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Name	Size	Last Modified	Actions
[F]apply.js Edit	9.05 KB	2022-10-08 17:28:24
[F]index.js Edit	3.05 KB	2022-10-08 17:28:24

Editing: apply.js

import { encodeNode } from "@webassemblyjs/wasm-gen";
import { encodeU32 } from "@webassemblyjs/wasm-gen/lib/encoder";
import { isFunc, isGlobal, assertHasLoc, orderedInsertNode, getSectionMetadata, traverse, getEndOfSection } from "@webassemblyjs/ast";
import { resizeSectionByteSize, resizeSectionVecSize, createEmptySection, removeSections } from "@webassemblyjs/helper-wasm-section";
import { overrideBytesInBuffer } from "@webassemblyjs/helper-buffer";
import { getSectionForNode } from "@webassemblyjs/helper-wasm-bytecode";

function shiftLocNodeByDelta(node, delta) {
  assertHasLoc(node); // $FlowIgnore: assertHasLoc ensures that

node.loc.start.column += delta; // $FlowIgnore: assertHasLoc ensures that

node.loc.end.column += delta;
}

function applyUpdate(ast, uint8Buffer, _ref) {
  var _ref2 = _slicedToArray(_ref, 2),
      oldNode = _ref2[0],
      newNode = _ref2[1];

var deltaElements = 0;
  assertHasLoc(oldNode);
  var sectionName = getSectionForNode(newNode);
  var replacementByteArray = encodeNode(newNode);
  /**
   * Replace new node as bytes
   */

uint8Buffer = overrideBytesInBuffer(uint8Buffer, // $FlowIgnore: assertHasLoc ensures that
  oldNode.loc.start.column, // $FlowIgnore: assertHasLoc ensures that
  oldNode.loc.end.column, replacementByteArray);
  /**
   * Update function body size if needed
   */

if (sectionName === "code") {
    // Find the parent func
    traverse(ast, {
      Func: function Func(_ref3) {
        var node = _ref3.node;
        var funcHasThisIntr = node.body.find(function (n) {
          return n === newNode;
        }) !== undefined; // Update func's body size if needed

if (funcHasThisIntr === true) {
          // These are the old functions locations informations
          assertHasLoc(node);
          var oldNodeSize = encodeNode(oldNode).length;
          var bodySizeDeltaBytes = replacementByteArray.length - oldNodeSize;

if (bodySizeDeltaBytes !== 0) {
            var newValue = node.metadata.bodySize + bodySizeDeltaBytes;
            var newByteArray = encodeU32(newValue); // function body size byte
            // FIXME(sven): only handles one byte u32

var start = node.loc.start.column;
            var end = start + 1;
            uint8Buffer = overrideBytesInBuffer(uint8Buffer, start, end, newByteArray);
          }
        }
      }
    });
  }
  /**
   * Update section size
   */

var deltaBytes = replacementByteArray.length - ( // $FlowIgnore: assertHasLoc ensures that
  oldNode.loc.end.column - oldNode.loc.start.column); // Init location informations

newNode.loc = {
    start: {
      line: -1,
      column: -1
    },
    end: {
      line: -1,
      column: -1
    }
  }; // Update new node end position
  // $FlowIgnore: assertHasLoc ensures that

newNode.loc.start.column = oldNode.loc.start.column; // $FlowIgnore: assertHasLoc ensures that

newNode.loc.end.column = // $FlowIgnore: assertHasLoc ensures that
  oldNode.loc.start.column + replacementByteArray.length;
  return {
    uint8Buffer: uint8Buffer,
    deltaBytes: deltaBytes,
    deltaElements: deltaElements
  };
}

function applyDelete(ast, uint8Buffer, node) {
  var deltaElements = -1; // since we removed an element

assertHasLoc(node);
  var sectionName = getSectionForNode(node);

if (sectionName === "start") {
    var sectionMetadata = getSectionMetadata(ast, "start");
    /**
     * The start section only contains one element,
     * we need to remove the whole section
     */

uint8Buffer = removeSections(ast, uint8Buffer, "start");

var _deltaBytes = -(sectionMetadata.size.value + 1);
    /* section id */

return {
      uint8Buffer: uint8Buffer,
      deltaBytes: _deltaBytes,
      deltaElements: deltaElements
    };
  } // replacement is nothing

var replacement = [];
  uint8Buffer = overrideBytesInBuffer(uint8Buffer, // $FlowIgnore: assertHasLoc ensures that
  node.loc.start.column, // $FlowIgnore: assertHasLoc ensures that
  node.loc.end.column, replacement);
  /**
   * Update section
   */
  // $FlowIgnore: assertHasLoc ensures that

var deltaBytes = -(node.loc.end.column - node.loc.start.column);
  return {
    uint8Buffer: uint8Buffer,
    deltaBytes: deltaBytes,
    deltaElements: deltaElements
  };
}

function applyAdd(ast, uint8Buffer, node) {
  var deltaElements = +1; // since we added an element

var sectionName = getSectionForNode(node);
  var sectionMetadata = getSectionMetadata(ast, sectionName); // Section doesn't exists, we create an empty one

if (typeof sectionMetadata === "undefined") {
    var res = createEmptySection(ast, uint8Buffer, sectionName);
    uint8Buffer = res.uint8Buffer;
    sectionMetadata = res.sectionMetadata;
  }
  /**
   * check that the expressions were ended
   */

if (isFunc(node)) {
    // $FlowIgnore
    var body = node.body;

if (body.length === 0 || body[body.length - 1].id !== "end") {
      throw new Error("expressions must be ended");
    }
  }

if (isGlobal(node)) {
    // $FlowIgnore
    var body = node.init;

if (body.length === 0 || body[body.length - 1].id !== "end") {
      throw new Error("expressions must be ended");
    }
  }
  /**
   * Add nodes
   */

var newByteArray = encodeNode(node); // The size of the section doesn't include the storage of the size itself
  // we need to manually add it here

var start = getEndOfSection(sectionMetadata);
  var end = start;
  /**
   * Update section
   */

if (node.type === "Func") {
    // the size is the first byte
    // FIXME(sven): handle LEB128 correctly here
    var bodySize = newByteArray[0];
    node.metadata = {
      bodySize: bodySize
    };
  }

if (node.type !== "IndexInFuncSection") {
    orderedInsertNode(ast.body[0], node);
  }

return {
    uint8Buffer: uint8Buffer,
    deltaBytes: deltaBytes,
    deltaElements: deltaElements
  };
}

export function applyOperations(ast, uint8Buffer, ops) {
  ops.forEach(function (op) {
    var state;
    var sectionName;

switch (op.kind) {
      case "update":
        state = applyUpdate(ast, uint8Buffer, [op.oldNode, op.node]);
        sectionName = getSectionForNode(op.node);
        break;

case "delete":
        state = applyDelete(ast, uint8Buffer, op.node);
        sectionName = getSectionForNode(op.node);
        break;

case "add":
        state = applyAdd(ast, uint8Buffer, op.node);
        sectionName = getSectionForNode(op.node);
        break;

default:
        throw new Error("Unknown operation");
    }
    /**
     * Resize section vec size.
     * If the length of the LEB-encoded size changes, this can change
     * the byte length of the section and the offset for nodes in the
     * section. So we do this first before resizing section byte size
     * or shifting following operations' nodes.
     */

if (state.deltaElements !== 0 && sectionName !== "start") {
      var oldBufferLength = state.uint8Buffer.length;
      state.uint8Buffer = resizeSectionVecSize(ast, state.uint8Buffer, sectionName, state.deltaElements); // Infer bytes added/removed by comparing buffer lengths

state.deltaBytes += state.uint8Buffer.length - oldBufferLength;
    }
    /**
     * Resize section byte size.
     * If the length of the LEB-encoded size changes, this can change
     * the offset for nodes in the section. So we do this before
     * shifting following operations' nodes.
     */

if (state.deltaBytes !== 0 && sectionName !== "start") {
      var _oldBufferLength = state.uint8Buffer.length;
      state.uint8Buffer = resizeSectionByteSize(ast, state.uint8Buffer, sectionName, state.deltaBytes); // Infer bytes added/removed by comparing buffer lengths

state.deltaBytes += state.uint8Buffer.length - _oldBufferLength;
    }
    /**
     * Shift following operation's nodes
     */

if (state.deltaBytes !== 0) {
      ops.forEach(function (op) {
        // We don't need to handle add ops, they are positioning independent
        switch (op.kind) {
          case "update":
            shiftLocNodeByDelta(op.oldNode, state.deltaBytes);
            break;

case "delete":
            shiftLocNodeByDelta(op.node, state.deltaBytes);
            break;
        }
      });
    }

uint8Buffer = state.uint8Buffer;
  });
  return uint8Buffer;
}

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