) || c.parent.value() === Cursor.ROOT_VALUE) {
+                return c;
+            }
+            c = c.parent;
+        }
+        throw new Error(`Expected to find parent tree cursor for ${c}`);
+    }
+
     firstEnclosing<T>(type: Constructor<T>): T | null {
         let c: Cursor | null = this;
 
@@ -211,6 +222,10 @@ export class Cursor {
     getMessage<T>(key: string, defaultValue?: T | null): T | null {
         return this._messages.get(key) as T || defaultValue!;
     }
+
+    putMessage(key: string, value: any) {
+        this._messages.set(key, value);
+    }
 }
 
 @LstType("org.openrewrite.Checksum")

openrewrite/src/javascript/format/blankLines.ts

@@ -0,0 +1,139 @@
+import * as J from '../../java';
+import * as JS from '..';
+import {ClassDeclaration, Space} from '../../java';
+import {Cursor, InMemoryExecutionContext} from "../../core";
+import {JavaScriptVisitor} from "..";
+import {BlankLinesStyle} from "../style";
+
+export class BlankLinesFormatVisitor extends JavaScriptVisitor<InMemoryExecutionContext> {
+    private style: BlankLinesStyle;
+
+    constructor(style: BlankLinesStyle) {
+        super();
+        this.style = style;
+        this.cursor = new Cursor(null, Cursor.ROOT_VALUE);
+    }
+
+    visitJsCompilationUnit(compilationUnit: JS.CompilationUnit, p: InMemoryExecutionContext): J.J | null {
+        if (compilationUnit.prefix.comments.length == 0) {
+            compilationUnit = compilationUnit.withPrefix(Space.EMPTY);
+        }
+        return super.visitJsCompilationUnit(compilationUnit, p);
+    }
+
+    visitStatement(statement: J.Statement, p: InMemoryExecutionContext): J.J {
+        statement = super.visitStatement(statement, p);
+
+        const parentCursor = this.cursor.parentTreeCursor();
+        const topLevel = parentCursor.value() instanceof JS.CompilationUnit;
+
+        let prevBlankLine: number | null | undefined;
+        const blankLines = this.getBlankLines(statement, parentCursor);
+        if (blankLines) {
+            prevBlankLine = parentCursor.getMessage('prev_blank_line', undefined);
+            parentCursor.putMessage('prev_blank_line', blankLines);
+        } else {
+            prevBlankLine = parentCursor.getMessage('prev_blank_line', undefined);
+            if (prevBlankLine) {
+                parentCursor.putMessage('prev_blank_line', undefined);
+            }
+        }
+
+        if (topLevel) {
+            const isFirstStatement = p.getMessage<boolean>('is_first_statement', true) ?? true;
+            if (isFirstStatement) {
+                p.putMessage('is_first_statement', false);
+            } else {
+                const minLines = statement instanceof JS.JsImport ? 0 : max(prevBlankLine, blankLines);
+                statement = adjustedLinesForTree(statement, minLines, this.style.keepMaximum.inCode);
+            }
+        } else {
+            const inBlock = parentCursor.value() instanceof J.Block;
+            const inClass = inBlock && parentCursor.parentTreeCursor().value() instanceof J.ClassDeclaration;
+            let minLines = 0;
+
+            if (inClass) {
+                const isFirst = (parentCursor.value() as J.Block).statements[0] === statement;
+                minLines = isFirst ? 0 : max(blankLines, prevBlankLine);
+            }
+
+            statement = adjustedLinesForTree(statement, minLines, this.style.keepMaximum.inCode);
+        }
+        return statement;
+    }
+
+    getBlankLines(statement: J.Statement, cursor: Cursor): number | undefined {
+        const inBlock = cursor.value() instanceof J.Block;
+        let type;
+        if (inBlock) {
+            const val = cursor.parentTreeCursor().value();
+            if (val instanceof J.ClassDeclaration) {
+                type = val.padding.kind.type;
+            }
+        }
+
+        if (type === ClassDeclaration.Kind.Type.Interface && (statement instanceof J.MethodDeclaration || statement instanceof JS.JSMethodDeclaration)) {
+            return this.style.minimum.aroundMethodInInterface ?? undefined;
+        } else if (type === ClassDeclaration.Kind.Type.Interface && (statement instanceof J.VariableDeclarations || statement instanceof JS.JSVariableDeclarations)) {
+            return this.style.minimum.aroundFieldInInterface ?? undefined;
+        } else if (type === ClassDeclaration.Kind.Type.Class && (statement instanceof J.VariableDeclarations || statement instanceof JS.JSVariableDeclarations)) {
+            return this.style.minimum.aroundField;
+        } else if (statement instanceof JS.JsImport) {
+            return this.style.minimum.afterImports;
+        } else if (statement instanceof J.ClassDeclaration) {
+            return this.style.minimum.aroundClass;
+        } else if (statement instanceof J.MethodDeclaration || statement instanceof JS.JSMethodDeclaration) {
+            return this.style.minimum.aroundMethod;
+        } else if (statement instanceof JS.FunctionDeclaration) {
+            return this.style.minimum.aroundFunction;
+        } else {
+            return undefined;
+        }
+    }
+
+}
+
+function adjustedLinesForTree(tree: J.J, minLines: number, maxLines: number): J.J {
+
+    if (tree instanceof JS.ScopedVariableDeclarations && tree.padding.scope) {
+        const prefix = tree.padding.scope.before;
+        return tree.padding.withScope(tree.padding.scope.withBefore(adjustedLinesForSpace(prefix, minLines, maxLines)));
+    } else {
+        const prefix = tree.prefix;
+        return tree.withPrefix(adjustedLinesForSpace(prefix, minLines, maxLines));
+    }
+
+}
+
+function adjustedLinesForSpace(prefix: Space, minLines: number, maxLines: number): Space {
+    if (prefix.comments.length == 0 || prefix.whitespace?.includes('\n')) {
+        return prefix.withWhitespace(adjustedLinesForString(prefix.whitespace ?? '', minLines, maxLines));
+    }
+
+    return prefix;
+}
+
+function adjustedLinesForString(whitespace: string, minLines: number, maxLines: number): string {
+    const existingBlankLines = Math.max(countLineBreaks(whitespace) - 1, 0);
+    maxLines = Math.max(minLines, maxLines);
+
+    if (existingBlankLines >= minLines && existingBlankLines <= maxLines) {
+        return whitespace;
+    } else if (existingBlankLines < minLines) {
+        return '\n'.repeat(minLines - existingBlankLines) + whitespace;
+    } else {
+        return '\n'.repeat(maxLines) + whitespace.substring(whitespace.lastIndexOf('\n'));
+    }
+}
+
+function countLineBreaks(whitespace: string): number {
+    return (whitespace.match(/\n/g) || []).length;
+}
+
+function max(x: number | null | undefined, y: number | null | undefined) {
+    if (x && y) {
+        return Math.max(x, y);
+    } else {
+        return x ? x : y ? y : 0;
+    }
+}