full template restoreablity

2026-05-24 12:17:12 +02:00
parent 8ad2545310
commit af0c25e64b
5 changed files with 399 additions and 61 deletions
--- a/README.md
+++ b/README.md
@@ -142,7 +142,7 @@ Pass a string to choose a custom JSON path inside the output directory:
 render("./output", context, { reverseMap: "meta/reverse-map.json" })
 ```

-The map contains a flat lookup from rendered strings to template tokens plus per-file occurrences with path/range context:
+The map contains a flat lookup from rendered strings to template tokens, per-file occurrences with path/range context, inline conditional blocks, and template files skipped by path conditionals:

 ```json
 {
@@ -160,10 +160,27 @@ The map contains a flat lookup from rendered strings to template tokens plus per
          "outputPath": "web/index.html",
          "templatePath": "<@if(context.web)>web/index.html",
          "range": { "start": 16, "end": 21 }
+        },
+        {
+          "kind": "conditional",
+          "result": "<head><@var(context.header.title)></head>",
+          "token": "<@if(context.header.show)><head><@var(context.header.title)></head><@endif>",
+          "outputPath": "web/index.html",
+          "templatePath": "<@if(context.web)>web/index.html",
+          "range": { "start": 9, "end": 53 },
+          "activeRange": { "start": 27, "end": 71 }
        }
      ]
    }
  ],
+  "skipped": [
+    {
+      "kind": "file",
+      "templatePath": "<@if(context.docs)>docs/readme.md",
+      "encoding": "utf8",
+      "content": "# Docs"
+    }
+  ],
  "tokens": {
    "Hello": ["<@var(context.header.title)>"]
  }
@@ -191,7 +208,7 @@ tdir reverse ./output ./templates --map meta/reverse-map.json
 bunx @gregorlohaus/tdir reverse ./output ./templates --map meta/reverse-map.json
 ```

-The command writes files at their original template paths and restores recorded `<@var(...)>` tokens in file contents and file paths. It does not infer conditional blocks that were removed during rendering; keep the original template structure when those blocks need to be preserved.
+The command writes files at their original template paths, restores recorded `<@var(...)>` tokens, wraps edited inline conditional output back in the original conditional block, and restores template files that were skipped by path conditionals.

 ## Unmatched directives

--- a/index.test.ts
+++ b/index.test.ts
@@ -66,6 +66,17 @@ test("render can write a reverse map", () => {

  const file = manifest.files.find((entry: any) => entry.outputPath === join("web", "if_example.html"))
  expect(file).toBeDefined()
+  expect(file.tokens).toContainEqual({
+    kind: "conditional",
+    result: expect.stringContaining("<@var(context.header.text)>"),
+    token: expect.stringContaining("<@if(context.header.render)>"),
+    outputPath: join("web", "if_example.html"),
+    templatePath: join("<@if(context.web)>web", "if_example.html"),
+    range: expect.any(Object),
+    activeRange: expect.any(Object),
+    before: expect.any(String),
+    after: expect.any(String),
+  })
  expect(file.tokens).toContainEqual({
    kind: "content",
    result: "My Title",
@@ -134,10 +145,37 @@ test("reverseDir rebuilds templates from rendered output and map", () => {
  expect(result.warnings).toEqual([])

  const reversed = readFileSync(join(templateOut, "<@if(context.web)>web", "if_example.html"), "utf-8")
+  expect(reversed).toContain("<@if(context.header.render)>")
+  expect(reversed).toContain("<@endif>")
  expect(reversed).toContain("<@var(context.header.text)>")
  expect(reversed).toContain("Edited rendered output")
 })

+test("reverseDir restores files skipped by path conditionals", () => {
+  const createRenderer = initRenderer("./testdata/file_if")
+  const render = createRenderer(z.object({
+      web: z.boolean(),
+      file: z.boolean(),
+      text: z.string()
+  }))
+  const renderedOut = join(tmp, "rendered")
+  const templateOut = join(tmp, "template")
+
+  render(renderedOut,{
+    web: true,
+    file: false,
+    text: "test"
+  }, { reverseMap: true })
+
+  expect(existsSync(join(renderedOut, "web", "example.txt"))).toBe(false)
+
+  const result = reverseDir(renderedOut, templateOut)
+  expect(result.filesWritten).toBe(1)
+  const restoredPath = join(templateOut, "<@if(context.web)>web", "<@if(context.file)>example.txt")
+  expect(existsSync(restoredPath)).toBe(true)
+  expect(readFileSync(restoredPath, "utf-8")).toContain("<@var(context.text)>")
+})
+
 test("reverseDir supports custom map paths", () => {
  const createRenderer = initRenderer("./testdata/var_in_path")
  const render = createRenderer(z.object({
--- a/index.ts
+++ b/index.ts
@@ -2,7 +2,7 @@ import { z } from "zod"
 import { parse, type TemplateVariable } from "./parser"
 import { renderDir, type RenderOptions } from "./render"

-export type { RenderOptions, ReverseMapFile, ReverseMapManifest, ReverseMapToken } from "./render"
+export type { RenderOptions, ReverseMapFile, ReverseMapManifest, ReverseMapStoredTemplate, ReverseMapToken } from "./render"
 export { reverseDir, type ReverseOptions, type ReverseResult, type ReverseWarning } from "./reverse"

 interface Stringable {
--- a/render.ts
+++ b/render.ts
@@ -18,7 +18,7 @@ const EQ_RE = /^eq\(context\.(.+?),\s*"(.*)"\)$/
 const PATH_RE = /^context\.(.+)$/

 export type ReverseMapToken = {
-  kind: "path" | "content"
+  kind: "path" | "content" | "conditional"
  result: string
  token: string
  contextPath?: string
@@ -28,6 +28,12 @@ export type ReverseMapToken = {
    start: number
    end: number
  }
+  activeRange?: {
+    start: number
+    end: number
+  }
+  before?: string
+  after?: string
 }

 export type ReverseMapFile = {
@@ -36,9 +42,17 @@ export type ReverseMapFile = {
  tokens: ReverseMapToken[]
 }

+export type ReverseMapStoredTemplate = {
+  kind: "directory" | "file"
+  templatePath: string
+  encoding?: "utf8" | "base64"
+  content?: string
+}
+
 export type ReverseMapManifest = {
  version: 1
  files: ReverseMapFile[]
+  skipped: ReverseMapStoredTemplate[]
  tokens: Record<string, string[]>
 }

@@ -110,7 +124,7 @@ function resolveOutputPath(destRoot: string, outputName: string): string {
 }

 function createReverseMapManifest(): ReverseMapManifest {
-  return { version: 1, files: [], tokens: {} }
+  return { version: 1, files: [], skipped: [], tokens: {} }
 }

 function addReverseMapToken(
@@ -176,70 +190,190 @@ function isUtf8Text(buffer: Buffer): boolean {
  }
 }

-// Each stack frame tracks: did any branch match yet, is the current branch active
-type IfFrame = { matched: boolean; active: boolean; sawElse: boolean }
+type DirectiveToken = {
+  type: "if" | "elseif" | "else" | "endif"
+  condition?: string
+  index: number
+  end: number
+}

-function processIfBlocks(content: string, context: Record<string, unknown>): string {
+type TextNode = {
+  type: "text"
+  text: string
+}
+
+type IfBranch = {
+  type: "if" | "elseif" | "else"
+  condition?: string
+  nodes: TemplateNode[]
+  contentStart: number
+  contentEnd: number
+}
+
+type IfNode = {
+  type: "if"
+  sourceStart: number
+  sourceEnd: number
+  source: string
+  branches: IfBranch[]
+}
+
+type TemplateNode = TextNode | IfNode
+
+type ConditionalRender = {
+  result: string
+  token: string
+  range: {
+    start: number
+    end: number
+  }
+  activeRange: {
+    start: number
+    end: number
+  }
+}
+
+function getDirectiveTokens(content: string): DirectiveToken[] {
+  return Array.from(content.matchAll(DIRECTIVE_RE), match => ({
+    type: match[1] as DirectiveToken["type"],
+    condition: match[2],
+    index: match.index!,
+    end: match.index! + match[0].length,
+  }))
+}
+
+function parseNodes(
+  content: string,
+  tokens: DirectiveToken[],
+  tokenIndex: number,
+  pos: number,
+  stopTypes: DirectiveToken["type"][],
+): {
+  nodes: TemplateNode[]
+  pos: number
+  tokenIndex: number
+  stop?: DirectiveToken
+} {
+  const nodes: TemplateNode[] = []
+
+  while (tokenIndex < tokens.length) {
+    const token = tokens[tokenIndex]!
+    if (stopTypes.includes(token.type)) {
+      if (token.index > pos) nodes.push({ type: "text", text: content.slice(pos, token.index) })
+      return { nodes, pos: token.index, tokenIndex, stop: token }
+    }
+
+    if (token.type !== "if") {
+      throw new Error(`Unexpected <@${token.type}> without <@if>`)
+    }
+
+    if (token.index > pos) nodes.push({ type: "text", text: content.slice(pos, token.index) })
+    const parsed = parseIfNode(content, tokens, tokenIndex)
+    nodes.push(parsed.node)
+    tokenIndex = parsed.tokenIndex
+    pos = parsed.pos
+  }
+
+  if (pos < content.length) nodes.push({ type: "text", text: content.slice(pos) })
+  return { nodes, pos: content.length, tokenIndex }
+}
+
+function parseIfNode(content: string, tokens: DirectiveToken[], tokenIndex: number) {
+  const firstToken = tokens[tokenIndex]!
+  const sourceStart = firstToken.index
+  const branches: IfBranch[] = []
+  let branchType: IfBranch["type"] = "if"
+  let branchCondition = firstToken.condition
+  let branchContentStart = firstToken.end
+  tokenIndex += 1
+
+  while (true) {
+    const parsed = parseNodes(content, tokens, tokenIndex, branchContentStart, ["elseif", "else", "endif"])
+    if (!parsed.stop) throw new Error("Unmatched <@if> without <@endif>")
+
+    branches.push({
+      type: branchType,
+      condition: branchCondition,
+      nodes: parsed.nodes,
+      contentStart: branchContentStart,
+      contentEnd: parsed.pos,
+    })
+
+    if (parsed.stop.type === "endif") {
+      const sourceEnd = parsed.stop.end
+      return {
+        node: {
+          type: "if" as const,
+          sourceStart,
+          sourceEnd,
+          source: content.slice(sourceStart, sourceEnd),
+          branches,
+        },
+        pos: sourceEnd,
+        tokenIndex: parsed.tokenIndex + 1,
+      }
+    }
+
+    branchType = parsed.stop.type
+    branchCondition = parsed.stop.condition
+    branchContentStart = parsed.stop.end
+    tokenIndex = parsed.tokenIndex + 1
+  }
+}
+
+function getActiveBranch(node: IfNode, context: Record<string, unknown>): IfBranch | undefined {
+  for (const branch of node.branches) {
+    if (branch.type === "else" || evalCondition(branch.condition, context)) return branch
+  }
+  return undefined
+}
+
+function renderNodes(
+  nodes: TemplateNode[],
+  context: Record<string, unknown>,
+  conditionalTokens: ConditionalRender[],
+  outputStart = 0,
+): string {
  let result = ""
-  let pos = 0
-  const stack: IfFrame[] = []

-  const re = new RegExp(DIRECTIVE_RE.source, "g")
-  let match: RegExpExecArray | null
-
-  function isEmitting(): boolean {
-    return stack.every(f => f.active)
+  for (const node of nodes) {
+    if (node.type === "text") {
+      result += node.text
+      continue
    }

-  while ((match = re.exec(content)) !== null) {
-    const directive = match[1]!
-    const condPath = match[2]
-
-    if (directive === "if") {
-      if (isEmitting()) result += content.slice(pos, match.index)
-      const truthy = evalCondition(condPath, context)
-      stack.push({ matched: truthy, active: truthy, sawElse: false })
-      pos = re.lastIndex
-    } else if (directive === "elseif") {
-      if (stack.length === 0) throw new Error("Unexpected <@elseif> without <@if>")
-      const top = stack[stack.length - 1]!
-      if (top.sawElse) throw new Error("Unexpected <@elseif> after <@else>")
-      // Emit text before this directive if current branch was active
-      if (isEmitting()) result += content.slice(pos, match.index)
-      if (top.matched) {
-        // A previous branch already matched — skip this one
-        top.active = false
-      } else {
-        const truthy = evalCondition(condPath, context)
-        top.matched = truthy
-        top.active = truthy
-      }
-      pos = re.lastIndex
-    } else if (directive === "else") {
-      if (stack.length === 0) throw new Error("Unexpected <@else> without <@if>")
-      const top = stack[stack.length - 1]!
-      if (top.sawElse) throw new Error("Unexpected duplicate <@else>")
-      if (isEmitting()) result += content.slice(pos, match.index)
-      top.active = !top.matched
-      top.matched = true
-      top.sawElse = true
-      pos = re.lastIndex
-    } else if (directive === "endif") {
-      if (stack.length === 0) throw new Error("Unexpected <@endif> without <@if>")
-      if (isEmitting()) result += content.slice(pos, match.index)
-      stack.pop()
-      pos = re.lastIndex
+    const activeBranch = getActiveBranch(node, context)
+    const start = outputStart + result.length
+    const renderedBranch = activeBranch
+      ? renderNodes(activeBranch.nodes, context, conditionalTokens, start)
+      : ""
+    result += renderedBranch
+    conditionalTokens.push({
+      result: renderedBranch,
+      token: node.source,
+      range: { start, end: start + renderedBranch.length },
+      activeRange: activeBranch
+        ? {
+          start: activeBranch.contentStart - node.sourceStart,
+          end: activeBranch.contentEnd - node.sourceStart,
        }
+        : { start: node.source.length, end: node.source.length },
+    })
  }

-  if (stack.length > 0) {
-    throw new Error("Unmatched <@if> without <@endif>")
-  }
-
-  result += content.slice(pos)
  return result
 }

+function processIfBlocksWithMap(content: string, context: Record<string, unknown>) {
+  const tokens = getDirectiveTokens(content)
+  const parsed = parseNodes(content, tokens, 0, 0, [])
+  const conditionalTokens: ConditionalRender[] = []
+  return {
+    content: renderNodes(parsed.nodes, context, conditionalTokens),
+    conditionalTokens,
+  }
+}
+
 function renderContent(content: string, context: Record<string, unknown>): string {
  return renderContentWithMap(content, context)
 }
@@ -250,7 +384,22 @@ function renderContentWithMap(
  state?: RenderState,
  file?: ReverseMapFile,
 ): string {
-  const processed = processIfBlocks(content, context)
+  const processedResult = processIfBlocksWithMap(content, context)
+  const processed = processedResult.content
+  for (const token of processedResult.conditionalTokens) {
+    addReverseMapToken(state, file, {
+      kind: "conditional",
+      result: token.result,
+      token: token.token,
+      outputPath: file?.outputPath ?? "",
+      templatePath: file?.templatePath ?? "",
+      range: token.range,
+      activeRange: token.activeRange,
+      before: processed.slice(0, token.range.start),
+      after: processed.slice(token.range.end),
+    })
+  }
+
  let result = ""
  let pos = 0

@@ -321,6 +470,39 @@ function validateOutputPaths(
  }
 }

+function storeSkippedTemplate(srcPath: string, state: RenderState) {
+  if (!state.manifest) return
+
+  const stat = statSync(srcPath)
+  const templatePath = relative(state.sourceRoot, srcPath)
+  if (stat.isDirectory()) {
+    state.manifest.skipped.push({ kind: "directory", templatePath })
+    for (const entry of readdirSync(srcPath).sort()) {
+      storeSkippedTemplate(resolvePath(srcPath, entry), state)
+    }
+    return
+  }
+
+  if (!stat.isFile()) return
+
+  const content = readFileSync(srcPath)
+  if (isUtf8Text(content)) {
+    state.manifest.skipped.push({
+      kind: "file",
+      templatePath,
+      encoding: "utf8",
+      content: content.toString("utf-8"),
+    })
+  } else {
+    state.manifest.skipped.push({
+      kind: "file",
+      templatePath,
+      encoding: "base64",
+      content: content.toString("base64"),
+    })
+  }
+}
+
 function renderDirInner(
  srcDir: string,
  destDir: string,
@@ -340,7 +522,10 @@ function renderDirInner(
      tokens: [],
    }
    const outputName = getOutputName(entry, context, state, tempFile)
-    if (outputName === null) continue
+    if (outputName === null) {
+      storeSkippedTemplate(srcPath, state)
+      continue
+    }

    const destPath = resolveOutputPath(destDir, outputName)
    const outputPath = relative(state.destRoot, destPath)
@@ -362,7 +547,7 @@ function renderDirInner(
      } else {
        copyFileSync(srcPath, destPath)
      }
-      if (tempFile.tokens.length > 0) state.manifest?.files.push(tempFile)
+      if (state.manifest) state.manifest.files.push(tempFile)
    }
  }
 }
--- a/reverse.ts
+++ b/reverse.ts
@@ -8,7 +8,7 @@ import {
 } from "node:fs"
 import { dirname, isAbsolute, relative, resolve as resolvePath } from "node:path"
 import { TextDecoder } from "node:util"
-import type { ReverseMapFile, ReverseMapManifest, ReverseMapToken } from "./render"
+import type { ReverseMapFile, ReverseMapManifest, ReverseMapStoredTemplate, ReverseMapToken } from "./render"

 export type ReverseOptions = {
  mapPath?: string
@@ -71,17 +71,73 @@ function replaceFirst(content: string, token: ReverseMapToken): string | null {
  return `${content.slice(0, index)}${token.token}${content.slice(index + token.result.length)}`
 }

+function applyActiveBranch(token: ReverseMapToken, branchContent: string): string {
+  if (!token.activeRange) return token.token
+  return [
+    token.token.slice(0, token.activeRange.start),
+    branchContent,
+    token.token.slice(token.activeRange.end),
+  ].join("")
+}
+
+function findPrefixEnd(content: string, before: string): number {
+  if (before === "") return 0
+  let candidate = before
+  while (candidate.length >= 8) {
+    const index = content.indexOf(candidate)
+    if (index !== -1) return index + candidate.length
+    candidate = candidate.slice(-Math.max(1, Math.floor(candidate.length / 2)))
+  }
+  return -1
+}
+
+function findSuffixStart(content: string, after: string, from: number): number {
+  if (after === "") return content.length
+  let candidate = after
+  while (candidate.length >= 8) {
+    const index = content.indexOf(candidate, from)
+    if (index !== -1) return index
+    candidate = candidate.slice(0, Math.floor(candidate.length / 2))
+  }
+  return -1
+}
+
+function replaceConditional(content: string, token: ReverseMapToken): string | null {
+  const exactIndex = content.indexOf(token.result)
+  if (exactIndex !== -1) {
+    return [
+      content.slice(0, exactIndex),
+      token.token,
+      content.slice(exactIndex + token.result.length),
+    ].join("")
+  }
+
+  if (token.before === undefined || token.after === undefined) return null
+
+  const branchStart = findPrefixEnd(content, token.before)
+  if (branchStart === -1) return null
+
+  const afterIndex = findSuffixStart(content, token.after, branchStart)
+  if (afterIndex === -1) return null
+
+  return [
+    content.slice(0, branchStart),
+    applyActiveBranch(token, content.slice(branchStart, afterIndex)),
+    content.slice(afterIndex),
+  ].join("")
+}
+
 function reverseContent(
  content: string,
  file: ReverseMapFile,
  warnings: ReverseWarning[],
 ): string {
-  const tokens = file.tokens
+  const contentTokens = file.tokens
    .filter(token => token.kind === "content")
    .sort((a, b) => (b.range?.start ?? -1) - (a.range?.start ?? -1))

  let reversed = content
-  for (const token of tokens) {
+  for (const token of contentTokens) {
    const rangeResult = replaceAtRange(reversed, token)
    if (rangeResult !== null) {
      reversed = rangeResult
@@ -101,9 +157,47 @@ function reverseContent(
      message: "Rendered value was not found; token was not restored",
    })
  }
+
+  const conditionalTokens = file.tokens
+    .filter(token => token.kind === "conditional")
+    .sort((a, b) => (b.range?.start ?? -1) - (a.range?.start ?? -1))
+
+  for (const token of conditionalTokens) {
+    const result = replaceConditional(reversed, token)
+    if (result !== null) {
+      reversed = result
+      continue
+    }
+
+    warnings.push({
+      outputPath: file.outputPath,
+      token: token.token,
+      result: token.result,
+      message: "Rendered conditional block was not found; block was not restored",
+    })
+  }
+
  return reversed
 }

+function writeSkippedTemplate(
+  templateRoot: string,
+  skipped: ReverseMapStoredTemplate,
+): number {
+  const templatePath = resolveInside(templateRoot, skipped.templatePath)
+  if (skipped.kind === "directory") {
+    mkdirSync(templatePath, { recursive: true })
+    return 0
+  }
+
+  mkdirSync(dirname(templatePath), { recursive: true })
+  const content = skipped.encoding === "base64"
+    ? Buffer.from(skipped.content ?? "", "base64")
+    : skipped.content ?? ""
+  writeFileSync(templatePath, content)
+  return 1
+}
+
 export function reverseDir(
  renderedDir: string,
  templateDir: string,
@@ -154,5 +248,9 @@ export function reverseDir(
    filesWritten += 1
  }

+  for (const skipped of manifest.skipped ?? []) {
+    filesWritten += writeSkippedTemplate(templateRoot, skipped)
+  }
+
  return { filesWritten, warnings }
 }