Quelle js-property-provider.js Sprache: JAVA

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

"use strict";

const DevToolsUtils = require("resource://devtools/shared/DevToolsUtils.js");

const {
  evalWithDebugger,
} = require("resource://devtools/server/actors/webconsole/eval-with-debugger.js");

if (!isWorker) {
  loader.lazyRequireGetter(
    this,
    "getSyntaxTrees",
    "resource://devtools/shared/webconsole/parser-helper.js",
    true
  );
}
const lazy = {};
if (!isWorker) {
  ChromeUtils.defineESModuleGetters(
    lazy,
    {
      Reflect: "resource://gre/modules/reflect.sys.mjs",
    },
    { global: "contextual" }
  );
}
loader.lazyRequireGetter(
  this,
  [
    "analyzeInputString",
    "shouldInputBeAutocompleted",
    "shouldInputBeEagerlyEvaluated",
  ],
  "resource://devtools/shared/webconsole/analyze-input-string.js",
  true
);

// Provide an easy way to bail out of even attempting an autocompletion
// if an object has way too many properties. Protects against large objects
// with numeric values that wouldn't be tallied towards MAX_AUTOCOMPLETIONS.
const MAX_AUTOCOMPLETE_ATTEMPTS = (exports.MAX_AUTOCOMPLETE_ATTEMPTS = 100000);
// Prevent iterating over too many properties during autocomplete suggestions.
const MAX_AUTOCOMPLETIONS = (exports.MAX_AUTOCOMPLETIONS = 1500);

/**
* Provides a list of properties, that are possible matches based on the passed
* Debugger.Environment/Debugger.Object and inputValue.
*
* @param {Object} An object of the following shape:
* - {Object} dbgObject
*        When the debugger is not paused this Debugger.Object wraps
*        the scope for autocompletion.
*        It is null if the debugger is paused.
* - {Object} environment
*        When the debugger is paused this Debugger.Environment is the
*        scope for autocompletion.
*        It is null if the debugger is not paused.
* - {String} inputValue
*        Value that should be completed.
* - {Number} cursor (defaults to inputValue.length).
*        Optional offset in the input where the cursor is located. If this is
*        omitted then the cursor is assumed to be at the end of the input
*        value.
* - {Array} authorizedEvaluations (defaults to []).
*        Optional array containing all the different properties access that the engine
*        can execute in order to retrieve its result's properties.
*        ⚠️ This should be set to true *ONLY* on user action as it may cause side-effects
*        in the content page ⚠️
* - {WebconsoleActor} webconsoleActor
*        A reference to a webconsole actor which we can use to retrieve the last
*        evaluation result or create a debuggee value.
* - {String}: selectedNodeActor
*        The actor id of the selected node in the inspector.
* - {Array<string>}: expressionVars
*        Optional array containing variable defined in the expression. Those variables
*        are extracted from CodeMirror state.
* @returns null or object
*          If the inputValue is an unsafe getter and invokeUnsafeGetter is false, the
*          following form is returned:
*
*          {
*            isUnsafeGetter: true,
*            getterPath: {Array<String>} An array of the property chain leading to the
*                        getter. Example: ["x", "myGetter"]
*          }
*
*          If no completion valued could be computed, and the input is not an unsafe
*          getter, null is returned.
*
*          Otherwise an object with the following form is returned:
*            {
*              matches: Set<string>
*              matchProp: Last part of the inputValue that was used to find
*                         the matches-strings.
*              isElementAccess: Boolean set to true if the evaluation is an element
*                               access (e.g. `window["addEvent`).
*            }
*/
// eslint-disable-next-line complexity
function jsPropertyProvider({
  dbgObject,
  environment,
  frameActorId,
  inputValue,
  cursor,
  authorizedEvaluations = [],
  webconsoleActor,
  selectedNodeActor,
  expressionVars = [],
}) {
  if (cursor === undefined) {
    cursor = inputValue.length;
  }

  inputValue = inputValue.substring(0, cursor);

  // Analyse the inputValue and find the beginning of the last part that
  // should be completed.
  const inputAnalysis = analyzeInputString(inputValue);

  if (!shouldInputBeAutocompleted(inputAnalysis)) {
    return null;
  }

  let {
    lastStatement,
    isElementAccess,
    mainExpression,
    matchProp,
    isPropertyAccess,
  } = inputAnalysis;

  // Eagerly evaluate the main expression and return the results properties.
  // e.g. `obj.func().a` will evaluate `obj.func()` and return properties matching `a`.
  // NOTE: this is only useful when the input has a property access.
  if (webconsoleActor && shouldInputBeEagerlyEvaluated(inputAnalysis)) {
    const eagerResponse = evalWithDebugger(
      mainExpression,
      { eager: true, selectedNodeActor, frameActor: frameActorId },
      webconsoleActor
    );

    const ret = eagerResponse?.result?.return;

    // Only send matches if eager evaluation returned something meaningful
    if (ret && ret !== undefined) {
      const matches =
        typeof ret != "object"
          ? getMatchedProps(ret, matchProp)
          : getMatchedPropsInDbgObject(ret, matchProp);

      return prepareReturnedObject({
        matches,
        search: matchProp,
        isElementAccess,
      });
    }
  }

  // AST representation of the expression before the last access char (`.` or `[`).
  let astExpression;
  const startQuoteRegex = /^('|"|`)/;
  const env = environment || dbgObject.asEnvironment();

  // Catch literals like [1,2,3] or "foo" and return the matches from
  // their prototypes.
  // Don't run this is a worker, migrating to acorn should allow this
  // to run in a worker - Bug 1217198.
  if (!isWorker && isPropertyAccess) {
    const syntaxTrees = getSyntaxTrees(mainExpression);
    const lastTree = syntaxTrees[syntaxTrees.length - 1];
    const lastBody = lastTree?.body[lastTree.body.length - 1];

    // Finding the last expression since we've sliced up until the dot.
    // If there were parse errors this won't exist.
    if (lastBody) {
      if (!lastBody.expression) {
        return null;
      }

      astExpression = lastBody.expression;
      let matchingObject;

      if (astExpression.type === "ArrayExpression") {
        matchingObject = getContentPrototypeObject(env, "Array");
      } else if (
        astExpression.type === "Literal" &&
        typeof astExpression.value === "string"
      ) {
        matchingObject = getContentPrototypeObject(env, "String");
      } else if (
        astExpression.type === "Literal" &&
        Number.isFinite(astExpression.value)
      ) {
        // The parser rightfuly indicates that we have a number in some cases (e.g. `1.`),
        // but we don't want to return Number proto properties in that case since
        // the result would be invalid (i.e. `1.toFixed()` throws).
        // So if the expression value is an integer, it should not end with `{Number}.`
        // (but the following are fine: `1..`, `(1.).`).
        if (
          !Number.isInteger(astExpression.value) ||
          /\d[^\.]{0}\.$/.test(lastStatement) === false
        ) {
          matchingObject = getContentPrototypeObject(env, "Number");
        } else {
          return null;
        }
      }

      if (matchingObject) {
        let search = matchProp;

        let elementAccessQuote;
        if (isElementAccess && startQuoteRegex.test(matchProp)) {
          elementAccessQuote = matchProp[0];
          search = matchProp.replace(startQuoteRegex, "");
        }

        let props = getMatchedPropsInDbgObject(matchingObject, search);

        if (isElementAccess) {
          props = wrapMatchesInQuotes(props, elementAccessQuote);
        }

        return {
          isElementAccess,
          matchProp,
          matches: props,
        };
      }
    }
  }

  // We are completing a variable / a property lookup.
  let properties = [];

  if (astExpression) {
    if (isPropertyAccess) {
      properties = getPropertiesFromAstExpression(astExpression);

      if (properties === null) {
        return null;
      }
    }
  } else {
    properties = lastStatement.split(".");
    if (isElementAccess) {
      const lastPart = properties[properties.length - 1];
      const openBracketIndex = lastPart.lastIndexOf("[");
      matchProp = lastPart.substr(openBracketIndex + 1);
      properties[properties.length - 1] = lastPart.substring(
        0,
        openBracketIndex
      );
    } else {
      matchProp = properties.pop().trimLeft();
    }
  }

  let search = matchProp;
  let elementAccessQuote;
  if (isElementAccess && startQuoteRegex.test(search)) {
    elementAccessQuote = search[0];
    search = search.replace(startQuoteRegex, "");
  }

  let obj = dbgObject;
  if (properties.length === 0) {
    const environmentProperties = getMatchedPropsInEnvironment(env, search);
    const expressionVariables = new Set(
      expressionVars.filter(variableName => variableName.startsWith(matchProp))
    );

    for (const prop of environmentProperties) {
      expressionVariables.add(prop);
    }

    return {
      isElementAccess,
      matchProp,
      matches: expressionVariables,
    };
  }

  let firstProp = properties.shift();
  if (typeof firstProp == "string") {
    firstProp = firstProp.trim();
  }

  if (firstProp === "this") {
    // Special case for 'this' - try to get the Object from the Environment.
    // No problem if it throws, we will just not autocomplete.
    try {
      obj = env.object;
    } catch (e) {
      // Ignore.
    }
  } else if (firstProp === "$_" && webconsoleActor) {
    obj = webconsoleActor.getLastConsoleInputEvaluation();
  } else if (firstProp === "$0" && selectedNodeActor && webconsoleActor) {
    const actor = webconsoleActor.conn.getActor(selectedNodeActor);
    if (actor) {
      try {
        obj = webconsoleActor.makeDebuggeeValue(actor.rawNode);
      } catch (e) {
        // Ignore.
      }
    }
  } else if (hasArrayIndex(firstProp)) {
    obj = getArrayMemberProperty(null, env, firstProp);
  } else {
    obj = getVariableInEnvironment(env, firstProp);
  }

  if (!isObjectUsable(obj)) {
    return null;
  }

  // We get the rest of the properties recursively starting from the
  // Debugger.Object that wraps the first property
  for (let [index, prop] of properties.entries()) {
    if (typeof prop === "string") {
      prop = prop.trim();
    }

    if (prop === undefined || prop === null || prop === "") {
      return null;
    }

    const propPath = [firstProp].concat(properties.slice(0, index + 1));
    const authorized = authorizedEvaluations.some(
      x => JSON.stringify(x) === JSON.stringify(propPath)
    );

    if (!authorized && DevToolsUtils.isUnsafeGetter(obj, prop)) {
      // If we try to access an unsafe getter, return its name so we can consume that
      // on the frontend.
      return {
        isUnsafeGetter: true,
        getterPath: propPath,
      };
    }

    if (hasArrayIndex(prop)) {
      // The property to autocomplete is a member of array. For example
      // list[i][j]..[n]. Traverse the array to get the actual element.
      obj = getArrayMemberProperty(obj, null, prop);
    } else {
      obj = DevToolsUtils.getProperty(obj, prop, authorized);
    }

    if (!isObjectUsable(obj)) {
      return null;
    }
  }

  const matches =
    typeof obj != "object"
      ? getMatchedProps(obj, search)
      : getMatchedPropsInDbgObject(obj, search);
  return prepareReturnedObject({
    matches,
    search,
    isElementAccess,
    elementAccessQuote,
  });
}

function hasArrayIndex(str) {
  return /\[\d+\]$/.test(str);
}

/**
* For a given environment and constructor name, returns its Debugger.Object wrapped
* prototype.
*
* @param {Environment} env
* @param {String} name: Name of the constructor object we want the prototype of.
* @returns {Debugger.Object|null} the prototype, or null if it not found.
*/
function getContentPrototypeObject(env, name) {
  // Retrieve the outermost environment to get the global object.
  let outermostEnv = env;
  while (outermostEnv?.parent) {
    outermostEnv = outermostEnv.parent;
  }

  const constructorObj = DevToolsUtils.getProperty(outermostEnv.object, name);
  if (!constructorObj) {
    return null;
  }

  return DevToolsUtils.getProperty(constructorObj, "prototype");
}

/**
* @param {Object} ast: An AST representing a property access (e.g. `foo.bar["baz"].x`)
* @returns {Array|null} An array representing the property access
*                       (e.g. ["foo", "bar", "baz", "x"]).
*/
function getPropertiesFromAstExpression(ast) {
  let result = [];
  if (!ast) {
    return result;
  }
  const { type, property, object, name, expression } = ast;
  if (type === "ThisExpression") {
    result.unshift("this");
  } else if (type === "Identifier" && name) {
    result.unshift(name);
  } else if (type === "OptionalExpression" && expression) {
    result = (getPropertiesFromAstExpression(expression) || []).concat(result);
  } else if (
    type === "MemberExpression" ||
    type === "OptionalMemberExpression"
  ) {
    if (property) {
      if (property.type === "Identifier" && property.name) {
        result.unshift(property.name);
      } else if (property.type === "Literal") {
        result.unshift(property.value);
      }
    }
    if (object) {
      result = (getPropertiesFromAstExpression(object) || []).concat(result);
    }
  } else {
    return null;
  }
  return result;
}

function wrapMatchesInQuotes(matches, quote = `"`) {
  return new Set(
    [...matches].map(p => {
      // Escape as a double-quoted string literal
      p = JSON.stringify(p);

      // We don't have to do anything more when using double quotes
      if (quote == `"`) {
        return p;
      }

      // Remove surrounding double quotes
      p = p.slice(1, -1);

      // Unescape inner double quotes (all must be escaped, so no need to count backslashes)
      p = p.replace(/\\(?=")/g, "");

      // Escape the specified quote (assuming ' or `, which are treated literally in regex)
      p = p.replace(new RegExp(quote, "g"), "\\$&");

      // Template literals treat ${ specially, escape it
      if (quote == "`") {
        p = p.replace(/\${/g, "\\$&");
      }

      // Surround the result with quotes
      return `${quote}${p}${quote}`;
    })
  );
}

/**
* Get the array member of obj for the given prop. For example, given
* prop='list[0][1]' the element at [0][1] of obj.list is returned.
*
* @param object obj
*        The object to operate on. Should be null if env is passed.
* @param object env
*        The Environment to operate in. Should be null if obj is passed.
* @param string prop
*        The property to return.
* @return null or Object
*         Returns null if the property couldn't be located. Otherwise the array
*         member identified by prop.
*/
function getArrayMemberProperty(obj, env, prop) {
  // First get the array.
  const propWithoutIndices = prop.substr(0, prop.indexOf("["));

  if (env) {
    obj = getVariableInEnvironment(env, propWithoutIndices);
  } else {
    obj = DevToolsUtils.getProperty(obj, propWithoutIndices);
  }

  if (!isObjectUsable(obj)) {
    return null;
  }

  // Then traverse the list of indices to get the actual element.
  let result;
  const arrayIndicesRegex = /\[[^\]]*\]/g;
  while ((result = arrayIndicesRegex.exec(prop)) !== null) {
    const indexWithBrackets = result[0];
    const indexAsText = indexWithBrackets.substr(
      1,
      indexWithBrackets.length - 2
    );
    const index = parseInt(indexAsText, 10);

    if (isNaN(index)) {
      return null;
    }

    obj = DevToolsUtils.getProperty(obj, index);

    if (!isObjectUsable(obj)) {
      return null;
    }
  }

  return obj;
}

/**
* Check if the given Debugger.Object can be used for autocomplete.
*
* @param Debugger.Object object
*        The Debugger.Object to check.
* @return boolean
*         True if further inspection into the object is possible, or false
*         otherwise.
*/
function isObjectUsable(object) {
  if (object == null) {
    return false;
  }

  if (typeof object == "object" && object.class == "DeadObject") {
    return false;
  }

  return true;
}

/**
* @see getExactMatchImpl()
*/
function getVariableInEnvironment(environment, name) {
  return getExactMatchImpl(environment, name, DebuggerEnvironmentSupport);
}

function prepareReturnedObject({
  matches,
  search,
  isElementAccess,
  elementAccessQuote,
}) {
  if (isElementAccess) {
    // If it's an element access, we need to wrap properties in quotes (either the one
    // the user already typed, or `"`).

    matches = wrapMatchesInQuotes(matches, elementAccessQuote);
  } else if (!isWorker) {
    // If we're not performing an element access, we need to check that the property
    // are suited for a dot access. (reflect.sys.mjs is not available in worker context yet,
    // see Bug 1507181).
    for (const match of matches) {
      try {
        // In order to know if the property is suited for dot notation, we use Reflect
        // to parse an expression where we try to access the property with a dot. If it
        // throws, this means that we need to do an element access instead.
        lazy.Reflect.parse(`({${match}: true})`);
      } catch (e) {
        matches.delete(match);
      }
    }
  }

  return { isElementAccess, matchProp: search, matches };
}

/**
* @see getMatchedPropsImpl()
*/
function getMatchedPropsInEnvironment(environment, match) {
  return getMatchedPropsImpl(environment, match, DebuggerEnvironmentSupport);
}

/**
* @see getMatchedPropsImpl()
*/
function getMatchedPropsInDbgObject(dbgObject, match) {
  return getMatchedPropsImpl(dbgObject, match, DebuggerObjectSupport);
}

/**
* @see getMatchedPropsImpl()
*/
function getMatchedProps(obj, match) {
  if (typeof obj != "object") {
    obj = obj.constructor.prototype;
  }
  return getMatchedPropsImpl(obj, match, JSObjectSupport);
}

/**
* Get all properties in the given object (and its parent prototype chain) that
* match a given prefix.
*
* @param {Mixed} obj
*        Object whose properties we want to filter.
* @param {string} match
*        Filter for properties that match this string.
* @returns {Set} List of matched properties.
*/
function getMatchedPropsImpl(obj, match, { chainIterator, getProperties }) {
  const matches = new Set();
  let numProps = 0;

  const insensitiveMatching = match && match[0].toUpperCase() !== match[0];
  const propertyMatches = prop => {
    return insensitiveMatching
      ? prop.toLocaleLowerCase().startsWith(match.toLocaleLowerCase())
      : prop.startsWith(match);
  };

  // We need to go up the prototype chain.
  const iter = chainIterator(obj);
  for (obj of iter) {
    const props = getProperties(obj);
    if (!props) {
      continue;
    }
    numProps += props.length;

    // If there are too many properties to event attempt autocompletion,
    // or if we have already added the max number, then stop looping
    // and return the partial set that has already been discovered.
    if (
      numProps >= MAX_AUTOCOMPLETE_ATTEMPTS ||
      matches.size >= MAX_AUTOCOMPLETIONS
    ) {
      break;
    }

    for (let i = 0; i < props.length; i++) {
      const prop = props[i];
      if (!propertyMatches(prop)) {
        continue;
      }

      // If it is an array index, we can't take it.
      // This uses a trick: converting a string to a number yields NaN if
      // the operation failed, and NaN is not equal to itself.
      // eslint-disable-next-line no-self-compare
      if (+prop != +prop || prop === "Infinity") {
        matches.add(prop);
      }

      if (matches.size >= MAX_AUTOCOMPLETIONS) {
        break;
      }
    }
  }

  return matches;
}

/**
* Returns a property value based on its name from the given object, by
* recursively checking the object's prototype.
*
* @param object obj
*        An object to look the property into.
* @param string name
*        The property that is looked up.
* @returns object|undefined
*        A Debugger.Object if the property exists in the object's prototype
*        chain, undefined otherwise.
*/
function getExactMatchImpl(obj, name, { chainIterator, getProperty }) {
  // We need to go up the prototype chain.
  const iter = chainIterator(obj);
  for (obj of iter) {
    const prop = getProperty(obj, name, obj);
    if (prop) {
      return prop.value;
    }
  }
  return undefined;
}

var JSObjectSupport = {
  *chainIterator(obj) {
    while (obj) {
      yield obj;
      try {
        obj = Object.getPrototypeOf(obj);
      } catch (error) {
        // The above can throw e.g. for some proxy objects.
        return;
      }
    }
  },

  getProperties(obj) {
    try {
      return Object.getOwnPropertyNames(obj);
    } catch (error) {
      // The above can throw e.g. for some proxy objects.
      return null;
    }
  },

  getProperty() {
    // getProperty is unsafe with raw JS objects.
    throw new Error("Unimplemented!");
  },
};

var DebuggerObjectSupport = {
  *chainIterator(obj) {
    while (obj) {
      yield obj;
      try {
        // There could be transparent security wrappers, unwrap to check if it's a proxy.
        const unwrapped = DevToolsUtils.unwrap(obj);
        if (unwrapped === undefined) {
          // Objects belonging to an invisible-to-debugger compartment can't be unwrapped.
          return;
        }

        if (unwrapped.isProxy) {
          // Proxies might have a `getPrototypeOf` method, which is triggered by `obj.proto`,
          // but this does not impact the actual prototype chain.
          // In such case, we need to use the proxy target prototype.
          // We retrieve proxyTarget from `obj` (and not `unwrapped`) to avoid exposing
          // the unwrapped target.
          obj = unwrapped.proxyTarget;
        }
        obj = obj.proto;
      } catch (error) {
        // The above can throw e.g. for some proxy objects.
        return;
      }
    }
  },

  getProperties(obj) {
    try {
      return obj.getOwnPropertyNames();
    } catch (error) {
      // The above can throw e.g. for some proxy objects.
      return null;
    }
  },

  getProperty() {
    // This is left unimplemented in favor to DevToolsUtils.getProperty().
    throw new Error("Unimplemented!");
  },
};

var DebuggerEnvironmentSupport = {
  *chainIterator(obj) {
    while (obj) {
      yield obj;
      obj = obj.parent;
    }
  },

  getProperties(obj) {
    const names = obj.names();

    // Include 'this' in results (in sorted order)
    for (let i = 0; i < names.length; i++) {
      if (i === names.length - 1 || names[i + 1] > "this") {
        names.splice(i + 1, 0, "this");
        break;
      }
    }

    return names;
  },

  getProperty(obj, name) {
    let result;
    // Try/catch since name can be anything, and getVariable throws if
    // it's not a valid ECMAScript identifier name
    try {
      // TODO: we should use getVariableDescriptor() here - bug 725815.
      result = obj.getVariable(name);
    } catch (e) {
      // Ignore.
    }

    // FIXME: Need actual UI, bug 941287.
    if (
      result == null ||
      (typeof result == "object" &&
        (result.optimizedOut || result.missingArguments))
    ) {
      return null;
    }
    return { value: result };
  },
};

exports.jsPropertyProvider = DevToolsUtils.makeInfallible(jsPropertyProvider);

// Export a version that will throw (for tests)
exports.fallibleJsPropertyProvider = jsPropertyProvider;

quality89%

¤ Dauer der Verarbeitung: 0.27 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.