Implemented processing of compressed log files.

tools/logreader.js

+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+/**
+ * @fileoverview Log Reader is used to process log file produced by V8.
+ */
+
+// Initlialize namespaces
+var devtools = devtools || {};
+devtools.profiler = devtools.profiler || {};
+
+
+/**
+ * Base class for processing log files.
+ *
+ * @param {Array.<Object>} dispatchTable A table used for parsing and processing
+ *     log records.
+ * @constructor
+ */
+devtools.profiler.LogReader = function(dispatchTable) {
+  /**
+   * @type {Array.<Object>}
+   */
+  this.dispatchTable_ = dispatchTable;
+  this.dispatchTable_['alias'] =
+      { parsers: [null, null], processor: this.processAlias_ };
+  this.dispatchTable_['repeat'] =
+      { parsers: [parseInt, 'var-args'], processor: this.processRepeat_,
+        backrefs: true };
+
+  /**
+   * A key-value map for aliases. Translates short name -> full name.
+   * @type {Object}
+   */
+  this.aliases_ = {};
+
+  /**
+   * A key-value map for previous address values.
+   * @type {Object}
+   */
+  this.prevAddresses_ = {};
+
+  /**
+   * A key-value map for events than can be backreference-compressed.
+   * @type {Object}
+   */
+  this.backRefsCommands_ = {};
+  this.initBackRefsCommands_();
+
+  /**
+   * Back references for decompression.
+   * @type {Array.<string>}
+   */
+  this.backRefs_ = [];
+};
+
+
+/**
+ * Creates a parser for an address entry.
+ *
+ * @param {string} addressTag Address tag to perform offset decoding.
+ * @return {function(string):number} Address parser.
+ */
+devtools.profiler.LogReader.prototype.createAddressParser = function(
+    addressTag) {
+  var self = this;
+  return function addressParser (str) {

[Søren Thygesen Gjesse, 2009/06/18 06:57:44]

Maybe add parentheses arround the function returned 'return (function
addressParser (str) { ... })' - can make it easier to see where it ends. Why
does it have a name anyway?

[Mikhail Naganov, 2009/06/18 07:57:07]

Parentheses added. I thought that giving a name adds clarity, but as it confuses
instead, I've removed it.

+    var value = parseInt(str, 16);
+    var firstChar = str.charAt(0);
+    if (firstChar == '+' || firstChar == '-') {
+      var addr = self.prevAddresses_[addressTag];
+      addr += value;
+      self.prevAddresses_[addressTag] = addr;
+      return addr;
+    } else if (firstChar != '0' || str.charAt(1) != 'x') {
+      self.prevAddresses_[addressTag] = value;
+    }
+    return value;
+  };
+};
+
+
+/**
+ * Expands an alias symbol, if applicable.
+ *
+ * @param {string} symbol Symbol to expand.
+ * @return {string} Expanded symbol, or the input symbol itself.
+ */
+devtools.profiler.LogReader.prototype.expandAlias = function(symbol) {
+  return symbol in this.aliases_ ? this.aliases_[symbol] : symbol;
+};
+
+
+/**
+ * Used for printing error messages.
+ *
+ * @param {string} str Error message.
+ */
+devtools.profiler.LogReader.prototype.printError = function(str) {
+  // Do nothing.
+};
+
+
+/**
+ * Processes a portion of V8 profiler event log.
+ *
+ * @param {string} chunk A portion of log.
+ */
+devtools.profiler.LogReader.prototype.processLogChunk = function(chunk) {
+  this.processLog_(chunk.split('\n'));
+};
+
+
+/**
+ * Processes stack record.
+ *
+ * @param {number} pc Program counter.
+ * @param {Array.<string>} stack String representation of a stack.
+ * @return {Array.<number>} Processed stack.
+ */
+devtools.profiler.LogReader.prototype.processStack = function(pc, stack) {
+  var fullStack = [pc];
+  var prevFrame = pc;
+  for (var i = 0, n = stack.length; i < n; ++i) {
+    var frame = stack[i];
+    var firstChar = frame.charAt(0);
+    if (firstChar == '+' || firstChar == '-') {
+      // An offset from the previous frame.
+      prevFrame += parseInt(frame, 16);
+      fullStack.push(prevFrame);
+    // Filter out possible 'overflow' string.
+    } else if (firstChar != 'o') {
+      fullStack.push(parseInt(frame, 16));
+    }
+  }
+  return fullStack;
+};
+
+
+/**
+ * Returns whether a particular dispatch must be skipped.
+ *
+ * @param {!Object} dispatch Dispatch record.
+ * @return {boolean} True if dispatch must be skipped.
+ */
+devtools.profiler.LogReader.prototype.skipDispatch = function(dispatch) {
+  return false;
+};
+
+
+/**
+ * Does a dispatch of a log record.
+ *
+ * @param {Array.<string>} fields Log record.
+ * @private
+ */
+devtools.profiler.LogReader.prototype.dispatchLogRow_ = function(fields) {
+  // Obtain the dispatch.
+  var command = fields[0];
+  if (!(command in this.dispatchTable_)) {
+    throw new Error('unknown command: ' + command);
+  }
+  var dispatch = this.dispatchTable_[command];
+
+  if (dispatch === null || this.skipDispatch(dispatch)) {
+    return;
+  }
+
+  // Parse fields.
+  var parsedFields = [];
+  for (var i = 0; i < dispatch.parsers.length; ++i) {
+    var parser = dispatch.parsers[i];
+    if (parser === null) {
+      parsedFields.push(fields[1 + i]);
+    } else if (typeof parser == 'function') {
+      parsedFields.push(parser(fields[1 + i]));
+    } else {
+      // var-args
+      parsedFields.push(fields.slice(1 + i));
+      break;
+    }
+  }
+
+  // Run the processor.
+  dispatch.processor.apply(this, parsedFields);
+};
+
+
+/**
+ * Decompresses a line if it was backreference-compressed.
+ *
+ * @param {string} line Possibly compressed line.
+ * @return {string} Decompressed line.
+ * @private
+ */
+devtools.profiler.LogReader.prototype.expandBackRef_ = function(line) {
+  var backRefPos;
+  // Filter out case when a regexp is created containing '#'.
+  if (line.charAt(line.length - 1) != '"'
+      && (backRefPos = line.lastIndexOf('#')) != -1) {
+    var backRef = line.substr(backRefPos + 1);
+    var backRefIdx = parseInt(backRef, 10) - 1;
+    var colonPos = backRef.indexOf(':');
+    var backRefStart =
+        colonPos != -1 ? parseInt(backRef.substr(colonPos + 1), 10) : 0;
+    line = line.substr(0, backRefPos) +
+        this.backRefs_[backRefIdx].substr(backRefStart);
+  }
+  this.backRefs_.unshift(line);
+  if (this.backRefs_.length > 10) {
+    this.backRefs_.length = 10;
+  }
+  return line;
+};
+
+
+/**
+ * Initializes the map of backward reference compressible commands.
+ * @private
+ */
+devtools.profiler.LogReader.prototype.initBackRefsCommands_ = function() {
+  for (var event in this.dispatchTable_) {
+    var dispatch = this.dispatchTable_[event];
+    if (dispatch && dispatch.backrefs) {
+      this.backRefsCommands_[event] = true;
+    }
+  }
+};
+
+
+/**
+ * Processes alias log record. Adds an alias to a corresponding map.
+ *
+ * @param {string} symbol Short name.
+ * @param {string} expansion Long name.
+ * @private
+ */
+devtools.profiler.LogReader.prototype.processAlias_ = function(
+    symbol, expansion) {
+  if (expansion in this.dispatchTable_) {
+    this.dispatchTable_[symbol] = this.dispatchTable_[expansion];
+    if (expansion in this.backRefsCommands_) {
+      this.backRefsCommands_[symbol] = true;
+    }
+  } else {
+    this.aliases_[symbol] = expansion;
+  }
+};
+
+
+/**
+ * Processes log lines.
+ *
+ * @param {Array.<string>} lines Log lines.
+ * @private
+ */
+devtools.profiler.LogReader.prototype.processLog_ = function(lines) {
+  var csvParser = new devtools.profiler.CsvParser();
+  try {
+    for (var i = 0, n = lines.length; i < n; ++i) {
+      var line = lines[i];
+      if (!line) {
+        continue;
+      }
+      if (line.charAt(0) == '#' ||
+          line.substr(0, line.indexOf(',')) in this.backRefsCommands_) {
+        line = this.expandBackRef_(line);
+      }
+      var fields = csvParser.parseLine(line);
+      this.dispatchLogRow_(fields);
+    }
+  } catch (e) {
+    this.printError('line ' + (i + 1) + ': ' + (e.message || e));
+    throw e;
+  }
+};
+
+
+/**
+ * Processes repeat log record. Expands it according to calls count and
+ * invokes processing.
+ *
+ * @param {number} count Count.
+ * @param {Array.<string>} cmd Parsed command.
+ * @private
+ */
+devtools.profiler.LogReader.prototype.processRepeat_ = function(count, cmd) {
+  // Replace the repeat-prefixed command from backrefs list with a non-prefixed.
+  this.backRefs_[0] = cmd.join(',');
+  for (var i = 0; i < count; ++i) {
+    this.dispatchLogRow_(cmd);
+  }
+};