mirror of
https://github.com/0x5eal/luau-unzip.git
synced 2025-04-04 06:30:53 +01:00
refactor: small restructure and move utils outside main
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429EF1C337871656
3 changed files with 128 additions and 115 deletions
181
lib/init.luau
181
lib/init.luau
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@ -1,5 +1,6 @@
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local inflate = require("./inflate")
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local crc32 = require("./crc")
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local validateCrc = require("./utils/validate_crc")
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local path = require("./utils/path")
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-- Little endian constant signatures used in the ZIP file format
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local SIGNATURES = table.freeze({
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@ -13,27 +14,8 @@ local SIGNATURES = table.freeze({
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END_OF_CENTRAL_DIR = 0x06054b50,
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})
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type CrcValidationOptions = {
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skip: boolean,
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expected: number,
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}
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local function validateCrc(decompressed: buffer, validation: CrcValidationOptions)
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-- Unless skipping validation is requested, we verify the checksum
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if not validation.skip then
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local computed = crc32(decompressed)
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assert(
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validation.expected == computed,
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`Validation failed; CRC checksum does not match: {string.format("%x", computed)} ~= {string.format(
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"%x",
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computed
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)} (expected ~= got)`
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)
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end
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end
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export type CompressionMethod = "STORE" | "DEFLATE"
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local DECOMPRESSION_ROUTINES: { [number]: { name: CompressionMethod, decompress: (buffer, number, CrcValidationOptions) -> buffer } } =
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-- Decompression routines for each supported compression method
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local DECOMPRESSION_ROUTINES: { [number]: { name: CompressionMethod, decompress: (buffer, number, validateCrc.CrcValidationOptions) -> buffer } } =
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table.freeze({
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-- `STORE` decompression method - No compression
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[0x00] = {
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@ -57,6 +39,13 @@ local DECOMPRESSION_ROUTINES: { [number]: { name: CompressionMethod, decompress:
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},
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})
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local EMPTY_PROPERTIES: ZipEntryProperties = table.freeze({
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size = 0,
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attributes = 0,
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timestamp = 0,
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crc = 0,
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})
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-- TODO: ERROR HANDLING!
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local ZipEntry = {}
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@ -76,20 +65,14 @@ type ZipEntryInner = {
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children: { ZipEntry }, -- The children of the entry
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}
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type ZipEntryProperties = {
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export type CompressionMethod = "STORE" | "DEFLATE"
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export type ZipEntryProperties = {
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size: number,
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attributes: number,
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timestamp: number,
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method: CompressionMethod?,
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crc: number,
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}
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local EMPTY_PROPERTIES: ZipEntryProperties = table.freeze({
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size = 0,
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attributes = 0,
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timestamp = 0,
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method = nil,
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crc = 0,
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})
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function ZipEntry.new(offset: number, name: string, properties: ZipEntryProperties): ZipEntry
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return setmetatable(
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@ -232,7 +215,7 @@ function ZipReader.parseCentralDirectory(self: ZipReader): ()
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ZipEntry.new(offset, name, {
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size = size,
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crc = crc,
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method = DECOMPRESSION_ROUTINES[compressionMethod].name,
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method = DECOMPRESSION_ROUTINES[compressionMethod].name :: CompressionMethod,
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timestamp = timestamp,
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attributes = externalAttrs,
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isAscii = bit32.band(internalAttrs, 0x0001) ~= 0,
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@ -244,43 +227,43 @@ function ZipReader.parseCentralDirectory(self: ZipReader): ()
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end
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function ZipReader.buildDirectoryTree(self: ZipReader): ()
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-- Sort entries to process directories first; I could either handle
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-- directories and files in separate passes over the entries, or sort
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-- the entries so I handled the directories first -- I decided to do
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-- the latter
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table.sort(self.entries, function(a, b)
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if a.isDirectory ~= b.isDirectory then
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return a.isDirectory
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end
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return a.name < b.name
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end)
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-- Sort entries to process directories first; I could either handle
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-- directories and files in separate passes over the entries, or sort
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-- the entries so I handled the directories first -- I decided to do
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-- the latter
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table.sort(self.entries, function(a, b)
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if a.isDirectory ~= b.isDirectory then
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return a.isDirectory
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end
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return a.name < b.name
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end)
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for _, entry in self.entries do
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local parts = {}
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-- Split entry path into individual components
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-- e.g. "folder/subfolder/file.txt" -> {"folder", "subfolder", "file.txt"}
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for part in string.gmatch(entry.name, "([^/]+)/?") do
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table.insert(parts, part)
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end
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for _, entry in self.entries do
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local parts = {}
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-- Split entry path into individual components
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-- e.g. "folder/subfolder/file.txt" -> {"folder", "subfolder", "file.txt"}
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for part in string.gmatch(entry.name, "([^/]+)/?") do
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table.insert(parts, part)
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end
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-- Start from root directory
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local current = self.root
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local path = ""
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-- Start from root directory
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local current = self.root
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local path = ""
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-- Process each path component
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for i, part in parts do
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path ..= part
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-- Process each path component
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for i, part in parts do
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path ..= part
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if i < #parts or entry.isDirectory then
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-- Create missing directory entries for intermediate paths
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if not self.directories[path] then
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if entry.isDirectory and i == #parts then
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-- Existing directory entry, reuse it
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self.directories[path] = entry
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else
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-- Create new directory entry for intermediate paths or undefined
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-- parent directories in the ZIP
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local dir = ZipEntry.new(0, path .. "/", {
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if i < #parts or entry.isDirectory then
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-- Create missing directory entries for intermediate paths
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if not self.directories[path] then
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if entry.isDirectory and i == #parts then
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-- Existing directory entry, reuse it
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self.directories[path] = entry
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else
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-- Create new directory entry for intermediate paths or undefined
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-- parent directories in the ZIP
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local dir = ZipEntry.new(0, path .. "/", {
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size = 0,
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crc = 0,
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compressionMethod = "STORED",
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@ -290,22 +273,22 @@ function ZipReader.buildDirectoryTree(self: ZipReader): ()
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dir.isDirectory = true
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dir.parent = current
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self.directories[path] = dir
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end
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end
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-- Track directory in both lookup table and parent's children
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table.insert(current.children, self.directories[path])
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end
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-- Track directory in both lookup table and parent's children
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table.insert(current.children, self.directories[path])
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end
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-- Move deeper into the tree
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current = self.directories[path]
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continue
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end
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-- Move deeper into the tree
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current = self.directories[path]
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continue
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end
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-- Link file entry to its parent directory
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entry.parent = current
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table.insert(current.children, entry)
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end
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end
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-- Link file entry to its parent directory
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entry.parent = current
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table.insert(current.children, entry)
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end
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end
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end
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function ZipReader.findEntry(self: ZipReader, path: string): ZipEntry?
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@ -336,7 +319,7 @@ end
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type ExtractionOptions = {
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followSymlinks: boolean?,
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decompress: boolean?,
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isString: boolean?,
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isString: boolean?, -- TODO: Rename to isText or similar in breaking change
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skipCrcValidation: boolean?,
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skipSizeValidation: boolean?,
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}
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@ -448,54 +431,22 @@ function ZipReader.extract(self: ZipReader, entry: ZipEntry, options: Extraction
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skip = true,
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}))
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--- Canonicalize a path by removing redundant components
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local function canonicalize(path: string): string
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-- NOTE: It is fine for us to use `/` here because ZIP file names
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-- always use `/` as the path separator
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local components = string.split(path, "/")
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local result = {}
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for _, component in components do
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if component == "." then
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-- Skip current directory
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continue
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end
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if component == ".." then
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-- Traverse one upwards
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table.remove(result, #result)
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continue
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end
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-- Otherwise, add the component to the result
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table.insert(result, component)
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end
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return table.concat(result, "/")
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end
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-- Check if the path was a relative path
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if
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not (
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string.match(linkPath, "^/")
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or string.match(linkPath, "^[a-zA-Z]:[\\/]")
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or string.match(linkPath, "^//")
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)
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then
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if path.isRelative(linkPath) then
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if string.sub(linkPath, -1) ~= "/" then
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linkPath ..= "/"
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end
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linkPath = canonicalize(`{(entry.parent or self.root).name}{linkPath}`)
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linkPath = path.canonicalize(`{(entry.parent or self.root).name}{linkPath}`)
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end
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optionsOrDefault.followSymlinks = false
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optionsOrDefault.isString = false
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optionsOrDefault.skipCrcValidation = true
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optionsOrDefault.skipSizeValidation = true
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content = self:extract(
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self:findEntry(linkPath) or error("Symlink path not found"),
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optionsOrDefault
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) :: buffer
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content =
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self:extract(self:findEntry(linkPath) or error("Symlink path not found"), optionsOrDefault) :: buffer
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end
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content = algo.decompress(content, uncompressedSize, {
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40
lib/utils/path.luau
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40
lib/utils/path.luau
Normal file
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@ -0,0 +1,40 @@
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--- Canonicalize a path by removing redundant components
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local function canonicalize(path: string): string
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-- NOTE: It is fine for us to use `/` here because ZIP file names
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-- always use `/` as the path separator
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local components = string.split(path, "/")
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local result = {}
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for _, component in components do
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if component == "." then
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-- Skip current directory
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continue
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end
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if component == ".." then
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-- Traverse one upwards
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table.remove(result, #result)
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continue
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end
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-- Otherwise, add the component to the result
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table.insert(result, component)
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end
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return table.concat(result, "/")
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end
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--- Check if a path is absolute
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local function isAbsolute(path: string): boolean
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return (string.match(path, "^/") or string.match(path, "^[a-zA-Z]:[\\/]") or string.match(path, "^//")) ~= nil
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end
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--- Check if a path is relative
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local function isRelative(path: string): boolean
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return not isAbsolute(path)
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end
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return {
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canonicalize = canonicalize,
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isAbsolute = isAbsolute,
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isRelative = isRelative,
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}
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22
lib/utils/validate_crc.luau
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22
lib/utils/validate_crc.luau
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@ -0,0 +1,22 @@
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local crc32 = require("../crc")
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export type CrcValidationOptions = {
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skip: boolean,
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expected: number,
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}
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local function validateCrc(decompressed: buffer, validation: CrcValidationOptions)
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-- Unless skipping validation is requested, we verify the checksum
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if not validation.skip then
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local computed = crc32(decompressed)
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assert(
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validation.expected == computed,
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`Validation failed; CRC checksum does not match: {string.format("%x", computed)} ~= {string.format(
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"%x",
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computed
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)} (expected ~= got)`
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)
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end
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end
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return validateCrc
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