v8/src/liveedit-debugger.js

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// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// LiveEdit feature implementation. The script should be executed after
// debug-debugger.js.
// A LiveEdit namespace. It contains functions that modifies JavaScript code
// according to changes of script source (if possible).
//
// When new script source is put in, the difference is calculated textually,
// in form of list of delete/add/change chunks. The functions that include
// change chunk(s) get recompiled, or their enclosing functions are
// recompiled instead.
// If the function may not be recompiled (e.g. it was completely erased in new
// version of the script) it remains unchanged, but the code that could
// create a new instance of this function goes away. An old version of script
// is created to back up this obsolete function.
// All unchanged functions have their positions updated accordingly.
//
// LiveEdit namespace is declared inside a single function constructor.
"use strict";
Debug.LiveEdit = new function() {
// Forward declaration for minifier.
var FunctionStatus;
var NEEDS_STEP_IN_PROPERTY_NAME = "stack_update_needs_step_in";
// Applies the change to the script.
// The change is in form of list of chunks encoded in a single array as
// a series of triplets (pos1_start, pos1_end, pos2_end)
function ApplyPatchMultiChunk(script, diff_array, new_source, preview_only,
change_log) {
var old_source = script.source;
// Gather compile information about old version of script.
var old_compile_info = GatherCompileInfo(old_source, script);
// Build tree structures for old and new versions of the script.
var root_old_node = BuildCodeInfoTree(old_compile_info);
var pos_translator = new PosTranslator(diff_array);
// Analyze changes.
MarkChangedFunctions(root_old_node, pos_translator.GetChunks());
// Find all SharedFunctionInfo's that were compiled from this script.
FindLiveSharedInfos(root_old_node, script);
// Gather compile information about new version of script.
var new_compile_info;
try {
new_compile_info = GatherCompileInfo(new_source, script);
} catch (e) {
var failure =
new Failure("Failed to compile new version of script: " + e);
if (e instanceof SyntaxError) {
var details = {
type: "liveedit_compile_error",
syntaxErrorMessage: e.message
};
CopyErrorPositionToDetails(e, details);
failure.details = details;
}
throw failure;
}
var root_new_node = BuildCodeInfoTree(new_compile_info);
// Link recompiled script data with other data.
FindCorrespondingFunctions(root_old_node, root_new_node);
// Prepare to-do lists.
var replace_code_list = new Array();
var link_to_old_script_list = new Array();
var link_to_original_script_list = new Array();
var update_positions_list = new Array();
function HarvestTodo(old_node) {
function CollectDamaged(node) {
link_to_old_script_list.push(node);
for (var i = 0; i < node.children.length; i++) {
CollectDamaged(node.children[i]);
}
}
// Recursively collects all newly compiled functions that are going into
// business and should have link to the actual script updated.
function CollectNew(node_list) {
for (var i = 0; i < node_list.length; i++) {
link_to_original_script_list.push(node_list[i]);
CollectNew(node_list[i].children);
}
}
if (old_node.status == FunctionStatus.DAMAGED) {
CollectDamaged(old_node);
return;
}
if (old_node.status == FunctionStatus.UNCHANGED) {
update_positions_list.push(old_node);
} else if (old_node.status == FunctionStatus.SOURCE_CHANGED) {
update_positions_list.push(old_node);
} else if (old_node.status == FunctionStatus.CHANGED) {
replace_code_list.push(old_node);
CollectNew(old_node.unmatched_new_nodes);
}
for (var i = 0; i < old_node.children.length; i++) {
HarvestTodo(old_node.children[i]);
}
}
var preview_description = {
change_tree: DescribeChangeTree(root_old_node),
textual_diff: {
old_len: old_source.length,
new_len: new_source.length,
chunks: diff_array
},
updated: false
};
if (preview_only) {
return preview_description;
}
HarvestTodo(root_old_node);
// Collect shared infos for functions whose code need to be patched.
var replaced_function_infos = new Array();
for (var i = 0; i < replace_code_list.length; i++) {
var live_shared_function_infos =
replace_code_list[i].live_shared_function_infos;
if (live_shared_function_infos) {
for (var j = 0; j < live_shared_function_infos.length; j++) {
replaced_function_infos.push(live_shared_function_infos[j]);
}
}
}
// We haven't changed anything before this line yet.
// Committing all changes.
// Check that function being patched is not currently on stack or drop them.
var dropped_functions_number =
CheckStackActivations(replaced_function_infos, change_log);
preview_description.stack_modified = dropped_functions_number != 0;
// Our current implementation requires client to manually issue "step in"
// command for correct stack state.
preview_description[NEEDS_STEP_IN_PROPERTY_NAME] =
preview_description.stack_modified;
// Start with breakpoints. Convert their line/column positions and
// temporary remove.
var break_points_restorer = TemporaryRemoveBreakPoints(script, change_log);
var old_script;
// Create an old script only if there are function that should be linked
// to old version.
if (link_to_old_script_list.length == 0) {
%LiveEditReplaceScript(script, new_source, null);
old_script = UNDEFINED;
} else {
var old_script_name = CreateNameForOldScript(script);
// Update the script text and create a new script representing an old
// version of the script.
old_script = %LiveEditReplaceScript(script, new_source,
old_script_name);
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 = 0; i < link_to_old_script_list.length; i++) {
LinkToOldScript(link_to_old_script_list[i], old_script,
link_to_old_script_report);
}
preview_description.created_script_name = old_script_name;
}
// Link to an actual script all the functions that we are going to use.
for (var i = 0; i < link_to_original_script_list.length; i++) {
%LiveEditFunctionSetScript(
link_to_original_script_list[i].info.shared_function_info, script);
}
for (var i = 0; i < replace_code_list.length; i++) {
PatchFunctionCode(replace_code_list[i], change_log);
}
var position_patch_report = new Array();
change_log.push( {position_patched: position_patch_report} );
for (var i = 0; i < update_positions_list.length; i++) {
// TODO(LiveEdit): take into account whether it's source_changed or
// unchanged and whether positions changed at all.
PatchPositions(update_positions_list[i], diff_array,
position_patch_report);
if (update_positions_list[i].live_shared_function_infos) {
update_positions_list[i].live_shared_function_infos.
forEach(function (info) {
%LiveEditFunctionSourceUpdated(info.raw_array);
});
}
}
break_points_restorer(pos_translator, old_script);
preview_description.updated = true;
return preview_description;
}
// Function is public.
this.ApplyPatchMultiChunk = ApplyPatchMultiChunk;
// 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.
//
// All functions get compiled linked to script provided as parameter script.
// TODO(LiveEdit): consider not using actual scripts as script, because
// we have to manually erase all links right after compile.
function GatherCompileInfo(source, script) {
// 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++) {
var info = new FunctionCompileInfo(raw_compile_info[i]);
// Remove all links to the actual script. Breakpoints system and
// LiveEdit itself believe that any function in heap that points to a
// particular script is a regular function.
// For some functions we will restore this link later.
%LiveEditFunctionSetScript(info.shared_function_info, UNDEFINED);
compile_info.push(info);
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_index 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;
}
// Replaces function's Code.
function PatchFunctionCode(old_node, change_log) {
var new_info = old_node.corresponding_node.info;
if (old_node.live_shared_function_infos) {
old_node.live_shared_function_infos.forEach(function (old_info) {
%LiveEditReplaceFunctionCode(new_info.raw_array,
old_info.raw_array);
// The function got a new code. However, this new code brings all new
// instances of SharedFunctionInfo for nested functions. However,
// we want the original instances to be used wherever possible.
// (This is because old instances and new instances will be both
// linked to a script and breakpoints subsystem does not really
// expects this; neither does LiveEdit subsystem on next call).
for (var i = 0; i < old_node.children.length; i++) {
if (old_node.children[i].corresponding_node) {
var corresponding_child_info =
old_node.children[i].corresponding_node.info.
shared_function_info;
if (old_node.children[i].live_shared_function_infos) {
old_node.children[i].live_shared_function_infos.
forEach(function (old_child_info) {
%LiveEditReplaceRefToNestedFunction(
old_info.info,
corresponding_child_info,
old_child_info.info);
});
}
}
}
});
change_log.push( {function_patched: new_info.function_name} );
} else {
change_log.push( {function_patched: new_info.function_name,
function_info_not_found: true} );
}
}
// 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(old_info_node, old_script, report_array) {
if (old_info_node.live_shared_function_infos) {
old_info_node.live_shared_function_infos.
forEach(function (info) {
%LiveEditFunctionSetScript(info.info, old_script);
});
report_array.push( { name: old_info_node.info.function_name } );
} else {
report_array.push(
{ name: old_info_node.info.function_name, not_found: true } );
}
}
// Returns function that restores breakpoints.
function TemporaryRemoveBreakPoints(original_script, change_log) {
var script_break_points = GetScriptBreakPoints(original_script);
var break_points_update_report = [];
change_log.push( { break_points_update: break_points_update_report } );
var break_point_old_positions = [];
for (var i = 0; i < script_break_points.length; i++) {
var break_point = script_break_points[i];
break_point.clear();
// TODO(LiveEdit): be careful with resource offset here.
var break_point_position = Debug.findScriptSourcePosition(original_script,
break_point.line(), break_point.column());
var old_position_description = {
position: break_point_position,
line: break_point.line(),
column: break_point.column()
};
break_point_old_positions.push(old_position_description);
}
// Restores breakpoints and creates their copies in the "old" copy of
// the script.
return function (pos_translator, old_script_copy_opt) {
// Update breakpoints (change positions and restore them in old version
// of script.
for (var i = 0; i < script_break_points.length; i++) {
var break_point = script_break_points[i];
if (old_script_copy_opt) {
var clone = break_point.cloneForOtherScript(old_script_copy_opt);
clone.set(old_script_copy_opt);
break_points_update_report.push( {
type: "copied_to_old",
id: break_point.number(),
new_id: clone.number(),
positions: break_point_old_positions[i]
} );
}
var updated_position = pos_translator.Translate(
break_point_old_positions[i].position,
PosTranslator.ShiftWithTopInsideChunkHandler);
var new_location =
original_script.locationFromPosition(updated_position, false);
break_point.update_positions(new_location.line, new_location.column);
var new_position_description = {
position: updated_position,
line: new_location.line,
column: new_location.column
};
break_point.set(original_script);
break_points_update_report.push( { type: "position_changed",
id: break_point.number(),
old_positions: break_point_old_positions[i],
new_positions: new_position_description
} );
}
};
}
function Assert(condition, message) {
if (!condition) {
if (message) {
throw "Assert " + message;
} else {
throw "Assert";
}
}
}
function DiffChunk(pos1, pos2, len1, len2) {
this.pos1 = pos1;
this.pos2 = pos2;
this.len1 = len1;
this.len2 = len2;
}
function PosTranslator(diff_array) {
var chunks = new Array();
var current_diff = 0;
for (var i = 0; i < diff_array.length; i += 3) {
var pos1_begin = diff_array[i];
var pos2_begin = pos1_begin + current_diff;
var pos1_end = diff_array[i + 1];
var pos2_end = diff_array[i + 2];
chunks.push(new DiffChunk(pos1_begin, pos2_begin, pos1_end - pos1_begin,
pos2_end - pos2_begin));
current_diff = pos2_end - pos1_end;
}
this.chunks = chunks;
}
PosTranslator.prototype.GetChunks = function() {
return this.chunks;
};
PosTranslator.prototype.Translate = function(pos, inside_chunk_handler) {
var array = this.chunks;
if (array.length == 0 || pos < array[0].pos1) {
return pos;
}
var chunk_index1 = 0;
var chunk_index2 = array.length - 1;
while (chunk_index1 < chunk_index2) {
var middle_index = Math.floor((chunk_index1 + chunk_index2) / 2);
if (pos < array[middle_index + 1].pos1) {
chunk_index2 = middle_index;
} else {
chunk_index1 = middle_index + 1;
}
}
var chunk = array[chunk_index1];
if (pos >= chunk.pos1 + chunk.len1) {
return pos + chunk.pos2 + chunk.len2 - chunk.pos1 - chunk.len1;
}
if (!inside_chunk_handler) {
inside_chunk_handler = PosTranslator.DefaultInsideChunkHandler;
}
return inside_chunk_handler(pos, chunk);
};
PosTranslator.DefaultInsideChunkHandler = function(pos, diff_chunk) {
Assert(false, "Cannot translate position in changed area");
};
PosTranslator.ShiftWithTopInsideChunkHandler =
function(pos, diff_chunk) {
// We carelessly do not check whether we stay inside the chunk after
// translation.
return pos - diff_chunk.pos1 + diff_chunk.pos2;
};
var FunctionStatus = {
// No change to function or its inner functions; however its positions
// in script may have been shifted.
UNCHANGED: "unchanged",
// The code of a function remains unchanged, but something happened inside
// some inner functions.
SOURCE_CHANGED: "source changed",
// The code of a function is changed or some nested function cannot be
// properly patched so this function must be recompiled.
CHANGED: "changed",
// Function is changed but cannot be patched.
DAMAGED: "damaged"
};
function CodeInfoTreeNode(code_info, children, array_index) {
this.info = code_info;
this.children = children;
// an index in array of compile_info
this.array_index = array_index;
this.parent = UNDEFINED;
this.status = FunctionStatus.UNCHANGED;
// Status explanation is used for debugging purposes and will be shown
// in user UI if some explanations are needed.
this.status_explanation = UNDEFINED;
this.new_start_pos = UNDEFINED;
this.new_end_pos = UNDEFINED;
this.corresponding_node = UNDEFINED;
this.unmatched_new_nodes = UNDEFINED;
// 'Textual' correspondence/matching is weaker than 'pure'
// correspondence/matching. We need 'textual' level for visual presentation
// in UI, we use 'pure' level for actual code manipulation.
// Sometimes only function body is changed (functions in old and new script
// textually correspond), but we cannot patch the code, so we see them
// as an old function deleted and new function created.
this.textual_corresponding_node = UNDEFINED;
this.textually_unmatched_new_nodes = UNDEFINED;
this.live_shared_function_infos = UNDEFINED;
}
// From array of function infos that is implicitly a tree creates
// an actual tree of functions in script.
function BuildCodeInfoTree(code_info_array) {
// Throughtout all function we iterate over input array.
var index = 0;
// Recursive function that builds a branch of tree.
function BuildNode() {
var my_index = index;
index++;
var child_array = new Array();
while (index < code_info_array.length &&
code_info_array[index].outer_index == my_index) {
child_array.push(BuildNode());
}
var node = new CodeInfoTreeNode(code_info_array[my_index], child_array,
my_index);
for (var i = 0; i < child_array.length; i++) {
child_array[i].parent = node;
}
return node;
}
var root = BuildNode();
Assert(index == code_info_array.length);
return root;
}
// Applies a list of the textual diff chunks onto the tree of functions.
// Determines status of each function (from unchanged to damaged). However
// children of unchanged functions are ignored.
function MarkChangedFunctions(code_info_tree, chunks) {
// A convenient iterator over diff chunks that also translates
// positions from old to new in a current non-changed part of script.
var chunk_it = new function() {
var chunk_index = 0;
var pos_diff = 0;
this.current = function() { return chunks[chunk_index]; };
this.next = function() {
var chunk = chunks[chunk_index];
pos_diff = chunk.pos2 + chunk.len2 - (chunk.pos1 + chunk.len1);
chunk_index++;
};
this.done = function() { return chunk_index >= chunks.length; };
this.TranslatePos = function(pos) { return pos + pos_diff; };
};
// A recursive function that processes internals of a function and all its
// inner functions. Iterator chunk_it initially points to a chunk that is
// below function start.
function ProcessInternals(info_node) {
info_node.new_start_pos = chunk_it.TranslatePos(
info_node.info.start_position);
var child_index = 0;
var code_changed = false;
var source_changed = false;
// Simultaneously iterates over child functions and over chunks.
while (!chunk_it.done() &&
chunk_it.current().pos1 < info_node.info.end_position) {
if (child_index < info_node.children.length) {
var child = info_node.children[child_index];
if (child.info.end_position <= chunk_it.current().pos1) {
ProcessUnchangedChild(child);
child_index++;
continue;
} else if (child.info.start_position >=
chunk_it.current().pos1 + chunk_it.current().len1) {
code_changed = true;
chunk_it.next();
continue;
} else if (child.info.start_position <= chunk_it.current().pos1 &&
child.info.end_position >= chunk_it.current().pos1 +
chunk_it.current().len1) {
ProcessInternals(child);
source_changed = source_changed ||
( child.status != FunctionStatus.UNCHANGED );
code_changed = code_changed ||
( child.status == FunctionStatus.DAMAGED );
child_index++;
continue;
} else {
code_changed = true;
child.status = FunctionStatus.DAMAGED;
child.status_explanation =
"Text diff overlaps with function boundary";
child_index++;
continue;
}
} else {
if (chunk_it.current().pos1 + chunk_it.current().len1 <=
info_node.info.end_position) {
info_node.status = FunctionStatus.CHANGED;
chunk_it.next();
continue;
} else {
info_node.status = FunctionStatus.DAMAGED;
info_node.status_explanation =
"Text diff overlaps with function boundary";
return;
}
}
Assert("Unreachable", false);
}
while (child_index < info_node.children.length) {
var child = info_node.children[child_index];
ProcessUnchangedChild(child);
child_index++;
}
if (code_changed) {
info_node.status = FunctionStatus.CHANGED;
} else if (source_changed) {
info_node.status = FunctionStatus.SOURCE_CHANGED;
}
info_node.new_end_pos =
chunk_it.TranslatePos(info_node.info.end_position);
}
function ProcessUnchangedChild(node) {
node.new_start_pos = chunk_it.TranslatePos(node.info.start_position);
node.new_end_pos = chunk_it.TranslatePos(node.info.end_position);
}
ProcessInternals(code_info_tree);
}
// For each old function (if it is not damaged) tries to find a corresponding
// function in new script. Typically it should succeed (non-damaged functions
// by definition may only have changes inside their bodies). However there are
// reasons for correspondence not to be found; function with unmodified text
// in new script may become enclosed into other function; the innocent change
// inside function body may in fact be something like "} function B() {" that
// splits a function into 2 functions.
function FindCorrespondingFunctions(old_code_tree, new_code_tree) {
// A recursive function that tries to find a correspondence for all
// child functions and for their inner functions.
function ProcessNode(old_node, new_node) {
var scope_change_description =
IsFunctionContextLocalsChanged(old_node.info, new_node.info);
if (scope_change_description) {
old_node.status = FunctionStatus.CHANGED;
}
var old_children = old_node.children;
var new_children = new_node.children;
var unmatched_new_nodes_list = [];
var textually_unmatched_new_nodes_list = [];
var old_index = 0;
var new_index = 0;
while (old_index < old_children.length) {
if (old_children[old_index].status == FunctionStatus.DAMAGED) {
old_index++;
} else if (new_index < new_children.length) {
if (new_children[new_index].info.start_position <
old_children[old_index].new_start_pos) {
unmatched_new_nodes_list.push(new_children[new_index]);
textually_unmatched_new_nodes_list.push(new_children[new_index]);
new_index++;
} else if (new_children[new_index].info.start_position ==
old_children[old_index].new_start_pos) {
if (new_children[new_index].info.end_position ==
old_children[old_index].new_end_pos) {
old_children[old_index].corresponding_node =
new_children[new_index];
old_children[old_index].textual_corresponding_node =
new_children[new_index];
if (scope_change_description) {
old_children[old_index].status = FunctionStatus.DAMAGED;
old_children[old_index].status_explanation =
"Enclosing function is now incompatible. " +
scope_change_description;
old_children[old_index].corresponding_node = UNDEFINED;
} else if (old_children[old_index].status !=
FunctionStatus.UNCHANGED) {
ProcessNode(old_children[old_index],
new_children[new_index]);
if (old_children[old_index].status == FunctionStatus.DAMAGED) {
unmatched_new_nodes_list.push(
old_children[old_index].corresponding_node);
old_children[old_index].corresponding_node = UNDEFINED;
old_node.status = FunctionStatus.CHANGED;
}
}
} else {
old_children[old_index].status = FunctionStatus.DAMAGED;
old_children[old_index].status_explanation =
"No corresponding function in new script found";
old_node.status = FunctionStatus.CHANGED;
unmatched_new_nodes_list.push(new_children[new_index]);
textually_unmatched_new_nodes_list.push(new_children[new_index]);
}
new_index++;
old_index++;
} else {
old_children[old_index].status = FunctionStatus.DAMAGED;
old_children[old_index].status_explanation =
"No corresponding function in new script found";
old_node.status = FunctionStatus.CHANGED;
old_index++;
}
} else {
old_children[old_index].status = FunctionStatus.DAMAGED;
old_children[old_index].status_explanation =
"No corresponding function in new script found";
old_node.status = FunctionStatus.CHANGED;
old_index++;
}
}
while (new_index < new_children.length) {
unmatched_new_nodes_list.push(new_children[new_index]);
textually_unmatched_new_nodes_list.push(new_children[new_index]);
new_index++;
}
if (old_node.status == FunctionStatus.CHANGED) {
if (old_node.info.param_num != new_node.info.param_num) {
old_node.status = FunctionStatus.DAMAGED;
old_node.status_explanation = "Changed parameter number: " +
old_node.info.param_num + " and " + new_node.info.param_num;
}
}
old_node.unmatched_new_nodes = unmatched_new_nodes_list;
old_node.textually_unmatched_new_nodes =
textually_unmatched_new_nodes_list;
}
ProcessNode(old_code_tree, new_code_tree);
old_code_tree.corresponding_node = new_code_tree;
old_code_tree.textual_corresponding_node = new_code_tree;
Assert(old_code_tree.status != FunctionStatus.DAMAGED,
"Script became damaged");
}
function FindLiveSharedInfos(old_code_tree, 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]));
}
// Finds all SharedFunctionInfos that corresponds to compile info
// in old version of the script.
function FindFunctionInfos(compile_info) {
var wrappers = [];
for (var i = 0; i < shared_infos.length; i++) {
var wrapper = shared_infos[i];
if (wrapper.start_position == compile_info.start_position &&
wrapper.end_position == compile_info.end_position) {
wrappers.push(wrapper);
}
}
if (wrappers.length > 0) {
return wrappers;
}
}
function TraverseTree(node) {
node.live_shared_function_infos = FindFunctionInfos(node.info);
for (var i = 0; i < node.children.length; i++) {
TraverseTree(node.children[i]);
}
}
TraverseTree(old_code_tree);
}
// 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.code_scope_info = raw_array[5];
this.scope_info = raw_array[6];
this.outer_index = raw_array[7];
this.shared_function_info = raw_array[8];
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;
}
// Changes positions (including all statements) in function.
function PatchPositions(old_info_node, diff_array, report_array) {
if (old_info_node.live_shared_function_infos) {
old_info_node.live_shared_function_infos.forEach(function (info) {
%LiveEditPatchFunctionPositions(info.raw_array,
diff_array);
});
report_array.push( { name: old_info_node.info.function_name } );
} else {
// TODO(LiveEdit): function is not compiled yet or is already collected.
report_array.push(
{ name: old_info_node.info.function_name, info_not_found: true } );
}
}
// 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 scope heap structure, old and new version, whether it
// changed or not. Returns explanation if they differ.
function IsFunctionContextLocalsChanged(function_info1, function_info2) {
var scope_info1 = function_info1.scope_info;
var scope_info2 = function_info2.scope_info;
var scope_info1_text;
var scope_info2_text;
if (scope_info1) {
scope_info1_text = scope_info1.toString();
} else {
scope_info1_text = "";
}
if (scope_info2) {
scope_info2_text = scope_info2.toString();
} else {
scope_info2_text = "";
}
if (scope_info1_text != scope_info2_text) {
return "Variable map changed: [" + scope_info1_text +
"] => [" + scope_info2_text + "]";
}
// No differences. Return undefined.
return;
}
// 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");
}
return dropped.length;
}
// 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,
BLOCKED_UNDER_GENERATOR: 6,
BLOCKED_ACTIVE_GENERATOR: 7
};
FunctionPatchabilityStatus.SymbolName = function(code) {
var enumeration = FunctionPatchabilityStatus;
for (var name in enumeration) {
if (enumeration[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;
};
function CopyErrorPositionToDetails(e, details) {
function createPositionStruct(script, position) {
if (position == -1) return;
var location = script.locationFromPosition(position, true);
if (location == null) return;
return {
line: location.line + 1,
column: location.column + 1,
position: position
};
}
if (!("scriptObject" in e) || !("startPosition" in e)) {
return;
}
var script = e.scriptObject;
var position_struct = {
start: createPositionStruct(script, e.startPosition),
end: createPositionStruct(script, e.endPosition)
};
details.position = position_struct;
}
// A testing entry.
function GetPcFromSourcePos(func, source_pos) {
return %GetFunctionCodePositionFromSource(func, source_pos);
}
// Function is public.
this.GetPcFromSourcePos = GetPcFromSourcePos;
// LiveEdit main entry point: changes a script text to a new string.
function SetScriptSource(script, new_source, preview_only, change_log) {
var old_source = script.source;
var diff = CompareStrings(old_source, new_source);
return ApplyPatchMultiChunk(script, diff, new_source, preview_only,
change_log);
}
// Function is public.
this.SetScriptSource = SetScriptSource;
function CompareStrings(s1, s2) {
return %LiveEditCompareStrings(s1, s2);
}
// Applies the change to the script.
// The change is always a substring (change_pos, change_pos + change_len)
// being replaced with a completely different string new_str.
// This API is a legacy and is obsolete.
//
// @param {Script} script that is being changed
// @param {Array} change_log a list that collects engineer-readable
// description of what happened.
function ApplySingleChunkPatch(script, change_pos, change_len, new_str,
change_log) {
var old_source = script.source;
// Prepare new source string.
var new_source = old_source.substring(0, change_pos) +
new_str + old_source.substring(change_pos + change_len);
return ApplyPatchMultiChunk(script,
[ change_pos, change_pos + change_len, change_pos + new_str.length],
new_source, false, change_log);
}
// Creates JSON description for a change tree.
function DescribeChangeTree(old_code_tree) {
function ProcessOldNode(node) {
var child_infos = [];
for (var i = 0; i < node.children.length; i++) {
var child = node.children[i];
if (child.status != FunctionStatus.UNCHANGED) {
child_infos.push(ProcessOldNode(child));
}
}
var new_child_infos = [];
if (node.textually_unmatched_new_nodes) {
for (var i = 0; i < node.textually_unmatched_new_nodes.length; i++) {
var child = node.textually_unmatched_new_nodes[i];
new_child_infos.push(ProcessNewNode(child));
}
}
var res = {
name: node.info.function_name,
positions: DescribePositions(node),
status: node.status,
children: child_infos,
new_children: new_child_infos
};
if (node.status_explanation) {
res.status_explanation = node.status_explanation;
}
if (node.textual_corresponding_node) {
res.new_positions = DescribePositions(node.textual_corresponding_node);
}
return res;
}
function ProcessNewNode(node) {
var child_infos = [];
// Do not list ancestors.
if (false) {
for (var i = 0; i < node.children.length; i++) {
child_infos.push(ProcessNewNode(node.children[i]));
}
}
var res = {
name: node.info.function_name,
positions: DescribePositions(node),
children: child_infos,
};
return res;
}
function DescribePositions(node) {
return {
start_position: node.info.start_position,
end_position: node.info.end_position
};
}
return ProcessOldNode(old_code_tree);
}
// Restarts call frame and returns value similar to what LiveEdit returns.
function RestartFrame(frame_mirror) {
var result = frame_mirror.restart();
if (IS_STRING(result)) {
throw new Failure("Failed to restart frame: " + result);
}
var result = {};
result[NEEDS_STEP_IN_PROPERTY_NAME] = true;
return result;
}
// Function is public.
this.RestartFrame = RestartFrame;
// Functions are public for tests.
this.TestApi = {
PosTranslator: PosTranslator,
CompareStrings: CompareStrings,
ApplySingleChunkPatch: ApplySingleChunkPatch
};
};