Use source map (if present) to translate source file references in backtrace.

react_juce/core/EcmascriptEngine.cpp

@@ -96,4 +96,140 @@ namespace reactjuce
         mPimpl->debuggerDetach();
     }
 
+    //==============================================================================
+    SourceMap::SourceMap(const juce::String& source, const juce::String& map)
+        : mapLoaded(false)
+        , sourcePath(source)
+    {
+        mapLoaded = LoadMap(map);
+    }
+
+    SourceMap::SourceMap(const juce::String& source, const juce::File& map)
+        : mapLoaded(false)
+        , sourcePath(source)
+    {
+        if (map.existsAsFile())
+            mapLoaded = LoadMap(map.loadFileAsString());
+    }
+
+    SourceMap::Location SourceMap::translate(int line, int col) const
+    {
+        // line and col are 1-based.
+        SourceMap::Location failRes{sourcePath, line, col};
+        if (!mapLoaded || line <= 0 || col <= 0 || static_cast<std::size_t>(line) > mappings.size())
+            return failRes;
+
+        const Segment* use_segment = nullptr;
+        for (const auto& segment : mappings[line - 1])
+            if (segment.segStartCol >= col)
+                break;
+            else
+                use_segment = &segment;
+
+        if (!use_segment || !use_segment->gotSourceMap || use_segment->origSourceId < 0 ||
+            static_cast<std::size_t>(use_segment->origSourceId) >= sources.size())
+            return failRes;
+
+        return
+            {
+                sources[use_segment->origSourceId],
+                use_segment->origStartLine + 1,
+                col - use_segment->segStartCol + use_segment->origStartCol
+            };
+    }
+
+    bool SourceMap::LoadMap(const juce::String& map)
+    {
+        auto json = juce::JSON::parse(map);
+        const auto fileVersion = json.getProperty("version", juce::var());
+        const auto fileMappings = json.getProperty("mappings", juce::var());
+        auto fileSources = json.getProperty("sources", juce::var());
+
+        if (!fileVersion.isInt() || static_cast<int>(fileVersion) != 3 ||
+            !fileMappings.isString() || !fileSources.isArray() )
+            return false;
+
+        for (auto &i : *fileSources.getArray())
+        {
+            if (!i.isString())
+                return false;
+            sources.emplace_back(std::move(i.toString()));
+        }
+
+        bool firstSegmentInLine = true;
+        std::vector<Segment> lineSegments;
+        Segment segment;
+        Segment lastSegment;
+        int segmentIntNo = 0;
+        int segmentIntVal = 0;
+        int segmentIntCharNo = 0;
+
+        for (auto p = fileMappings.toString().toRawUTF8(); *p; ++p)
+        {
+            if (*p == ',' || *p == ';')
+            {
+                segmentIntNo = segmentIntVal = segmentIntCharNo = 0;
+                if (firstSegmentInLine)
+                    firstSegmentInLine = false;
+                else
+                    segment.segStartCol += lastSegment.segStartCol;
+                segment.origSourceId += lastSegment.origSourceId;
+                segment.origStartLine += lastSegment.origStartLine;
+                segment.origStartCol += lastSegment.origStartCol;
+                lineSegments.push_back(segment);
+                lastSegment = segment;
+                segment = Segment();
+
+                if (*p == ';')
+                {
+                    mappings.emplace_back(std::move(lineSegments));
+                    firstSegmentInLine = true;
+                }
+            }
+            else
+            {
+                static const std::string base64_charset =
+                    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                    "abcdefghijklmnopqrstuvwxyz"
+                    "0123456789+/";
+                auto i = base64_charset.find(*p);
+                if (i == std::string::npos)
+                    return false;
+                segmentIntVal |= ((i & 0x1f) << (segmentIntCharNo * 5));
+                if (i & 0x20)
+                    ++segmentIntCharNo;
+                else
+                {
+                    bool neg = (segmentIntVal & 1);
+                    segmentIntVal >>= 1;
+                    if (neg)
+                        segmentIntVal = -segmentIntVal;
+                    switch(segmentIntNo++)
+                    {
+                    case 0:
+                        segment.segStartCol = segmentIntVal;
+                        break;
+
+                    case 1:
+                        segment.origSourceId = segmentIntVal;
+                        segment.gotSourceMap = true;
+                        break;
+
+                    case 2:
+                        segment.origStartLine = segmentIntVal;
+                        break;
+
+                    case 3:
+                        segment.origStartCol = segmentIntVal;
+                        break;
+                    }
+                    segmentIntVal = segmentIntCharNo = 0;
+                }
+            }
+        }
+        // In case there's no final terminator.
+        mappings.emplace_back(std::move(lineSegments));
+
+        return true;
+    }
 }

react_juce/core/EcmascriptEngine.h

@@ -10,7 +10,7 @@
 #pragma once
 
 #include <unordered_map>
-
+#include <vector>
 
 namespace reactjuce
 {
@@ -178,4 +178,41 @@ namespace reactjuce
         return invoke(name, vargs);
     }
 
+    //==============================================================================
+    /** Utility helper class for Ecmascript implementations. Read a SourceMap and
+     *  provide translations to original source location.
+     */
+    class SourceMap
+    {
+    public:
+        struct Location
+        {
+            const juce::String& file;
+            int line;
+            int col;
+        };
+
+        SourceMap(const juce::String& source, const juce::String& map);
+        SourceMap(const juce::String& source, const juce::File& map);
+        ~SourceMap() = default;
+
+        Location translate(int line, int col) const;
+
+    private:
+        struct Segment
+        {
+            int segStartCol = 0;
+            int origSourceId = 0;
+            int origStartLine = 0;
+            int origStartCol = 0;
+            bool gotSourceMap = false;
+        };
+
+        bool LoadMap(const juce::String& map);
+
+        bool mapLoaded;
+        juce::String sourcePath;
+        std::vector<juce::String> sources;
+        std::vector<std::vector<Segment>> mappings;
+    };
 }

react_juce/core/EcmascriptEngine_Hermes.cpp

@@ -1,3 +1,5 @@
+#include <regex>
+
 #include "EcmascriptEngine.h"
 
 #if _MSC_VER
@@ -247,6 +249,34 @@ namespace reactjuce
             return {};
         }
 
+        //==============================================================================
+        juce::String sourceMapError(const juce::String &err)
+        {
+            std::unordered_map<juce::String, std::unique_ptr<SourceMap>> maps;
+            std::string s = err.toStdString();
+            juce::String res;
+            const std::regex fileRef("\\((.*):([0-9]+):([0-9]+)\\)", std::regex_constants::ECMAScript);
+            std::smatch m;
+
+            while (std::regex_search(s, m, fileRef))
+            {
+                const juce::String source = m[1].str();
+                const int line = std::stoi(m[2].str());
+                const int col = std::stoi(m[3].str());
+
+                if (maps.find(source) == maps.end())
+                    maps.insert({source, std::make_unique<SourceMap>(source, juce::File(source + ".map"))});
+                const auto newloc = maps[source]->translate(line, col);
+                juce::String file = newloc.file;
+                if (file.startsWith("webpack:///"))
+                    file = newloc.file.replaceFirstOccurrenceOf("webpack:///", "");
+
+                res += juce::String(m.prefix().str()) + "(" + file + ":" + juce::String(newloc.line) + ":" + juce::String(newloc.col) + ")";
+                s = m.suffix();
+            }
+            return res + s;
+        }
+
         //==============================================================================
     }
 
@@ -350,7 +380,7 @@ namespace reactjuce
             }
             catch (const jsi::JSIException &e)
             {
-                throw Error(e.what());
+                throw Error(sourceMapError(e.what()));
             }
         }
 
@@ -366,7 +396,7 @@ namespace reactjuce
             }
             catch (const jsi::JSIException &e)
             {
-                throw Error(e.what());
+                throw Error(sourceMapError(e.what()));
             }
         }
 
@@ -385,7 +415,7 @@ namespace reactjuce
             }
             catch (const jsi::JSIException &e)
             {
-                throw Error(e.what());
+                throw Error(sourceMapError(e.what()));
             }
         }
 
@@ -451,7 +481,7 @@ namespace reactjuce
             }
             catch(const jsi::JSIException &e)
             {
-                throw Error(e.what());
+                throw Error(sourceMapError(e.what()));
             }
         }