angular/modules/@angular/compiler/src/i18n/extractor_merger.ts

490 lines
16 KiB
TypeScript

/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import * as html from '../ml_parser/ast';
import {InterpolationConfig} from '../ml_parser/interpolation_config';
import * as i18n from './i18n_ast';
import * as i18nParser from './i18n_parser';
import * as msgBundle from './message_bundle';
import {I18nError} from './parse_util';
import {TranslationBundle} from './translation_bundle';
const _I18N_ATTR = 'i18n';
const _I18N_ATTR_PREFIX = 'i18n-';
const _I18N_COMMENT_PREFIX_REGEXP = /^i18n:?/;
/**
* Extract translatable messages from an html AST
*/
export function extractMessages(
nodes: html.Node[], interpolationConfig: InterpolationConfig, implicitTags: string[],
implicitAttrs: {[k: string]: string[]}): ExtractionResult {
const visitor = new _Visitor(implicitTags, implicitAttrs);
return visitor.extract(nodes, interpolationConfig);
}
export function mergeTranslations(
nodes: html.Node[], translations: TranslationBundle, interpolationConfig: InterpolationConfig,
implicitTags: string[], implicitAttrs: {[k: string]: string[]}): html.Node[] {
const visitor = new _Visitor(implicitTags, implicitAttrs);
return visitor.merge(nodes, translations, interpolationConfig);
}
export class ExtractionResult {
constructor(public messages: i18n.Message[], public errors: I18nError[]) {}
}
enum _VisitorMode {
Extract,
Merge
}
/**
* This Visitor is used:
* 1. to extract all the translatable strings from an html AST (see `extract()`),
* 2. to replace the translatable strings with the actual translations (see `merge()`)
*
* @internal
*/
class _Visitor implements html.Visitor {
// <el i18n>...</el>
private _inI18nNode = false;
private _depth: number = 0;
// <!--i18n-->...<!--/i18n-->
private _blockMeaningAndDesc: string;
private _blockChildren: html.Node[];
private _blockStartDepth: number;
private _inI18nBlock: boolean;
// {<icu message>}
private _inIcu = false;
private _msgCountAtSectionStart: number;
private _errors: I18nError[];
private _mode: _VisitorMode;
// _VisitorMode.Extract only
private _messages: i18n.Message[];
// _VisitorMode.Merge only
private _translations: TranslationBundle;
private _createI18nMessage:
(msg: html.Node[], meaning: string, description: string) => i18n.Message;
constructor(private _implicitTags: string[], private _implicitAttrs: {[k: string]: string[]}) {}
/**
* Extracts the messages from the tree
*/
extract(nodes: html.Node[], interpolationConfig: InterpolationConfig): ExtractionResult {
this._init(_VisitorMode.Extract, interpolationConfig);
nodes.forEach(node => node.visit(this, null));
if (this._inI18nBlock) {
this._reportError(nodes[nodes.length - 1], 'Unclosed block');
}
return new ExtractionResult(this._messages, this._errors);
}
/**
* Returns a tree where all translatable nodes are translated
*/
merge(
nodes: html.Node[], translations: TranslationBundle,
interpolationConfig: InterpolationConfig): html.Node[] {
this._init(_VisitorMode.Merge, interpolationConfig);
this._translations = translations;
// Construct a single fake root element
const wrapper = new html.Element('wrapper', [], nodes, null, null, null);
const translatedNode = wrapper.visit(this, null);
if (this._inI18nBlock) {
this._reportError(nodes[nodes.length - 1], 'Unclosed block');
}
return translatedNode.children;
}
visitExpansionCase(icuCase: html.ExpansionCase, context: any): any {
// Parse cases for translatable html attributes
const expression = html.visitAll(this, icuCase.expression, context);
if (this._mode === _VisitorMode.Merge) {
return new html.ExpansionCase(
icuCase.value, expression, icuCase.sourceSpan, icuCase.valueSourceSpan,
icuCase.expSourceSpan);
}
}
visitExpansion(icu: html.Expansion, context: any): html.Expansion {
this._mayBeAddBlockChildren(icu);
const wasInIcu = this._inIcu;
if (!this._inIcu) {
// nested ICU messages should not be extracted but top-level translated as a whole
if (this._isInTranslatableSection) {
this._addMessage([icu]);
}
this._inIcu = true;
}
const cases = html.visitAll(this, icu.cases, context);
if (this._mode === _VisitorMode.Merge) {
icu = new html.Expansion(
icu.switchValue, icu.type, cases, icu.sourceSpan, icu.switchValueSourceSpan);
}
this._inIcu = wasInIcu;
return icu;
}
visitComment(comment: html.Comment, context: any): any {
const isOpening = _isOpeningComment(comment);
if (isOpening && this._isInTranslatableSection) {
this._reportError(comment, 'Could not start a block inside a translatable section');
return;
}
const isClosing = _isClosingComment(comment);
if (isClosing && !this._inI18nBlock) {
this._reportError(comment, 'Trying to close an unopened block');
return;
}
if (!this._inI18nNode && !this._inIcu) {
if (!this._inI18nBlock) {
if (isOpening) {
this._inI18nBlock = true;
this._blockStartDepth = this._depth;
this._blockChildren = [];
this._blockMeaningAndDesc = comment.value.replace(_I18N_COMMENT_PREFIX_REGEXP, '').trim();
this._openTranslatableSection(comment);
}
} else {
if (isClosing) {
if (this._depth == this._blockStartDepth) {
this._closeTranslatableSection(comment, this._blockChildren);
this._inI18nBlock = false;
const message = this._addMessage(this._blockChildren, this._blockMeaningAndDesc);
return this._translateMessage(comment, message);
} else {
this._reportError(comment, 'I18N blocks should not cross element boundaries');
return;
}
}
}
}
}
visitText(text: html.Text, context: any): html.Text {
if (this._isInTranslatableSection) {
this._mayBeAddBlockChildren(text);
}
return text;
}
visitElement(el: html.Element, context: any): html.Element {
this._mayBeAddBlockChildren(el);
this._depth++;
const wasInI18nNode = this._inI18nNode;
let childNodes: html.Node[];
// Extract only top level nodes with the (implicit) "i18n" attribute if not in a block or an ICU
// message
const i18nAttr = _getI18nAttr(el);
const isImplicitI18n = this._implicitTags.some((tag: string): boolean => el.name === tag);
if (!this._isInTranslatableSection && !this._inIcu) {
if (i18nAttr) {
// explicit translation
this._inI18nNode = true;
const message = this._addMessage(el.children, i18nAttr.value);
childNodes = this._translateMessage(el, message);
} else if (isImplicitI18n) {
// implicit translation
this._inI18nNode = true;
const message = this._addMessage(el.children);
childNodes = this._translateMessage(el, message);
}
if (this._mode == _VisitorMode.Extract) {
const isTranslatable = i18nAttr || isImplicitI18n;
if (isTranslatable) {
this._openTranslatableSection(el);
}
html.visitAll(this, el.children);
if (isTranslatable) {
this._closeTranslatableSection(el, el.children);
}
}
if (this._mode === _VisitorMode.Merge && !i18nAttr && !isImplicitI18n) {
childNodes = [];
el.children.forEach(child => {
const visited = child.visit(this, context);
if (visited && !this._isInTranslatableSection) {
// Do not add the children from translatable sections (= i18n blocks here)
// They will be added when the section is close (i.e. on `<!-- /i18n -->`)
childNodes = childNodes.concat(visited);
}
});
}
} else {
if (i18nAttr || isImplicitI18n) {
// TODO(vicb): we should probably allow nested implicit element (ie <div>)
this._reportError(
el, 'Could not mark an element as translatable inside a translatable section');
}
if (this._mode == _VisitorMode.Extract) {
// Descend into child nodes for extraction
html.visitAll(this, el.children);
}
if (this._mode == _VisitorMode.Merge) {
// Translate attributes in ICU messages
childNodes = [];
el.children.forEach(child => {
const visited = child.visit(this, context);
if (visited && !this._isInTranslatableSection) {
// Do not add the children from translatable sections (= i18n blocks here)
// They will be added when the section is close (i.e. on `<!-- /i18n -->`)
childNodes = childNodes.concat(visited);
}
});
}
}
this._visitAttributesOf(el);
this._depth--;
this._inI18nNode = wasInI18nNode;
if (this._mode === _VisitorMode.Merge) {
// There are no childNodes in translatable sections - those nodes will be replace anyway
const translatedAttrs = this._translateAttributes(el);
return new html.Element(
el.name, translatedAttrs, childNodes, el.sourceSpan, el.startSourceSpan,
el.endSourceSpan);
}
}
visitAttribute(attribute: html.Attribute, context: any): any {
throw new Error('unreachable code');
}
private _init(mode: _VisitorMode, interpolationConfig: InterpolationConfig): void {
this._mode = mode;
this._inI18nBlock = false;
this._inI18nNode = false;
this._depth = 0;
this._inIcu = false;
this._msgCountAtSectionStart = void 0;
this._errors = [];
this._messages = [];
this._createI18nMessage = i18nParser.createI18nMessageFactory(interpolationConfig);
}
// looks for translatable attributes
private _visitAttributesOf(el: html.Element): void {
const explicitAttrNameToValue: {[k: string]: string} = {};
const implicitAttrNames: string[] = this._implicitAttrs[el.name] || [];
el.attrs.filter(attr => attr.name.startsWith(_I18N_ATTR_PREFIX))
.forEach(
attr => explicitAttrNameToValue[attr.name.slice(_I18N_ATTR_PREFIX.length)] =
attr.value);
el.attrs.forEach(attr => {
if (attr.name in explicitAttrNameToValue) {
this._addMessage([attr], explicitAttrNameToValue[attr.name]);
} else if (implicitAttrNames.some(name => attr.name === name)) {
this._addMessage([attr]);
}
});
}
// add a translatable message
private _addMessage(ast: html.Node[], meaningAndDesc?: string): i18n.Message {
if (ast.length == 0 ||
ast.length == 1 && ast[0] instanceof html.Attribute && !(<html.Attribute>ast[0]).value) {
// Do not create empty messages
return;
}
const [meaning, description] = _splitMeaningAndDesc(meaningAndDesc);
const message = this._createI18nMessage(ast, meaning, description);
this._messages.push(message);
return message;
}
// translate the given message given the `TranslationBundle`
private _translateMessage(el: html.Node, message: i18n.Message): html.Node[] {
if (message && this._mode === _VisitorMode.Merge) {
const id = msgBundle.digestMessage(message.nodes, message.meaning);
const nodes = this._translations.get(id);
if (nodes) {
return nodes;
}
this._reportError(el, `Translation unavailable for message id="${id}"`);
}
return [];
}
// translate the attributes of an element and remove i18n specific attributes
private _translateAttributes(el: html.Element): html.Attribute[] {
const attributes = el.attrs;
const i18nAttributeMeanings: {[name: string]: string} = {};
attributes.forEach(attr => {
if (attr.name.startsWith(_I18N_ATTR_PREFIX)) {
i18nAttributeMeanings[attr.name.slice(_I18N_ATTR_PREFIX.length)] =
_splitMeaningAndDesc(attr.value)[0];
}
});
const translatedAttributes: html.Attribute[] = [];
attributes.forEach((attr) => {
if (attr.name === _I18N_ATTR || attr.name.startsWith(_I18N_ATTR_PREFIX)) {
// strip i18n specific attributes
return;
}
if (i18nAttributeMeanings.hasOwnProperty(attr.name)) {
const meaning = i18nAttributeMeanings[attr.name];
const message: i18n.Message = this._createI18nMessage([attr], meaning, '');
const id = msgBundle.digestMessage(message.nodes, message.meaning);
const nodes = this._translations.get(id);
if (!nodes) {
this._reportError(
el, `Translation unavailable for attribute "${attr.name}" (id="${id}")`);
}
if (nodes[0] instanceof html.Text) {
const value = (nodes[0] as html.Text).value;
translatedAttributes.push(new html.Attribute(attr.name, value, attr.sourceSpan));
}
} else {
translatedAttributes.push(attr);
}
});
return translatedAttributes;
}
/**
* Add the node as a child of the block when:
* - we are in a block,
* - we are not inside a ICU message (those are handled separately),
* - the node is a "direct child" of the block
*/
private _mayBeAddBlockChildren(node: html.Node): void {
if (this._inI18nBlock && !this._inIcu && this._depth == this._blockStartDepth) {
this._blockChildren.push(node);
}
}
/**
* Marks the start of a section, see `_endSection`
*/
private _openTranslatableSection(node: html.Node): void {
if (this._isInTranslatableSection) {
this._reportError(node, 'Unexpected section start');
} else {
this._msgCountAtSectionStart = this._messages.length;
}
}
/**
* A translatable section could be:
* - a translatable element,
* - nodes between `<!-- i18n -->` and `<!-- /i18n -->` comments
*/
private get _isInTranslatableSection(): boolean {
return this._msgCountAtSectionStart !== void 0;
}
/**
* Terminates a section.
*
* If a section has only one significant children (comments not significant) then we should not
* keep the message from this children:
*
* `<p i18n="meaning|description">{ICU message}</p>` would produce two messages:
* - one for the <p> content with meaning and description,
* - another one for the ICU message.
*
* In this case the last message is discarded as it contains less information (the AST is
* otherwise identical).
*
* Note that we should still keep messages extracted from attributes inside the section (ie in the
* ICU message here)
*/
private _closeTranslatableSection(node: html.Node, directChildren: html.Node[]): void {
if (!this._isInTranslatableSection) {
this._reportError(node, 'Unexpected section end');
return;
}
const startIndex = this._msgCountAtSectionStart;
const significantChildren: number = directChildren.reduce(
(count: number, node: html.Node): number => count + (node instanceof html.Comment ? 0 : 1),
0);
if (significantChildren == 1) {
for (let i = this._messages.length - 1; i >= startIndex; i--) {
const ast = this._messages[i].nodes;
if (!(ast.length == 1 && ast[0] instanceof i18n.Text)) {
this._messages.splice(i, 1);
break;
}
}
}
this._msgCountAtSectionStart = void 0;
}
private _reportError(node: html.Node, msg: string): void {
this._errors.push(new I18nError(node.sourceSpan, msg));
}
}
function _isOpeningComment(n: html.Node): boolean {
return n instanceof html.Comment && n.value && n.value.startsWith('i18n');
}
function _isClosingComment(n: html.Node): boolean {
return n instanceof html.Comment && n.value && n.value === '/i18n';
}
function _getI18nAttr(p: html.Element): html.Attribute {
return p.attrs.find(attr => attr.name === _I18N_ATTR) || null;
}
function _splitMeaningAndDesc(i18n: string): [string, string] {
if (!i18n) return ['', ''];
const pipeIndex = i18n.indexOf('|');
return pipeIndex == -1 ? ['', i18n] : [i18n.slice(0, pipeIndex), i18n.slice(pipeIndex + 1)];
}