diff --git a/api/logic/CMakeLists.txt b/api/logic/CMakeLists.txt
index 740cd886..6e9aec08 100644
--- a/api/logic/CMakeLists.txt
+++ b/api/logic/CMakeLists.txt
@@ -306,6 +306,9 @@ set(MINECRAFT_SOURCES
     # Skin upload utilities
     minecraft/SkinUpload.cpp
     minecraft/SkinUpload.h
+
+    mojang/PackageManifest.h
+    mojang/PackageManifest.cpp
     )
 
 add_unit_test(GradleSpecifier
@@ -313,6 +316,22 @@ add_unit_test(GradleSpecifier
     LIBS MultiMC_logic
     )
 
+add_executable(PackageManifest
+    mojang/PackageManifest_test.cpp
+)
+target_link_libraries(PackageManifest
+    MultiMC_logic
+    Qt5::Test
+)
+target_include_directories(PackageManifest
+    PRIVATE ../../cmake/UnitTest/
+)
+add_test(
+    NAME PackageManifest
+    COMMAND PackageManifest
+    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+)
+
 add_unit_test(MojangVersionFormat
     SOURCES minecraft/MojangVersionFormat_test.cpp
     LIBS MultiMC_logic
diff --git a/api/logic/mojang/PackageManifest.cpp b/api/logic/mojang/PackageManifest.cpp
new file mode 100644
index 00000000..42a66442
--- /dev/null
+++ b/api/logic/mojang/PackageManifest.cpp
@@ -0,0 +1,366 @@
+#include "PackageManifest.h"
+#include <Json.h>
+#include <QDir>
+#include <QDirIterator>
+#include <QCryptographicHash>
+#include <QDebug>
+
+namespace mojang_files {
+
+const Hash hash_of_empty_string = "da39a3ee5e6b4b0d3255bfef95601890afd80709";
+
+int Path::compare(const Path& rhs) const
+{
+    auto left_cursor = begin();
+    auto left_end = end();
+    auto right_cursor = rhs.begin();
+    auto right_end = rhs.end();
+
+    while (left_cursor != left_end && right_cursor != right_end)
+    {
+        if(*left_cursor < *right_cursor)
+        {
+            return -1;
+        }
+        else if(*left_cursor > *right_cursor)
+        {
+            return 1;
+        }
+        left_cursor++;
+        right_cursor++;
+    }
+
+    if(left_cursor == left_end)
+    {
+        if(right_cursor == right_end)
+        {
+            return 0;
+        }
+        return -1;
+    }
+    return 1;
+}
+
+void Package::addFile(const Path& path, const File& file) {
+    addFolder(path.parent_path());
+    files[path] = file;
+}
+
+void Package::addFolder(Path folder) {
+    if(!folder.has_parent_path()) {
+        return;
+    }
+    do {
+        folders.insert(folder);
+        folder = folder.parent_path();
+    } while(folder.has_parent_path());
+}
+
+void Package::addLink(const Path& path, const Path& target) {
+    addFolder(path.parent_path());
+    symlinks[path] = target;
+}
+
+void Package::addSource(const FileSource& source) {
+    sources[source.hash] = source;
+}
+
+
+namespace {
+void fromJson(QJsonDocument & doc, Package & out) {
+    std::set<Path> seen_paths;
+    if (!doc.isObject())
+    {
+        throw JSONValidationError("file manifest is not an object");
+    }
+    QJsonObject root = doc.object();
+
+    auto filesObj = Json::ensureObject(root, "files");
+    auto iter = filesObj.begin();
+    while (iter != filesObj.end())
+    {
+        Path objectPath = Path(iter.key());
+        auto value = iter.value();
+        iter++;
+        if(seen_paths.count(objectPath)) {
+            throw JSONValidationError("duplicate path inside manifest, the manifest is invalid");
+        }
+        if (!value.isObject())
+        {
+            throw JSONValidationError("file entry inside manifest is not an an object");
+        }
+        seen_paths.insert(objectPath);
+
+        auto fileObject = value.toObject();
+        auto type = Json::requireString(fileObject, "type");
+        if(type == "directory") {
+            out.addFolder(objectPath);
+            continue;
+        }
+        else if(type == "file") {
+            FileSource bestSource;
+            File file;
+            file.executable = Json::ensureBoolean(fileObject, "executable", false);
+            auto downloads = Json::requireObject(fileObject, "downloads");
+            for(auto iter2 = downloads.begin(); iter2 != downloads.end(); iter2++) {
+                FileSource source;
+
+                auto downloadObject = Json::requireObject(iter2.value());
+                source.hash = Json::requireString(downloadObject, "sha1");
+                source.size = Json::requireInteger(downloadObject, "size");
+                source.url = Json::requireString(downloadObject, "url");
+
+                auto compression = iter2.key();
+                if(compression == "raw") {
+                    file.hash = source.hash;
+                    file.size = source.size;
+                    source.compression = Compression::Raw;
+                }
+                else if (compression == "lzma") {
+                    source.compression = Compression::Lzma;
+                }
+                else {
+                    continue;
+                }
+                bestSource.upgrade(source);
+            }
+            if(bestSource.isBad()) {
+                throw JSONValidationError("No valid compression method for file " + iter.key());
+            }
+            out.addFile(objectPath, file);
+            out.addSource(bestSource);
+        }
+        else if(type == "link") {
+            auto target = Json::requireString(fileObject, "target");
+            out.symlinks[objectPath] = target;
+            out.addLink(objectPath, target);
+        }
+        else {
+            throw JSONValidationError("Invalid item type in manifest: " + type);
+        }
+    }
+    // make sure the containing folder exists
+    out.folders.insert(Path());
+}
+}
+
+Package Package::fromManifestContents(const QByteArray& contents)
+{
+    Package out;
+    try
+    {
+        auto doc = Json::requireDocument(contents, "Manifest");
+        fromJson(doc, out);
+        return out;
+    }
+    catch (const Exception &e)
+    {
+        qDebug() << QString("Unable to parse manifest: %1").arg(e.cause());
+        out.valid = false;
+        return out;
+    }
+}
+
+Package Package::fromManifestFile(const QString & filename) {
+    Package out;
+    try
+    {
+        auto doc = Json::requireDocument(filename, filename);
+        fromJson(doc, out);
+        return out;
+    }
+    catch (const Exception &e)
+    {
+        qDebug() << QString("Unable to parse manifest file %1: %2").arg(filename, e.cause());
+        out.valid = false;
+        return out;
+    }
+}
+
+// FIXME: Qt filesystem abstraction is bad, but ... let's hope it doesn't break too much?
+// FIXME: The error handling is just DEFICIENT
+Package Package::fromInspectedFolder(const QString& folderPath)
+{
+    QDir root(folderPath);
+
+    Package out;
+    QDirIterator iterator(folderPath, QDir::NoDotAndDotDot | QDir::AllEntries | QDir::System | QDir::Hidden, QDirIterator::Subdirectories);
+    while(iterator.hasNext()) {
+        iterator.next();
+
+        auto fileInfo = iterator.fileInfo();
+        auto relPath = root.relativeFilePath(fileInfo.filePath());
+        if(fileInfo.isSymLink()) {
+            out.addLink(relPath, fileInfo.symLinkTarget());
+        }
+        else if(fileInfo.isDir()) {
+            out.addFolder(relPath);
+        }
+        else if(fileInfo.isFile()) {
+            File f;
+            f.executable = fileInfo.isExecutable();
+            f.size = fileInfo.size();
+            // FIXME: async / optimize the hashing
+            QFile input(fileInfo.absoluteFilePath());
+            if(!input.open(QIODevice::ReadOnly)) {
+                qCritical() << "Folder inspection: Failed to open file:" << fileInfo.absoluteFilePath();
+                out.valid = false;
+                break;
+            }
+            f.hash = QCryptographicHash::hash(input.readAll(), QCryptographicHash::Sha1).toHex().constData();
+            out.addFile(relPath, f);
+        }
+        else {
+            // Something else... oh my
+            qCritical() << "Folder inspection: Unknown filesystem object:" << fileInfo.absoluteFilePath();
+            out.valid = false;
+            break;
+        }
+    }
+    out.folders.insert(Path("."));
+    out.valid = true;
+    return out;
+}
+
+namespace {
+struct shallow_first_sort
+{
+    bool operator()(const Path &lhs, const Path &rhs) const
+    {
+        auto lhs_depth = lhs.length();
+        auto rhs_depth = rhs.length();
+        if(lhs_depth < rhs_depth)
+        {
+            return true;
+        }
+        else if(lhs_depth == rhs_depth)
+        {
+            if(lhs < rhs)
+            {
+                return true;
+            }
+        }
+        return false;
+    }
+};
+
+struct deep_first_sort
+{
+    bool operator()(const Path &lhs, const Path &rhs) const
+    {
+        auto lhs_depth = lhs.length();
+        auto rhs_depth = rhs.length();
+        if(lhs_depth > rhs_depth)
+        {
+            return true;
+        }
+        else if(lhs_depth == rhs_depth)
+        {
+            if(lhs < rhs)
+            {
+                return true;
+            }
+        }
+        return false;
+    }
+};
+}
+
+UpdateOperations UpdateOperations::resolve(const Package& from, const Package& to)
+{
+    UpdateOperations out;
+
+    if(!from.valid || !to.valid) {
+        out.valid = false;
+        return out;
+    }
+
+    // Files
+    for(auto iter = from.files.begin(); iter != from.files.end(); iter++) {
+        const auto &current_hash = iter->second.hash;
+        const auto &current_executable = iter->second.executable;
+        const auto &path = iter->first;
+
+        auto iter2 = to.files.find(path);
+        if(iter2 == to.files.end()) {
+            // removed
+            out.deletes.push_back(path);
+            continue;
+        }
+        auto new_hash = iter2->second.hash;
+        auto new_executable = iter2->second.executable;
+        if (current_hash != new_hash) {
+            out.deletes.push_back(path);
+            out.downloads.emplace(
+                std::pair<Path, FileDownload>{
+                    path,
+                    FileDownload(to.sources.at(iter2->second.hash), iter2->second.executable)
+                }
+            );
+        }
+        else if (current_executable != new_executable) {
+            out.executable_fixes[path] = new_executable;
+        }
+    }
+    for(auto iter = to.files.begin(); iter != to.files.end(); iter++) {
+        auto path = iter->first;
+        if(!from.files.count(path)) {
+            out.downloads.emplace(
+                std::pair<Path, FileDownload>{
+                    path,
+                    FileDownload(to.sources.at(iter->second.hash), iter->second.executable)
+                }
+            );
+        }
+    }
+
+    // Folders
+    std::set<Path, deep_first_sort> remove_folders;
+    std::set<Path, shallow_first_sort> make_folders;
+    for(auto from_path: from.folders) {
+        auto iter = to.folders.find(from_path);
+        if(iter == to.folders.end()) {
+            remove_folders.insert(from_path);
+        }
+    }
+    for(auto & rmdir: remove_folders) {
+        out.rmdirs.push_back(rmdir);
+    }
+    for(auto to_path: to.folders) {
+        auto iter = from.folders.find(to_path);
+        if(iter == from.folders.end()) {
+            make_folders.insert(to_path);
+        }
+    }
+    for(auto & mkdir: make_folders) {
+        out.mkdirs.push_back(mkdir);
+    }
+
+    // Symlinks
+    for(auto iter = from.symlinks.begin(); iter != from.symlinks.end(); iter++) {
+        const auto &current_target = iter->second;
+        const auto &path = iter->first;
+
+        auto iter2 = to.symlinks.find(path);
+        if(iter2 == to.symlinks.end()) {
+            // removed
+            out.deletes.push_back(path);
+            continue;
+        }
+        const auto &new_target = iter2->second;
+        if (current_target != new_target) {
+            out.deletes.push_back(path);
+            out.mklinks[path] = iter2->second;
+        }
+    }
+    for(auto iter = to.symlinks.begin(); iter != to.symlinks.end(); iter++) {
+        auto path = iter->first;
+        if(!from.symlinks.count(path)) {
+            out.mklinks[path] = iter->second;
+        }
+    }
+    out.valid = true;
+    return out;
+}
+
+}
diff --git a/api/logic/mojang/PackageManifest.h b/api/logic/mojang/PackageManifest.h
new file mode 100644
index 00000000..893d4c50
--- /dev/null
+++ b/api/logic/mojang/PackageManifest.h
@@ -0,0 +1,169 @@
+#pragma once
+
+#include <QString>
+#include <map>
+#include <set>
+#include <QStringList>
+#include "tasks/Task.h"
+
+#include "multimc_logic_export.h"
+
+namespace mojang_files {
+
+using Hash = QString;
+extern const Hash empty_hash;
+
+// simple-ish path implementation. assumes always relative and does not allow '..' entries
+class MULTIMC_LOGIC_EXPORT Path
+{
+public:
+    using parts_type = QStringList;
+
+    Path() = default;
+    Path(QString string) {
+        auto parts_in = string.split('/');
+        for(auto & part: parts_in) {
+            if(part.isEmpty() || part == ".") {
+                continue;
+            }
+            if(part == "..") {
+                if(parts.size()) {
+                    parts.pop_back();
+                }
+                continue;
+            }
+            parts.push_back(part);
+        }
+    }
+
+    bool has_parent_path() const
+    {
+        return parts.size() > 0;
+    }
+
+    Path parent_path() const
+    {
+        if (parts.empty())
+            return Path();
+        return Path(parts.begin(), std::prev(parts.end()));
+    }
+
+    bool empty() const
+    {
+        return parts.empty();
+    }
+
+    int length() const
+    {
+        return parts.length();
+    }
+
+    bool operator==(const Path & rhs) const {
+        return parts == rhs.parts;
+    }
+
+    bool operator!=(const Path & rhs) const {
+        return parts != rhs.parts;
+    }
+
+    inline bool operator<(const Path& rhs) const
+    {
+        return compare(rhs) < 0;
+    }
+
+    parts_type::const_iterator begin() const
+    {
+        return parts.begin();
+    }
+
+    parts_type::const_iterator end() const
+    {
+        return parts.end();
+    }
+
+    QString toString() const {
+        return parts.join("/");
+    }
+
+private:
+    Path(const parts_type::const_iterator & start, const parts_type::const_iterator & end) {
+        parts = QStringList(start, end);
+    }
+    int compare(const Path& p) const;
+
+    parts_type parts;
+};
+
+
+enum class Compression {
+    Raw,
+    Lzma,
+    Unknown
+};
+
+
+struct MULTIMC_LOGIC_EXPORT FileSource
+{
+    Compression compression = Compression::Unknown;
+    Hash hash;
+    QString url;
+    std::size_t size = 0;
+    void upgrade(const FileSource & other) {
+        if(compression == Compression::Unknown || other.size < size) {
+            *this = other;
+        }
+    }
+    bool isBad() const {
+        return compression == Compression::Unknown;
+    }
+};
+
+struct MULTIMC_LOGIC_EXPORT File
+{
+    Hash hash;
+    bool executable;
+    std::uint64_t size = 0;
+};
+
+struct MULTIMC_LOGIC_EXPORT Package {
+    static Package fromInspectedFolder(const QString &folderPath);
+    static Package fromManifestFile(const QString &path);
+    static Package fromManifestContents(const QByteArray& contents);
+
+    explicit operator bool() const
+    {
+        return valid;
+    }
+    void addFolder(Path folder);
+    void addFile(const Path & path, const File & file);
+    void addLink(const Path & path, const Path & target);
+    void addSource(const FileSource & source);
+
+    std::map<Hash, FileSource> sources;
+    bool valid = true;
+    std::set<Path> folders;
+    std::map<Path, File> files;
+    std::map<Path, Path> symlinks;
+};
+
+struct MULTIMC_LOGIC_EXPORT FileDownload : FileSource
+{
+    FileDownload(const FileSource& source, bool executable) {
+        static_cast<FileSource &> (*this) = source;
+        this->executable = executable;
+    }
+    bool executable = false;
+};
+
+struct MULTIMC_LOGIC_EXPORT UpdateOperations {
+    static UpdateOperations resolve(const Package & from, const Package & to);
+    bool valid = false;
+    std::vector<Path> deletes;
+    std::vector<Path> rmdirs;
+    std::vector<Path> mkdirs;
+    std::map<Path, FileDownload> downloads;
+    std::map<Path, Path> mklinks;
+    std::map<Path, bool> executable_fixes;
+};
+
+}
diff --git a/api/logic/mojang/PackageManifest_test.cpp b/api/logic/mojang/PackageManifest_test.cpp
new file mode 100644
index 00000000..08628973
--- /dev/null
+++ b/api/logic/mojang/PackageManifest_test.cpp
@@ -0,0 +1,333 @@
+#include <QTest>
+#include <QDebug>
+#include "TestUtil.h"
+
+#include "mojang/PackageManifest.h"
+
+using namespace mojang_files;
+
+QDebug operator<<(QDebug debug, const Path &path)
+{
+    debug << path.toString();
+    return debug;
+}
+
+class PackageManifestTest : public QObject
+{
+    Q_OBJECT
+
+private slots:
+    void test_parse();
+    void test_parse_file();
+    void test_inspect();
+    void test_diff();
+
+    void mkdir_deep();
+    void rmdir_deep();
+
+    void identical_file();
+    void changed_file();
+    void added_file();
+    void removed_file();
+};
+
+namespace {
+QByteArray basic_manifest = R"END(
+{
+    "files": {
+        "a/b.txt": {
+            "type": "file",
+            "downloads": {
+                "raw": {
+                    "url": "http://dethware.org/b.txt",
+                    "sha1": "da39a3ee5e6b4b0d3255bfef95601890afd80709",
+                    "size": 0
+                }
+            },
+            "executable": true
+        },
+        "a/b/c": {
+            "type": "directory"
+        },
+        "a/b/c.txt": {
+            "type": "link",
+            "target": "../b.txt"
+        }
+    }
+}
+)END";
+}
+
+void PackageManifestTest::test_parse()
+{
+    auto manifest = Package::fromManifestContents(basic_manifest);
+    QCOMPARE(manifest.valid, true);
+    QCOMPARE(manifest.files.size(), 1);
+    QCOMPARE(manifest.files.count(Path("a/b.txt")), 1);
+    auto &file = manifest.files[Path("a/b.txt")];
+    QCOMPARE(file.executable, true);
+    QCOMPARE(file.hash, "da39a3ee5e6b4b0d3255bfef95601890afd80709");
+    QCOMPARE(file.size, 0);
+    QCOMPARE(manifest.folders.size(), 4);
+    QCOMPARE(manifest.folders.count(Path(".")), 1);
+    QCOMPARE(manifest.folders.count(Path("a")), 1);
+    QCOMPARE(manifest.folders.count(Path("a/b")), 1);
+    QCOMPARE(manifest.folders.count(Path("a/b/c")), 1);
+    QCOMPARE(manifest.symlinks.size(), 1);
+    auto symlinkPath = Path("a/b/c.txt");
+    QCOMPARE(manifest.symlinks.count(symlinkPath), 1);
+    auto &symlink = manifest.symlinks[symlinkPath];
+    QCOMPARE(symlink, Path("../b.txt"));
+    QCOMPARE(manifest.sources.size(), 1);
+}
+
+void PackageManifestTest::test_parse_file() {
+    auto path = QFINDTESTDATA("testdata/1.8.0_202-x64.json");
+    auto manifest = Package::fromManifestFile(path);
+    QCOMPARE(manifest.valid, true);
+}
+
+void PackageManifestTest::test_inspect() {
+    auto path = QFINDTESTDATA("testdata/inspect/");
+    auto manifest = Package::fromInspectedFolder(path);
+    QCOMPARE(manifest.valid, true);
+    QCOMPARE(manifest.files.size(), 1);
+    QCOMPARE(manifest.files.count(Path("a/b.txt")), 1);
+    auto &file = manifest.files[Path("a/b.txt")];
+    QCOMPARE(file.executable, true);
+    QCOMPARE(file.hash, "da39a3ee5e6b4b0d3255bfef95601890afd80709");
+    QCOMPARE(file.size, 0);
+    QCOMPARE(manifest.folders.size(), 3);
+    QCOMPARE(manifest.folders.count(Path(".")), 1);
+    QCOMPARE(manifest.folders.count(Path("a")), 1);
+    QCOMPARE(manifest.folders.count(Path("a/b")), 1);
+    QCOMPARE(manifest.symlinks.size(), 1);
+}
+
+void PackageManifestTest::test_diff() {
+    auto path = QFINDTESTDATA("testdata/inspect/");
+    auto from = Package::fromInspectedFolder(path);
+    auto to = Package::fromManifestContents(basic_manifest);
+    auto operations = UpdateOperations::resolve(from, to);
+    QCOMPARE(operations.valid, true);
+    QCOMPARE(operations.mkdirs.size(), 1);
+    QCOMPARE(operations.mkdirs[0], Path("a/b/c"));
+
+    QCOMPARE(operations.rmdirs.size(), 0);
+    QCOMPARE(operations.deletes.size(), 1);
+    QCOMPARE(operations.deletes[0], Path("a/b/b.txt"));
+    QCOMPARE(operations.downloads.size(), 0);
+    QCOMPARE(operations.mklinks.size(), 1);
+    QCOMPARE(operations.mklinks.count(Path("a/b/c.txt")), 1);
+    QCOMPARE(operations.mklinks[Path("a/b/c.txt")], Path("../b.txt"));
+}
+
+void PackageManifestTest::mkdir_deep() {
+
+    Package from;
+    auto to = Package::fromManifestContents(R"END(
+{
+    "files": {
+        "a/b/c/d/e": {
+            "type": "directory"
+        }
+    }
+}
+)END");
+    auto operations = UpdateOperations::resolve(from, to);
+    QCOMPARE(operations.deletes.size(), 0);
+    QCOMPARE(operations.rmdirs.size(), 0);
+
+    QCOMPARE(operations.mkdirs.size(), 6);
+    QCOMPARE(operations.mkdirs[0], Path("."));
+    QCOMPARE(operations.mkdirs[1], Path("a"));
+    QCOMPARE(operations.mkdirs[2], Path("a/b"));
+    QCOMPARE(operations.mkdirs[3], Path("a/b/c"));
+    QCOMPARE(operations.mkdirs[4], Path("a/b/c/d"));
+    QCOMPARE(operations.mkdirs[5], Path("a/b/c/d/e"));
+
+    QCOMPARE(operations.downloads.size(), 0);
+    QCOMPARE(operations.mklinks.size(), 0);
+    QCOMPARE(operations.executable_fixes.size(), 0);
+}
+
+void PackageManifestTest::rmdir_deep() {
+
+    Package to;
+    auto from = Package::fromManifestContents(R"END(
+{
+    "files": {
+        "a/b/c/d/e": {
+            "type": "directory"
+        }
+    }
+}
+)END");
+    auto operations = UpdateOperations::resolve(from, to);
+    QCOMPARE(operations.deletes.size(), 0);
+
+    QCOMPARE(operations.rmdirs.size(), 6);
+    QCOMPARE(operations.rmdirs[0], Path("a/b/c/d/e"));
+    QCOMPARE(operations.rmdirs[1], Path("a/b/c/d"));
+    QCOMPARE(operations.rmdirs[2], Path("a/b/c"));
+    QCOMPARE(operations.rmdirs[3], Path("a/b"));
+    QCOMPARE(operations.rmdirs[4], Path("a"));
+    QCOMPARE(operations.rmdirs[5], Path("."));
+
+    QCOMPARE(operations.mkdirs.size(), 0);
+    QCOMPARE(operations.downloads.size(), 0);
+    QCOMPARE(operations.mklinks.size(), 0);
+    QCOMPARE(operations.executable_fixes.size(), 0);
+}
+
+void PackageManifestTest::identical_file() {
+    QByteArray manifest = R"END(
+{
+    "files": {
+        "a/b/c/d/empty.txt": {
+            "type": "file",
+            "downloads": {
+                "raw": {
+                    "url": "http://dethware.org/empty.txt",
+                    "sha1": "da39a3ee5e6b4b0d3255bfef95601890afd80709",
+                    "size": 0
+                }
+            },
+            "executable": false
+        }
+    }
+}
+)END";
+    auto from = Package::fromManifestContents(manifest);
+    auto to = Package::fromManifestContents(manifest);
+    auto operations = UpdateOperations::resolve(from, to);
+    QCOMPARE(operations.deletes.size(), 0);
+    QCOMPARE(operations.rmdirs.size(), 0);
+    QCOMPARE(operations.mkdirs.size(), 0);
+    QCOMPARE(operations.downloads.size(), 0);
+    QCOMPARE(operations.mklinks.size(), 0);
+    QCOMPARE(operations.executable_fixes.size(), 0);
+}
+
+void PackageManifestTest::changed_file() {
+    auto from = Package::fromManifestContents(R"END(
+{
+    "files": {
+        "a/b/c/d/file": {
+            "type": "file",
+            "downloads": {
+                "raw": {
+                    "url": "http://dethware.org/empty.txt",
+                    "sha1": "da39a3ee5e6b4b0d3255bfef95601890afd80709",
+                    "size": 0
+                }
+            },
+            "executable": false
+        }
+    }
+}
+)END");
+    auto to = Package::fromManifestContents(R"END(
+{
+    "files": {
+        "a/b/c/d/file": {
+            "type": "file",
+            "downloads": {
+                "raw": {
+                    "url": "http://dethware.org/space.txt",
+                    "sha1": "dd122581c8cd44d0227f9c305581ffcb4b6f1b46",
+                    "size": 1
+                }
+            },
+            "executable": false
+        }
+    }
+}
+)END");
+    auto operations = UpdateOperations::resolve(from, to);
+    QCOMPARE(operations.deletes.size(), 1);
+    QCOMPARE(operations.deletes[0], Path("a/b/c/d/file"));
+    QCOMPARE(operations.rmdirs.size(), 0);
+    QCOMPARE(operations.mkdirs.size(), 0);
+    QCOMPARE(operations.downloads.size(), 1);
+    QCOMPARE(operations.mklinks.size(), 0);
+    QCOMPARE(operations.executable_fixes.size(), 0);
+}
+
+void PackageManifestTest::added_file() {
+    auto from = Package::fromManifestContents(R"END(
+{
+    "files": {
+        "a/b/c/d": {
+            "type": "directory"
+        }
+    }
+}
+)END");
+    auto to = Package::fromManifestContents(R"END(
+{
+    "files": {
+        "a/b/c/d/file": {
+            "type": "file",
+            "downloads": {
+                "raw": {
+                    "url": "http://dethware.org/space.txt",
+                    "sha1": "dd122581c8cd44d0227f9c305581ffcb4b6f1b46",
+                    "size": 1
+                }
+            },
+            "executable": false
+        }
+    }
+}
+)END");
+    auto operations = UpdateOperations::resolve(from, to);
+    QCOMPARE(operations.deletes.size(), 0);
+    QCOMPARE(operations.rmdirs.size(), 0);
+    QCOMPARE(operations.mkdirs.size(), 0);
+    QCOMPARE(operations.downloads.size(), 1);
+    QCOMPARE(operations.mklinks.size(), 0);
+    QCOMPARE(operations.executable_fixes.size(), 0);
+}
+
+void PackageManifestTest::removed_file() {
+    auto from = Package::fromManifestContents(R"END(
+{
+    "files": {
+        "a/b/c/d/file": {
+            "type": "file",
+            "downloads": {
+                "raw": {
+                    "url": "http://dethware.org/space.txt",
+                    "sha1": "dd122581c8cd44d0227f9c305581ffcb4b6f1b46",
+                    "size": 1
+                }
+            },
+            "executable": false
+        }
+    }
+}
+)END");
+    auto to = Package::fromManifestContents(R"END(
+{
+    "files": {
+        "a/b/c/d": {
+            "type": "directory"
+        }
+    }
+}
+)END");
+    auto operations = UpdateOperations::resolve(from, to);
+    QCOMPARE(operations.deletes.size(), 1);
+    QCOMPARE(operations.deletes[0], Path("a/b/c/d/file"));
+    QCOMPARE(operations.rmdirs.size(), 0);
+    QCOMPARE(operations.mkdirs.size(), 0);
+    QCOMPARE(operations.downloads.size(), 0);
+    QCOMPARE(operations.mklinks.size(), 0);
+    QCOMPARE(operations.executable_fixes.size(), 0);
+}
+
+QTEST_GUILESS_MAIN(PackageManifestTest)
+
+#include "PackageManifest_test.moc"
+
diff --git a/api/logic/mojang/testdata/1.8.0_202-x64.json b/api/logic/mojang/testdata/1.8.0_202-x64.json
new file mode 100644
index 00000000..3d99d719
Binary files /dev/null and b/api/logic/mojang/testdata/1.8.0_202-x64.json differ
diff --git a/api/logic/mojang/testdata/inspect/a/b.txt b/api/logic/mojang/testdata/inspect/a/b.txt
new file mode 100755
index 00000000..e69de29b
diff --git a/api/logic/mojang/testdata/inspect/a/b/b.txt b/api/logic/mojang/testdata/inspect/a/b/b.txt
new file mode 120000
index 00000000..4e19a044
--- /dev/null
+++ b/api/logic/mojang/testdata/inspect/a/b/b.txt
@@ -0,0 +1 @@
+../b.txt
\ No newline at end of file