tools/aapt2/ResourceUtils.cpp

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "ResourceUtils.h"
#include "util/Util.h"

#include <androidfw/ResourceTypes.h>
#include <sstream>

namespace aapt {
namespace ResourceUtils {

bool extractResourceName(const StringPiece16& str, StringPiece16* outPackage,
                         StringPiece16* outType, StringPiece16* outEntry) {
    bool hasPackageSeparator = false;
    bool hasTypeSeparator = false;
    const char16_t* start = str.data();
    const char16_t* end = start + str.size();
    const char16_t* current = start;
    while (current != end) {
        if (outType->size() == 0 && *current == u'/') {
            hasTypeSeparator = true;
            outType->assign(start, current - start);
            start = current + 1;
        } else if (outPackage->size() == 0 && *current == u':') {
            hasPackageSeparator = true;
            outPackage->assign(start, current - start);
            start = current + 1;
        }
        current++;
    }
    outEntry->assign(start, end - start);

    return !(hasPackageSeparator && outPackage->empty()) && !(hasTypeSeparator && outType->empty());
}

bool tryParseReference(const StringPiece16& str, ResourceNameRef* outRef, bool* outCreate,
                       bool* outPrivate) {
    StringPiece16 trimmedStr(util::trimWhitespace(str));
    if (trimmedStr.empty()) {
        return false;
    }

    bool create = false;
    bool priv = false;
    if (trimmedStr.data()[0] == u'@') {
        size_t offset = 1;
        if (trimmedStr.data()[1] == u'+') {
            create = true;
            offset += 1;
        } else if (trimmedStr.data()[1] == u'*') {
            priv = true;
            offset += 1;
        }
        StringPiece16 package;
        StringPiece16 type;
        StringPiece16 entry;
        if (!extractResourceName(trimmedStr.substr(offset, trimmedStr.size() - offset),
                                 &package, &type, &entry)) {
            return false;
        }

        const ResourceType* parsedType = parseResourceType(type);
        if (!parsedType) {
            return false;
        }

        if (entry.empty()) {
            return false;
        }

        if (create && *parsedType != ResourceType::kId) {
            return false;
        }

        if (outRef) {
            outRef->package = package;
            outRef->type = *parsedType;
            outRef->entry = entry;
        }

        if (outCreate) {
            *outCreate = create;
        }

        if (outPrivate) {
            *outPrivate = priv;
        }
        return true;
    }
    return false;
}

bool isReference(const StringPiece16& str) {
    return tryParseReference(str, nullptr, nullptr, nullptr);
}

bool tryParseAttributeReference(const StringPiece16& str, ResourceNameRef* outRef) {
    StringPiece16 trimmedStr(util::trimWhitespace(str));
    if (trimmedStr.empty()) {
        return false;
    }

    if (*trimmedStr.data() == u'?') {
        StringPiece16 package;
        StringPiece16 type;
        StringPiece16 entry;
        if (!extractResourceName(trimmedStr.substr(1, trimmedStr.size() - 1),
                                 &package, &type, &entry)) {
            return false;
        }

        if (!type.empty() && type != u"attr") {
            return false;
        }

        if (entry.empty()) {
            return false;
        }

        if (outRef) {
            outRef->package = package;
            outRef->type = ResourceType::kAttr;
            outRef->entry = entry;
        }
        return true;
    }
    return false;
}

bool isAttributeReference(const StringPiece16& str) {
    return tryParseAttributeReference(str, nullptr);
}

/*
 * Style parent's are a bit different. We accept the following formats:
 *
 * @[package:]style/<entry>
 * ?[package:]style/<entry>
 * <package>:[style/]<entry>
 * [package:style/]<entry>
 */
Maybe<Reference> parseStyleParentReference(const StringPiece16& str, std::string* outError) {
    if (str.empty()) {
        return {};
    }

    StringPiece16 name = str;

    bool hasLeadingIdentifiers = false;
    bool privateRef = false;

    // Skip over these identifiers. A style's parent is a normal reference.
    if (name.data()[0] == u'@' || name.data()[0] == u'?') {
        hasLeadingIdentifiers = true;
        name = name.substr(1, name.size() - 1);
        if (name.data()[0] == u'*') {
            privateRef = true;
            name = name.substr(1, name.size() - 1);
        }
    }

    ResourceNameRef ref;
    ref.type = ResourceType::kStyle;

    StringPiece16 typeStr;
    extractResourceName(name, &ref.package, &typeStr, &ref.entry);
    if (!typeStr.empty()) {
        // If we have a type, make sure it is a Style.
        const ResourceType* parsedType = parseResourceType(typeStr);
        if (!parsedType || *parsedType != ResourceType::kStyle) {
            std::stringstream err;
            err << "invalid resource type '" << typeStr << "' for parent of style";
            *outError = err.str();
            return {};
        }
    } else {
        // No type was defined, this should not have a leading identifier.
        if (hasLeadingIdentifiers) {
            std::stringstream err;
            err << "invalid parent reference '" << str << "'";
            *outError = err.str();
            return {};
        }
    }

    if (!hasLeadingIdentifiers && ref.package.empty() && !typeStr.empty()) {
        std::stringstream err;
        err << "invalid parent reference '" << str << "'";
        *outError = err.str();
        return {};
    }

    Reference result(ref);
    result.privateReference = privateRef;
    return result;
}

std::unique_ptr<Reference> tryParseReference(const StringPiece16& str, bool* outCreate) {
    ResourceNameRef ref;
    bool privateRef = false;
    if (tryParseReference(str, &ref, outCreate, &privateRef)) {
        std::unique_ptr<Reference> value = util::make_unique<Reference>(ref);
        value->privateReference = privateRef;
        return value;
    }

    if (tryParseAttributeReference(str, &ref)) {
        if (outCreate) {
            *outCreate = false;
        }
        return util::make_unique<Reference>(ref, Reference::Type::kAttribute);
    }
    return {};
}

std::unique_ptr<BinaryPrimitive> tryParseNullOrEmpty(const StringPiece16& str) {
    StringPiece16 trimmedStr(util::trimWhitespace(str));
    android::Res_value value = { };
    if (trimmedStr == u"@null") {
        // TYPE_NULL with data set to 0 is interpreted by the runtime as an error.
        // Instead we set the data type to TYPE_REFERENCE with a value of 0.
        value.dataType = android::Res_value::TYPE_REFERENCE;
    } else if (trimmedStr == u"@empty") {
        // TYPE_NULL with value of DATA_NULL_EMPTY is handled fine by the runtime.
        value.dataType = android::Res_value::TYPE_NULL;
        value.data = android::Res_value::DATA_NULL_EMPTY;
    } else {
        return {};
    }
    return util::make_unique<BinaryPrimitive>(value);
}

std::unique_ptr<BinaryPrimitive> tryParseEnumSymbol(const Attribute* enumAttr,
                                                    const StringPiece16& str) {
    StringPiece16 trimmedStr(util::trimWhitespace(str));
    for (const Attribute::Symbol& symbol : enumAttr->symbols) {
        // Enum symbols are stored as @package:id/symbol resources,
        // so we need to match against the 'entry' part of the identifier.
        const ResourceName& enumSymbolResourceName = symbol.symbol.name.value();
        if (trimmedStr == enumSymbolResourceName.entry) {
            android::Res_value value = { };
            value.dataType = android::Res_value::TYPE_INT_DEC;
            value.data = symbol.value;
            return util::make_unique<BinaryPrimitive>(value);
        }
    }
    return {};
}

std::unique_ptr<BinaryPrimitive> tryParseFlagSymbol(const Attribute* flagAttr,
                                                    const StringPiece16& str) {
    android::Res_value flags = { };
    flags.dataType = android::Res_value::TYPE_INT_DEC;

    for (StringPiece16 part : util::tokenize(str, u'|')) {
        StringPiece16 trimmedPart = util::trimWhitespace(part);

        bool flagSet = false;
        for (const Attribute::Symbol& symbol : flagAttr->symbols) {
            // Flag symbols are stored as @package:id/symbol resources,
            // so we need to match against the 'entry' part of the identifier.
            const ResourceName& flagSymbolResourceName = symbol.symbol.name.value();
            if (trimmedPart == flagSymbolResourceName.entry) {
                flags.data |= symbol.value;
                flagSet = true;
                break;
            }
        }

        if (!flagSet) {
            return {};
        }
    }
    return util::make_unique<BinaryPrimitive>(flags);
}

static uint32_t parseHex(char16_t c, bool* outError) {
    if (c >= u'0' && c <= u'9') {
        return c - u'0';
    } else if (c >= u'a' && c <= u'f') {
        return c - u'a' + 0xa;
    } else if (c >= u'A' && c <= u'F') {
        return c - u'A' + 0xa;
    } else {
        *outError = true;
        return 0xffffffffu;
    }
}

std::unique_ptr<BinaryPrimitive> tryParseColor(const StringPiece16& str) {
    StringPiece16 colorStr(util::trimWhitespace(str));
    const char16_t* start = colorStr.data();
    const size_t len = colorStr.size();
    if (len == 0 || start[0] != u'#') {
        return {};
    }

    android::Res_value value = { };
    bool error = false;
    if (len == 4) {
        value.dataType = android::Res_value::TYPE_INT_COLOR_RGB4;
        value.data = 0xff000000u;
        value.data |= parseHex(start[1], &error) << 20;
        value.data |= parseHex(start[1], &error) << 16;
        value.data |= parseHex(start[2], &error) << 12;
        value.data |= parseHex(start[2], &error) << 8;
        value.data |= parseHex(start[3], &error) << 4;
        value.data |= parseHex(start[3], &error);
    } else if (len == 5) {
        value.dataType = android::Res_value::TYPE_INT_COLOR_ARGB4;
        value.data |= parseHex(start[1], &error) << 28;
        value.data |= parseHex(start[1], &error) << 24;
        value.data |= parseHex(start[2], &error) << 20;
        value.data |= parseHex(start[2], &error) << 16;
        value.data |= parseHex(start[3], &error) << 12;
        value.data |= parseHex(start[3], &error) << 8;
        value.data |= parseHex(start[4], &error) << 4;
        value.data |= parseHex(start[4], &error);
    } else if (len == 7) {
        value.dataType = android::Res_value::TYPE_INT_COLOR_RGB8;
        value.data = 0xff000000u;
        value.data |= parseHex(start[1], &error) << 20;
        value.data |= parseHex(start[2], &error) << 16;
        value.data |= parseHex(start[3], &error) << 12;
        value.data |= parseHex(start[4], &error) << 8;
        value.data |= parseHex(start[5], &error) << 4;
        value.data |= parseHex(start[6], &error);
    } else if (len == 9) {
        value.dataType = android::Res_value::TYPE_INT_COLOR_ARGB8;
        value.data |= parseHex(start[1], &error) << 28;
        value.data |= parseHex(start[2], &error) << 24;
        value.data |= parseHex(start[3], &error) << 20;
        value.data |= parseHex(start[4], &error) << 16;
        value.data |= parseHex(start[5], &error) << 12;
        value.data |= parseHex(start[6], &error) << 8;
        value.data |= parseHex(start[7], &error) << 4;
        value.data |= parseHex(start[8], &error);
    } else {
        return {};
    }
    return error ? std::unique_ptr<BinaryPrimitive>() : util::make_unique<BinaryPrimitive>(value);
}

bool tryParseBool(const StringPiece16& str, bool* outValue) {
    StringPiece16 trimmedStr(util::trimWhitespace(str));
    if (trimmedStr == u"true" || trimmedStr == u"TRUE") {
        if (outValue) {
            *outValue = true;
        }
        return true;
    } else if (trimmedStr == u"false" || trimmedStr == u"FALSE") {
        if (outValue) {
            *outValue = false;
        }
        return true;
    }
    return false;
}

std::unique_ptr<BinaryPrimitive> tryParseBool(const StringPiece16& str) {
    bool result = false;
    if (tryParseBool(str, &result)) {
        android::Res_value value = {};
        value.dataType = android::Res_value::TYPE_INT_BOOLEAN;

        if (result) {
            value.data = 0xffffffffu;
        } else {
            value.data = 0;
        }
        return util::make_unique<BinaryPrimitive>(value);
    }
    return {};
}

std::unique_ptr<BinaryPrimitive> tryParseInt(const StringPiece16& str) {
    android::Res_value value;
    if (!android::ResTable::stringToInt(str.data(), str.size(), &value)) {
        return {};
    }
    return util::make_unique<BinaryPrimitive>(value);
}

std::unique_ptr<BinaryPrimitive> tryParseFloat(const StringPiece16& str) {
    android::Res_value value;
    if (!android::ResTable::stringToFloat(str.data(), str.size(), &value)) {
        return {};
    }
    return util::make_unique<BinaryPrimitive>(value);
}

uint32_t androidTypeToAttributeTypeMask(uint16_t type) {
    switch (type) {
    case android::Res_value::TYPE_NULL:
    case android::Res_value::TYPE_REFERENCE:
    case android::Res_value::TYPE_ATTRIBUTE:
    case android::Res_value::TYPE_DYNAMIC_REFERENCE:
        return android::ResTable_map::TYPE_REFERENCE;

    case android::Res_value::TYPE_STRING:
        return android::ResTable_map::TYPE_STRING;

    case android::Res_value::TYPE_FLOAT:
        return android::ResTable_map::TYPE_FLOAT;

    case android::Res_value::TYPE_DIMENSION:
        return android::ResTable_map::TYPE_DIMENSION;

    case android::Res_value::TYPE_FRACTION:
        return android::ResTable_map::TYPE_FRACTION;

    case android::Res_value::TYPE_INT_DEC:
    case android::Res_value::TYPE_INT_HEX:
        return android::ResTable_map::TYPE_INTEGER | android::ResTable_map::TYPE_ENUM
                | android::ResTable_map::TYPE_FLAGS;

    case android::Res_value::TYPE_INT_BOOLEAN:
        return android::ResTable_map::TYPE_BOOLEAN;

    case android::Res_value::TYPE_INT_COLOR_ARGB8:
    case android::Res_value::TYPE_INT_COLOR_RGB8:
    case android::Res_value::TYPE_INT_COLOR_ARGB4:
    case android::Res_value::TYPE_INT_COLOR_RGB4:
        return android::ResTable_map::TYPE_COLOR;

    default:
        return 0;
    };
}

std::unique_ptr<Item> parseItemForAttribute(
        const StringPiece16& value, uint32_t typeMask,
        std::function<void(const ResourceName&)> onCreateReference) {
    std::unique_ptr<BinaryPrimitive> nullOrEmpty = tryParseNullOrEmpty(value);
    if (nullOrEmpty) {
        return std::move(nullOrEmpty);
    }

    bool create = false;
    std::unique_ptr<Reference> reference = tryParseReference(value, &create);
    if (reference) {
        if (create && onCreateReference) {
            onCreateReference(reference->name.value());
        }
        return std::move(reference);
    }

    if (typeMask & android::ResTable_map::TYPE_COLOR) {
        // Try parsing this as a color.
        std::unique_ptr<BinaryPrimitive> color = tryParseColor(value);
        if (color) {
            return std::move(color);
        }
    }

    if (typeMask & android::ResTable_map::TYPE_BOOLEAN) {
        // Try parsing this as a boolean.
        std::unique_ptr<BinaryPrimitive> boolean = tryParseBool(value);
        if (boolean) {
            return std::move(boolean);
        }
    }

    if (typeMask & android::ResTable_map::TYPE_INTEGER) {
        // Try parsing this as an integer.
        std::unique_ptr<BinaryPrimitive> integer = tryParseInt(value);
        if (integer) {
            return std::move(integer);
        }
    }

    const uint32_t floatMask = android::ResTable_map::TYPE_FLOAT
            | android::ResTable_map::TYPE_DIMENSION | android::ResTable_map::TYPE_FRACTION;
    if (typeMask & floatMask) {
        // Try parsing this as a float.
        std::unique_ptr<BinaryPrimitive> floatingPoint = tryParseFloat(value);
        if (floatingPoint) {
            if (typeMask & androidTypeToAttributeTypeMask(floatingPoint->value.dataType)) {
                return std::move(floatingPoint);
            }
        }
    }
    return {};
}

/**
 * We successively try to parse the string as a resource type that the Attribute
 * allows.
 */
std::unique_ptr<Item> parseItemForAttribute(
        const StringPiece16& str, const Attribute* attr,
        std::function<void(const ResourceName&)> onCreateReference) {
    const uint32_t typeMask = attr->typeMask;
    std::unique_ptr<Item> value = parseItemForAttribute(str, typeMask, onCreateReference);
    if (value) {
        return value;
    }

    if (typeMask & android::ResTable_map::TYPE_ENUM) {
        // Try parsing this as an enum.
        std::unique_ptr<BinaryPrimitive> enumValue = tryParseEnumSymbol(attr, str);
        if (enumValue) {
            return std::move(enumValue);
        }
    }

    if (typeMask & android::ResTable_map::TYPE_FLAGS) {
        // Try parsing this as a flag.
        std::unique_ptr<BinaryPrimitive> flagValue = tryParseFlagSymbol(attr, str);
        if (flagValue) {
            return std::move(flagValue);
        }
    }
    return {};
}

} // namespace ResourceUtils
} // namespace aapt