Format in liveedit-debugger.js

src/liveedit-debugger.js

 // Copyright 2010 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
@@ skipping 13 matching lines @@
 // 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.
 
 // LiveEdit feature implementation. The script should be executed after
 // debug-debugger.js.
 
 // A LiveEdit namespace is declared inside a single function constructor.
 Debug.LiveEdit = new function() {
 
-// TODO(LiveEdit): restore indentation below
+  // Changes script text and recompiles all relevant functions if possible.
+  // The change is always a substring (change_pos, change_pos + change_len)
+  // being replaced with a completely different string new_str.
+  //
+  // Only one function will have its Code changed in result of this function.
+  // All nested functions (should they have any instances at the moment) are left
+  // unchanged and re-linked to a newly created script instance representing old
+  // version of the source. (Generally speaking,
+  // during the change all nested functions are erased and completely different
+  // set of nested functions are introduced.) All other functions just have
+  // their positions updated.
+  //
+  // @param {Script} script that is being changed
+  // @param {Array} change_log a list that collects engineer-readable description
+  //     of what happened.
+  function ApplyPatch(script, change_pos, change_len, new_str,
+      change_log) {
+  
+    // Fully compiles source string as a script. Returns Array of
+    // FunctionCompileInfo -- a descriptions of all functions of the script.
+    // Elements of array are ordered by start positions of functions (from top
+    // to bottom) in the source. Fields outer_index and next_sibling_index help
+    // to navigate the nesting structure of functions.
+    //
+    // The script is used for compilation, because it produces code that
+    // needs to be linked with some particular script (for nested functions).
+    function DebugGatherCompileInfo(source) {
+      // Get function info, elements are partially sorted (it is a tree
+      // of nested functions serialized as parent followed by serialized children.
+      var raw_compile_info = %LiveEditGatherCompileInfo(script, source);
+  
+      // Sort function infos by start position field.
+      var compile_info = new Array();
+      var old_index_map = new Array();
+      for (var i = 0; i < raw_compile_info.length; i++) {
+          compile_info.push(new FunctionCompileInfo(raw_compile_info[i]));
+          old_index_map.push(i);
+      }
+  
+      for (var i = 0; i < compile_info.length; i++) {
+        var k = i;
+        for (var j = i + 1; j < compile_info.length; j++) {
+          if (compile_info[k].start_position > compile_info[j].start_position) {
+            k = j;
+          }
+        }
+        if (k != i) {
+          var temp_info = compile_info[k];
+          var temp_index = old_index_map[k];
+          compile_info[k] = compile_info[i];
+          old_index_map[k] = old_index_map[i];
+          compile_info[i] = temp_info;
+          old_index_map[i] = temp_index;
+        }
+      }
+  
+      // After sorting update outer_inder field using old_index_map. Also
+      // set next_sibling_index field.
+      var current_index = 0;
+  
+      // The recursive function, that goes over all children of a particular
+      // node (i.e. function info).
+      function ResetIndexes(new_parent_index, old_parent_index) {
+        var previous_sibling = -1;
+        while (current_index < compile_info.length &&
+            compile_info[current_index].outer_index == old_parent_index) {
+          var saved_index = current_index;
+          compile_info[saved_index].outer_index = new_parent_index;
+          if (previous_sibling != -1) {
+            compile_info[previous_sibling].next_sibling_index = saved_index;
+          }
+          previous_sibling = saved_index;
+          current_index++;
+          ResetIndexes(saved_index, old_index_map[saved_index]);
+        }
+        if (previous_sibling != -1) {
+          compile_info[previous_sibling].next_sibling_index = -1;
+        }
+      }
+  
+      ResetIndexes(-1, -1);
+      Assert(current_index == compile_info.length);
+  
+      return compile_info;
+    }
+  
+    // Given a positions, finds a function that fully includes the entire change.
+    function FindChangedFunction(compile_info, offset, len) {
+      // First condition: function should start before the change region.
+      // Function #0 (whole-script function) always does, but we want
+      // one, that is later in this list.
+      var index = 0;
+      while (index + 1 < compile_info.length &&
+          compile_info[index + 1].start_position <= offset) {
+        index++;
+      }
+      // Now we are at the last function that begins before the change
+      // region. The function that covers entire change region is either
+      // this function or the enclosing one.
+      for (; compile_info[index].end_position < offset + len;
+          index = compile_info[index].outer_index) {
+        Assert(index != -1);
+      }
+      return index;
+    }
+  
+    // Variable forward declarations. Preprocessor "Minifier" needs them.
+    var old_compile_info;
+    var shared_infos;
+    // Finds SharedFunctionInfo that corresponds compile info with index
+    // in old version of the script.
+    function FindFunctionInfo(index) {
+      var old_info = old_compile_info[index];
+      for (var i = 0; i < shared_infos.length; i++) {
+        var info = shared_infos[i];
+        if (info.start_position == old_info.start_position &&
+            info.end_position == old_info.end_position) {
+          return info;
+        }
+      }
+    }
+  
+    // Replaces function's Code.
+    function PatchCode(new_info, shared_info) {
+      %LiveEditReplaceFunctionCode(new_info.raw_array, shared_info.raw_array);
+  
+      change_log.push( {function_patched: new_info.function_name} );
+    }
+  
+    var change_len_old;
+    var change_len_new;
+    // Translate position in old version of script into position in new
+    // version of script.
+    function PosTranslator(old_pos) {
+      if (old_pos <= change_pos) {
+        return old_pos;
+      }
+      if (old_pos >= change_pos + change_len_old) {
+        return old_pos + change_len_new - change_len_old;
+      }
+      return -1;
+    }
+  
+    var position_change_array;
+    var position_patch_report;
+    function PatchPositions(new_info, shared_info) {
+      if (!shared_info) {
+        // TODO(LiveEdit): explain what is happening.
+        return;
+      }
+      var breakpoint_position_update = %LiveEditPatchFunctionPositions(
+          shared_info.raw_array, position_change_array);
+      for (var i = 0; i < breakpoint_position_update.length; i += 2) {
+        var new_pos = breakpoint_position_update[i];
+        var break_point_object = breakpoint_position_update[i + 1];
+        change_log.push( { breakpoint_position_update:
+            { from: break_point_object.source_position(), to: new_pos } } );
+        break_point_object.updateSourcePosition(new_pos, script);
+      }
+      position_patch_report.push( { name: new_info.function_name } );
+    }
+  
+    var link_to_old_script_report;
+    var old_script;
+    // Makes a function associated with another instance of a script (the
+    // one representing its old version). This way the function still
+    // may access its own text.
+    function LinkToOldScript(shared_info) {
+      %LiveEditRelinkFunctionToScript(shared_info.raw_array, old_script);
+  
+      link_to_old_script_report.push( { name: shared_info.function_name } );
+    }
+  
+  
+  
+    var old_source = script.source;
+    var change_len_old = change_len;
+    var change_len_new = new_str.length;
+  
+    // Prepare new source string.
+    var new_source = old_source.substring(0, change_pos) +
+        new_str + old_source.substring(change_pos + change_len);
+  
+    // Find all SharedFunctionInfo's that are compiled from this script.
+    var shared_raw_list = %LiveEditFindSharedFunctionInfosForScript(script);
+  
+    var shared_infos = new Array();
+  
+    for (var i = 0; i < shared_raw_list.length; i++) {
+      shared_infos.push(new SharedInfoWrapper(shared_raw_list[i]));
+    }
+  
+    // Gather compile information about old version of script.
+    var old_compile_info = DebugGatherCompileInfo(old_source);
+  
+    // Gather compile information about new version of script.
+    var new_compile_info;
+    try {
+      new_compile_info = DebugGatherCompileInfo(new_source);
+    } catch (e) {
+      throw new Failure("Failed to compile new version of script: " + e);
+    }
+  
+    // An index of a single function, that is going to have its code replaced.
+    var function_being_patched =
+        FindChangedFunction(old_compile_info, change_pos, change_len_old);
+  
+    // In old and new script versions function with a change should have the
+    // same indexes.
+    var function_being_patched2 =
+        FindChangedFunction(new_compile_info, change_pos, change_len_new);
+    Assert(function_being_patched == function_being_patched2,
+           "inconsistent old/new compile info");
+  
+    // Check that function being patched has the same expectations in a new
+    // version. Otherwise we cannot safely patch its behavior and should
+    // choose the outer function instead.
+    while (!CompareFunctionExpectations(
+        old_compile_info[function_being_patched],
+        new_compile_info[function_being_patched])) {
+  
+      Assert(old_compile_info[function_being_patched].outer_index ==
+          new_compile_info[function_being_patched].outer_index);
+      function_being_patched =
+          old_compile_info[function_being_patched].outer_index;
+      Assert(function_being_patched != -1);
+    }
+  
+    // Check that function being patched is not currently on stack.
+    CheckStackActivations(
+        [ FindFunctionInfo(function_being_patched) ], change_log );
+  
+  
+    // Committing all changes.
+    var old_script_name = CreateNameForOldScript(script);
+  
+    // Update the script text and create a new script representing an old
+    // version of the script.
+    var old_script = %LiveEditReplaceScript(script, new_source, old_script_name);
+  
+    PatchCode(new_compile_info[function_being_patched],
+        FindFunctionInfo(function_being_patched));
+  
+    var position_patch_report = new Array();
+    change_log.push( {position_patched: position_patch_report} );
+  
+    var position_change_array = [ change_pos,
+                                  change_pos + change_len_old,
+                                  change_pos + change_len_new ];
+  
+    // Update positions of all outer functions (i.e. all functions, that
+    // are partially below the function being patched).
+    for (var i = new_compile_info[function_being_patched].outer_index;
+        i != -1;
+        i = new_compile_info[i].outer_index) {
+      PatchPositions(new_compile_info[i], FindFunctionInfo(i));
+    }
+  
+    // Update positions of all functions that are fully below the function
+    // being patched.
+    var old_next_sibling =
+        old_compile_info[function_being_patched].next_sibling_index;
+    var new_next_sibling =
+        new_compile_info[function_being_patched].next_sibling_index;
+  
+    // We simply go over the tail of both old and new lists. Their tails should
+    // have an identical structure.
+    if (old_next_sibling == -1) {
+      Assert(new_next_sibling == -1);
+    } else {
+      Assert(old_compile_info.length - old_next_sibling ==
+          new_compile_info.length - new_next_sibling);
+  
+      for (var i = old_next_sibling, j = new_next_sibling;
+          i < old_compile_info.length; i++, j++) {
+        PatchPositions(new_compile_info[j], FindFunctionInfo(i));
+      }
+    }
+  
+    var link_to_old_script_report = new Array();
+    change_log.push( { linked_to_old_script: link_to_old_script_report } );
+  
+    // We need to link to old script all former nested functions.
+    for (var i = function_being_patched + 1; i < old_next_sibling; i++) {
+      LinkToOldScript(FindFunctionInfo(i), old_script);
+    }
+  }
+  // Function is public.
+  this.ApplyPatch = ApplyPatch;
+  
+  function Assert(condition, message) {
+    if (!condition) {
+      if (message) {
+        throw "Assert " + message;
+      } else {
+        throw "Assert";
+      }
+    }
+  }
+  
+  // An object describing function compilation details. Its index fields
+  // apply to indexes inside array that stores these objects.
+  function FunctionCompileInfo(raw_array) {
+    this.function_name = raw_array[0];
+    this.start_position = raw_array[1];
+    this.end_position = raw_array[2];
+    this.param_num = raw_array[3];
+    this.code = raw_array[4];
+    this.scope_info = raw_array[5];
+    this.outer_index = raw_array[6];
+    this.next_sibling_index = null;
+    this.raw_array = raw_array;
+  }
+  
+  function SharedInfoWrapper(raw_array) {
+    this.function_name = raw_array[0];
+    this.start_position = raw_array[1];
+    this.end_position = raw_array[2];
+    this.info = raw_array[3];
+    this.raw_array = raw_array;
+  }
+  
+  // Adds a suffix to script name to mark that it is old version.
+  function CreateNameForOldScript(script) {
+    // TODO(635): try better than this; support several changes.
+    return script.name + " (old)";
+  }
+  
+  // Compares a function interface old and new version, whether it
+  // changed or not.
+  function CompareFunctionExpectations(function_info1, function_info2) {
+    // Check that function has the same number of parameters (there may exist
+    // an adapter, that won't survive function parameter number change).
+    if (function_info1.param_num != function_info2.param_num) {
+      return false;
+    }
+    var scope_info1 = function_info1.scope_info;
+    var scope_info2 = function_info2.scope_info;
+  
+    if (!scope_info1) {
+      return !scope_info2;
+    }
+  
+    if (scope_info1.length != scope_info2.length) {
+      return false;
+    }
+  
+    // Check that outer scope structure is not changed. Otherwise the function
+    // will not properly work with existing scopes.
+    return scope_info1.toString() == scope_info2.toString();
+  }
+  
+  // Minifier forward declaration.
+  var FunctionPatchabilityStatus;
+  
+  // For array of wrapped shared function infos checks that none of them
+  // have activations on stack (of any thread). Throws a Failure exception
+  // if this proves to be false.
+  function CheckStackActivations(shared_wrapper_list, change_log) {
+    var shared_list = new Array();
+    for (var i = 0; i < shared_wrapper_list.length; i++) {
+      shared_list[i] = shared_wrapper_list[i].info;
+    }
+    var result = %LiveEditCheckAndDropActivations(shared_list, true);
+    if (result[shared_list.length]) {
+      // Extra array element may contain error message.
+      throw new Failure(result[shared_list.length]);
+    }
+  
+    var problems = new Array();
+    var dropped = new Array();
+    for (var i = 0; i < shared_list.length; i++) {
+      var shared = shared_wrapper_list[i];
+      if (result[i] == FunctionPatchabilityStatus.REPLACED_ON_ACTIVE_STACK) {
+        dropped.push({ name: shared.function_name } );
+      } else if (result[i] != FunctionPatchabilityStatus.AVAILABLE_FOR_PATCH) {
+        var description = {
+            name: shared.function_name,
+            start_pos: shared.start_position, 
+            end_pos: shared.end_position,
+            replace_problem:
+                FunctionPatchabilityStatus.SymbolName(result[i])
+        };
+        problems.push(description);
+      }
+    }
+    if (dropped.length > 0) {
+      change_log.push({ dropped_from_stack: dropped });
+    }
+    if (problems.length > 0) {
+      change_log.push( { functions_on_stack: problems } );
+      throw new Failure("Blocked by functions on stack");
+    }
+  }
+  
+  // A copy of the FunctionPatchabilityStatus enum from liveedit.h
+  var FunctionPatchabilityStatus = {
+      AVAILABLE_FOR_PATCH: 1,
+      BLOCKED_ON_ACTIVE_STACK: 2,
+      BLOCKED_ON_OTHER_STACK: 3,
+      BLOCKED_UNDER_NATIVE_CODE: 4,
+      REPLACED_ON_ACTIVE_STACK: 5
+  }
+  
+  FunctionPatchabilityStatus.SymbolName = function(code) {
+    var enum = FunctionPatchabilityStatus;
+    for (name in enum) {
+      if (enum[name] == code) {
+        return name;
+      }
+    }      
+  }
+  
+  
+  // A logical failure in liveedit process. This means that change_log
+  // is valid and consistent description of what happened.
+  function Failure(message) {
+    this.message = message;
+  }
+  // Function (constructor) is public.
+  this.Failure = Failure;
+  
+  Failure.prototype.toString = function() {
+    return "LiveEdit Failure: " + this.message;
+  }
+  
+  // A testing entry.
+  function GetPcFromSourcePos(func, source_pos) {
+    return %GetFunctionCodePositionFromSource(func, source_pos);
+  }
+  // Function is public.
+  this.GetPcFromSourcePos = GetPcFromSourcePos;
 
-// Changes script text and recompiles all relevant functions if possible.
-// The change is always a substring (change_pos, change_pos + change_len)
-// being replaced with a completely different string new_str.
-//
-// Only one function will have its Code changed in result of this function.
-// All nested functions (should they have any instances at the moment) are left
-// unchanged and re-linked to a newly created script instance representing old
-// version of the source. (Generally speaking,
-// during the change all nested functions are erased and completely different
-// set of nested functions are introduced.) All other functions just have
-// their positions updated.
-//
-// @param {Script} script that is being changed
-// @param {Array} change_log a list that collects engineer-readable description
-//     of what happened.
-function ApplyPatch(script, change_pos, change_len, new_str,
-    change_log) {
-
-  // Fully compiles source string as a script. Returns Array of
-  // FunctionCompileInfo -- a descriptions of all functions of the script.
-  // Elements of array are ordered by start positions of functions (from top
-  // to bottom) in the source. Fields outer_index and next_sibling_index help
-  // to navigate the nesting structure of functions.
-  //
-  // The script is used for compilation, because it produces code that
-  // needs to be linked with some particular script (for nested functions).
-  function DebugGatherCompileInfo(source) {
-    // Get function info, elements are partially sorted (it is a tree
-    // of nested functions serialized as parent followed by serialized children.
-    var raw_compile_info = %LiveEditGatherCompileInfo(script, source);
-
-    // Sort function infos by start position field.
-    var compile_info = new Array();
-    var old_index_map = new Array();
-    for (var i = 0; i < raw_compile_info.length; i++) {
-        compile_info.push(new FunctionCompileInfo(raw_compile_info[i]));
-        old_index_map.push(i);
-    }
-
-    for (var i = 0; i < compile_info.length; i++) {
-      var k = i;
-      for (var j = i + 1; j < compile_info.length; j++) {
-        if (compile_info[k].start_position > compile_info[j].start_position) {
-          k = j;
-        }
-      }
-      if (k != i) {
-        var temp_info = compile_info[k];
-        var temp_index = old_index_map[k];
-        compile_info[k] = compile_info[i];
-        old_index_map[k] = old_index_map[i];
-        compile_info[i] = temp_info;
-        old_index_map[i] = temp_index;
-      }
-    }
-
-    // After sorting update outer_inder field using old_index_map. Also
-    // set next_sibling_index field.
-    var current_index = 0;
-
-    // The recursive function, that goes over all children of a particular
-    // node (i.e. function info).
-    function ResetIndexes(new_parent_index, old_parent_index) {
-      var previous_sibling = -1;
-      while (current_index < compile_info.length &&
-          compile_info[current_index].outer_index == old_parent_index) {
-        var saved_index = current_index;
-        compile_info[saved_index].outer_index = new_parent_index;
-        if (previous_sibling != -1) {
-          compile_info[previous_sibling].next_sibling_index = saved_index;
-        }
-        previous_sibling = saved_index;
-        current_index++;
-        ResetIndexes(saved_index, old_index_map[saved_index]);
-      }
-      if (previous_sibling != -1) {
-        compile_info[previous_sibling].next_sibling_index = -1;
-      }
-    }
-
-    ResetIndexes(-1, -1);
-    Assert(current_index == compile_info.length);
-
-    return compile_info;
-  }
-
-  // Given a positions, finds a function that fully includes the entire change.
-  function FindChangedFunction(compile_info, offset, len) {
-    // First condition: function should start before the change region.
-    // Function #0 (whole-script function) always does, but we want
-    // one, that is later in this list.
-    var index = 0;
-    while (index + 1 < compile_info.length &&
-        compile_info[index + 1].start_position <= offset) {
-      index++;
-    }
-    // Now we are at the last function that begins before the change
-    // region. The function that covers entire change region is either
-    // this function or the enclosing one.
-    for (; compile_info[index].end_position < offset + len;
-        index = compile_info[index].outer_index) {
-      Assert(index != -1);
-    }
-    return index;
-  }
-
-  // Variable forward declarations. Preprocessor "Minifier" needs them.
-  var old_compile_info;
-  var shared_infos;
-  // Finds SharedFunctionInfo that corresponds compile info with index
-  // in old version of the script.
-  function FindFunctionInfo(index) {
-    var old_info = old_compile_info[index];
-    for (var i = 0; i < shared_infos.length; i++) {
-      var info = shared_infos[i];
-      if (info.start_position == old_info.start_position &&
-          info.end_position == old_info.end_position) {
-        return info;
-      }
-    }
-  }
-
-  // Replaces function's Code.
-  function PatchCode(new_info, shared_info) {
-    %LiveEditReplaceFunctionCode(new_info.raw_array, shared_info.raw_array);
-
-    change_log.push( {function_patched: new_info.function_name} );
-  }
-
-  var change_len_old;
-  var change_len_new;
-  // Translate position in old version of script into position in new
-  // version of script.
-  function PosTranslator(old_pos) {
-    if (old_pos <= change_pos) {
-      return old_pos;
-    }
-    if (old_pos >= change_pos + change_len_old) {
-      return old_pos + change_len_new - change_len_old;
-    }
-    return -1;
-  }
-
-  var position_change_array;
-  var position_patch_report;
-  function PatchPositions(new_info, shared_info) {
-    if (!shared_info) {
-      // TODO(LiveEdit): explain what is happening.
-      return;
-    }
-    var breakpoint_position_update = %LiveEditPatchFunctionPositions(
-        shared_info.raw_array, position_change_array);
-    for (var i = 0; i < breakpoint_position_update.length; i += 2) {
-      var new_pos = breakpoint_position_update[i];
-      var break_point_object = breakpoint_position_update[i + 1];
-      change_log.push( { breakpoint_position_update:
-          { from: break_point_object.source_position(), to: new_pos } } );
-      break_point_object.updateSourcePosition(new_pos, script);
-    }
-    position_patch_report.push( { name: new_info.function_name } );
-  }
-
-  var link_to_old_script_report;
-  var old_script;
-  // Makes a function associated with another instance of a script (the
-  // one representing its old version). This way the function still
-  // may access its own text.
-  function LinkToOldScript(shared_info) {
-    %LiveEditRelinkFunctionToScript(shared_info.raw_array, old_script);
-
-    link_to_old_script_report.push( { name: shared_info.function_name } );
-  }
-
-
-
-  var old_source = script.source;
-  var change_len_old = change_len;
-  var change_len_new = new_str.length;
-
-  // Prepare new source string.
-  var new_source = old_source.substring(0, change_pos) +
-      new_str + old_source.substring(change_pos + change_len);
-
-  // Find all SharedFunctionInfo's that are compiled from this script.
-  var shared_raw_list = %LiveEditFindSharedFunctionInfosForScript(script);
-
-  var shared_infos = new Array();
-
-  for (var i = 0; i < shared_raw_list.length; i++) {
-    shared_infos.push(new SharedInfoWrapper(shared_raw_list[i]));
-  }
-
-  // Gather compile information about old version of script.
-  var old_compile_info = DebugGatherCompileInfo(old_source);
-
-  // Gather compile information about new version of script.
-  var new_compile_info;
-  try {
-    new_compile_info = DebugGatherCompileInfo(new_source);
-  } catch (e) {
-    throw new Failure("Failed to compile new version of script: " + e);
-  }
-
-  // An index of a single function, that is going to have its code replaced.
-  var function_being_patched =
-      FindChangedFunction(old_compile_info, change_pos, change_len_old);
-
-  // In old and new script versions function with a change should have the
-  // same indexes.
-  var function_being_patched2 =
-      FindChangedFunction(new_compile_info, change_pos, change_len_new);
-  Assert(function_being_patched == function_being_patched2,
-         "inconsistent old/new compile info");
-
-  // Check that function being patched has the same expectations in a new
-  // version. Otherwise we cannot safely patch its behavior and should
-  // choose the outer function instead.
-  while (!CompareFunctionExpectations(
-      old_compile_info[function_being_patched],
-      new_compile_info[function_being_patched])) {
-
-    Assert(old_compile_info[function_being_patched].outer_index ==
-        new_compile_info[function_being_patched].outer_index);
-    function_being_patched =
-        old_compile_info[function_being_patched].outer_index;
-    Assert(function_being_patched != -1);
-  }
-
-  // Check that function being patched is not currently on stack.
-  CheckStackActivations(
-      [ FindFunctionInfo(function_being_patched) ], change_log );
-
-
-  // Committing all changes.
-  var old_script_name = CreateNameForOldScript(script);
-
-  // Update the script text and create a new script representing an old
-  // version of the script.
-  var old_script = %LiveEditReplaceScript(script, new_source, old_script_name);
-
-  PatchCode(new_compile_info[function_being_patched],
-      FindFunctionInfo(function_being_patched));
-
-  var position_patch_report = new Array();
-  change_log.push( {position_patched: position_patch_report} );
-
-  var position_change_array = [ change_pos,
-                                change_pos + change_len_old,
-                                change_pos + change_len_new ];
-
-  // Update positions of all outer functions (i.e. all functions, that
-  // are partially below the function being patched).
-  for (var i = new_compile_info[function_being_patched].outer_index;
-      i != -1;
-      i = new_compile_info[i].outer_index) {
-    PatchPositions(new_compile_info[i], FindFunctionInfo(i));
-  }
-
-  // Update positions of all functions that are fully below the function
-  // being patched.
-  var old_next_sibling =
-      old_compile_info[function_being_patched].next_sibling_index;
-  var new_next_sibling =
-      new_compile_info[function_being_patched].next_sibling_index;
-
-  // We simply go over the tail of both old and new lists. Their tails should
-  // have an identical structure.
-  if (old_next_sibling == -1) {
-    Assert(new_next_sibling == -1);
-  } else {
-    Assert(old_compile_info.length - old_next_sibling ==
-        new_compile_info.length - new_next_sibling);
-
-    for (var i = old_next_sibling, j = new_next_sibling;
-        i < old_compile_info.length; i++, j++) {
-      PatchPositions(new_compile_info[j], FindFunctionInfo(i));
-    }
-  }
-
-  var link_to_old_script_report = new Array();
-  change_log.push( { linked_to_old_script: link_to_old_script_report } );
-
-  // We need to link to old script all former nested functions.
-  for (var i = function_being_patched + 1; i < old_next_sibling; i++) {
-    LinkToOldScript(FindFunctionInfo(i), old_script);
-  }
-}
-// Function is public.
-this.ApplyPatch = ApplyPatch;
-
-function Assert(condition, message) {
-  if (!condition) {
-    if (message) {
-      throw "Assert " + message;
-    } else {
-      throw "Assert";
-    }
-  }
-}
-
-// An object describing function compilation details. Its index fields
-// apply to indexes inside array that stores these objects.
-function FunctionCompileInfo(raw_array) {
-  this.function_name = raw_array[0];
-  this.start_position = raw_array[1];
-  this.end_position = raw_array[2];
-  this.param_num = raw_array[3];
-  this.code = raw_array[4];
-  this.scope_info = raw_array[5];
-  this.outer_index = raw_array[6];
-  this.next_sibling_index = null;
-  this.raw_array = raw_array;
-}
-
-function SharedInfoWrapper(raw_array) {
-  this.function_name = raw_array[0];
-  this.start_position = raw_array[1];
-  this.end_position = raw_array[2];
-  this.info = raw_array[3];
-  this.raw_array = raw_array;
-}
-
-// Adds a suffix to script name to mark that it is old version.
-function CreateNameForOldScript(script) {
-  // TODO(635): try better than this; support several changes.
-  return script.name + " (old)";
-}
-
-// Compares a function interface old and new version, whether it
-// changed or not.
-function CompareFunctionExpectations(function_info1, function_info2) {
-  // Check that function has the same number of parameters (there may exist
-  // an adapter, that won't survive function parameter number change).
-  if (function_info1.param_num != function_info2.param_num) {
-    return false;
-  }
-  var scope_info1 = function_info1.scope_info;
-  var scope_info2 = function_info2.scope_info;
-
-  if (!scope_info1) {
-    return !scope_info2;
-  }
-
-  if (scope_info1.length != scope_info2.length) {
-    return false;
-  }
-
-  // Check that outer scope structure is not changed. Otherwise the function
-  // will not properly work with existing scopes.
-  return scope_info1.toString() == scope_info2.toString();
-}
-
-// Minifier forward declaration.
-var FunctionPatchabilityStatus;
-
-// For array of wrapped shared function infos checks that none of them
-// have activations on stack (of any thread). Throws a Failure exception
-// if this proves to be false.
-function CheckStackActivations(shared_wrapper_list, change_log) {
-  var shared_list = new Array();
-  for (var i = 0; i < shared_wrapper_list.length; i++) {
-    shared_list[i] = shared_wrapper_list[i].info;
-  }
-  var result = %LiveEditCheckAndDropActivations(shared_list, true);
-  if (result[shared_list.length]) {
-    // Extra array element may contain error message.
-    throw new Failure(result[shared_list.length]);
-  }
-
-  var problems = new Array();
-  var dropped = new Array();
-  for (var i = 0; i < shared_list.length; i++) {
-    var shared = shared_wrapper_list[i];
-    if (result[i] == FunctionPatchabilityStatus.REPLACED_ON_ACTIVE_STACK) {
-      dropped.push({ name: shared.function_name } );
-    } else if (result[i] != FunctionPatchabilityStatus.AVAILABLE_FOR_PATCH) {
-      var description = {
-          name: shared.function_name,
-          start_pos: shared.start_position, 
-          end_pos: shared.end_position,
-          replace_problem:
-              FunctionPatchabilityStatus.SymbolName(result[i])
-      };
-      problems.push(description);
-    }
-  }
-  if (dropped.length > 0) {
-    change_log.push({ dropped_from_stack: dropped });
-  }
-  if (problems.length > 0) {
-    change_log.push( { functions_on_stack: problems } );
-    throw new Failure("Blocked by functions on stack");
-  }
-}
-
-// A copy of the FunctionPatchabilityStatus enum from liveedit.h
-var FunctionPatchabilityStatus = {
-    AVAILABLE_FOR_PATCH: 1,
-    BLOCKED_ON_ACTIVE_STACK: 2,
-    BLOCKED_ON_OTHER_STACK: 3,
-    BLOCKED_UNDER_NATIVE_CODE: 4,
-    REPLACED_ON_ACTIVE_STACK: 5
-}
-
-FunctionPatchabilityStatus.SymbolName = function(code) {
-  var enum = FunctionPatchabilityStatus;
-  for (name in enum) {
-    if (enum[name] == code) {
-      return name;
-    }
-  }      
-}
-
-
-// A logical failure in liveedit process. This means that change_log
-// is valid and consistent description of what happened.
-function Failure(message) {
-  this.message = message;
-}
-// Function (constructor) is public.
-this.Failure = Failure;
-
-Failure.prototype.toString = function() {
-  return "LiveEdit Failure: " + this.message;
-}
-
-// A testing entry.
-function GetPcFromSourcePos(func, source_pos) {
-  return %GetFunctionCodePositionFromSource(func, source_pos);
-}
-// Function is public.
-this.GetPcFromSourcePos = GetPcFromSourcePos;
-
-// TODO(LiveEdit): restore indentation above
-  
   // LiveEdit main entry point: changes a script text to a new string.
   function SetScriptSource(script, new_source, change_log) {
     var old_source = script.source;
     var diff = FindSimpleDiff(old_source, new_source);
     if (!diff) {
       return;
     }
     ApplyPatch(script, diff.change_pos, diff.old_len,
         new_source.substring(diff.change_pos, diff.change_pos + diff.new_len),
         change_log);
@@ skipping 59 matching lines @@
     }
 
     if (old_len == 0 && new_len == 0) {
       // no change
       return;
     }
     
     return { "change_pos": change_pos, "old_len": old_len, "new_len": new_len };
   }
 }