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Author SHA1 Message Date
Gleb Koval e7dd3fa073
Verify FSEntry name
Test Workflow / Lint and test library (pull_request) Successful in 1m42s Details
2024-01-07 15:04:13 +00:00
Gleb Koval 726980a669
Test create file & cleanup 2024-01-07 15:03:00 +00:00
Gleb Koval 8aa21dff54 Deny cyclic FSFolders (#3)
Test Workflow / Lint and test library (push) Successful in 3m56s Details
Contributes to #2 .

Handle cyclic folders explicitly, instead of relying on the filesystem.

Reviewed-on: #3
2024-01-07 14:56:16 +00:00
4 changed files with 135 additions and 36 deletions

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@ -1,36 +1,49 @@
package filesystem
import java.nio.file.FileAlreadyExistsException
import java.nio.file.FileSystemException
import java.nio.file.Files
import java.nio.file.Path
import kotlin.io.path.createDirectory
import kotlin.io.path.createFile
import kotlin.io.path.writeText
class FSCreator {
/**
* Create entry, leaving existing folders' contents, but overwriting existing files.
* @throws CyclicFolderException Cyclic folders cannot be created.
*/
@Throws(FileSystemException::class)
@Throws(CyclicFolderException::class)
fun create(
entryToCreate: FSEntry,
destination: String,
) {
val queue = ArrayDeque<Pair<FSEntry, Path>>()
queue.add(entryToCreate to Path.of(destination))
// No point in running anything if we know the input is invalid.
if (entryToCreate is FSFolder && entryToCreate.isCyclic()) {
throw CyclicFolderException()
}
val queue =
ArrayDeque(
listOf(
entryToCreate to Path.of(destination),
),
)
while (queue.isNotEmpty()) {
val (entry, dest) = queue.removeFirst()
val path = dest.resolve(entry.name)
try {
when (entry) {
is FSFile -> Files.createFile(path)
is FSFolder -> Files.createDirectory(path)
is FSFile -> path.createFile()
is FSFolder -> path.createDirectory()
}
} catch (_: FileAlreadyExistsException) {
} // Allow files/folders to already exist.
when (entry) {
is FSFile -> Files.write(path, entry.content.toByteArray())
is FSFile -> path.writeText(entry.content)
is FSFolder -> queue.addAll(entry.entries.map { it to path })
}
}
}
}
class CyclicFolderException : Exception("Cyclic FSFolders are not supported")

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@ -1,9 +1,39 @@
package filesystem
import kotlin.io.path.Path
// Note sealed allows for simpler logic in FSCreator by guaranteeing FSFile and FSFolder are the only possible FSEntries
// (as we expect), and it also implicitly makes the class abstract as required.
sealed class FSEntry(val name: String)
sealed class FSEntry(val name: String) {
init {
val p = Path(name)
// Only allow single filenames (no paths or relative references (e.g. ".."))
if (p.toList().size != 1 || p.fileName != p.toFile().canonicalFile.toPath().fileName) {
throw InvalidEntryNameException(name)
}
}
}
class FSFile(name: String, val content: String) : FSEntry(name)
class FSFolder(name: String, val entries: List<FSEntry>) : FSEntry(name)
class FSFolder(name: String, val entries: List<FSEntry>) : FSEntry(name) {
/**
* Check whether a folder is cyclic.
*/
fun isCyclic(): Boolean {
val seen = listOf(this).toHashSet<FSEntry>()
val queue = ArrayDeque(entries)
while (queue.isNotEmpty()) {
val entry = queue.removeFirst()
if (!seen.add(entry)) {
return true
}
if (entry is FSFolder) {
queue.addAll(entry.entries)
}
}
return false
}
}
class InvalidEntryNameException(name: String) : Exception("Invalid FSEntry name: '$name'")

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@ -1,10 +1,10 @@
package filesystem
import org.junit.jupiter.api.*
import java.nio.file.FileSystemException
import java.nio.file.Files
import java.nio.file.Path
import java.io.File
import java.util.concurrent.TimeUnit
import kotlin.io.path.Path
import kotlin.io.path.createDirectory
import kotlin.test.Test
import kotlin.test.assertEquals
@ -14,17 +14,26 @@ class FSCreatorTest {
@BeforeEach
fun `before each`() {
assertDoesNotThrow("should create _tmp directory") {
Files.createDirectory(Path.of("_tmp"))
Path("_tmp").createDirectory()
}
}
@AfterEach
fun `after each`() {
assertDoesNotThrow("should delete _tmp directory") {
deleteRecursive(Path.of("_tmp"))
File("_tmp").deleteRecursively()
}
}
@Test
fun `create file`() {
val file = FSFile("test.txt", "This is a file")
assertDoesNotThrow("should create file") {
creator.create(file, "_tmp")
}
assertEquals(file.content, File("_tmp/", file.name).readText())
}
@Test
fun `create entries`() {
val readme = FSFile("README", "Hello World!")
@ -62,10 +71,10 @@ class FSCreatorTest {
}
// If objects don't exist, these functions will throw anyway, so don't explicitly check for existence.
// Similarly, don't explicitly check if an object is a directory.
assertEquals(readme.content, Files.readString(Path.of("_tmp/folder", readme.name)))
assertEquals(gomod.content, Files.readString(Path.of("_tmp/folder", gomod.name)))
assertEquals(maingo.content, Files.readString(Path.of("_tmp/folder", maingo.name)))
assertEquals(helloworldgo.content, Files.readString(Path.of("_tmp/folder/utils", helloworldgo.name)))
assertEquals(readme.content, File("_tmp/folder", readme.name).readText())
assertEquals(gomod.content, File("_tmp/folder", gomod.name).readText())
assertEquals(maingo.content, File("_tmp/folder", maingo.name).readText())
assertEquals(helloworldgo.content, File("_tmp/folder/utils", helloworldgo.name).readText())
}
@Test
@ -81,7 +90,7 @@ class FSCreatorTest {
FSFile("hi", "hi"),
),
),
FSFolder("another-folder", listOf()),
FSFolder("folder", listOf()),
FSFile("1.txt", "One!"),
FSFile("2.txt", "Two!"),
),
@ -95,7 +104,7 @@ class FSCreatorTest {
"folder",
listOf(
FSFolder(
"another-folder",
"folder",
listOf(
FSFolder(
"secrets",
@ -112,30 +121,35 @@ class FSCreatorTest {
"_tmp",
)
}
assertEquals("hi", Files.readString(Path.of("_tmp/folder/sub-folder/hi")))
assertEquals("P4ssW0rd", Files.readString(Path.of("_tmp/folder/another-folder/secrets/secret")))
assertEquals("One is a good number", Files.readString(Path.of("_tmp/folder/1.txt")))
assertEquals("Two!", Files.readString(Path.of("_tmp/folder/2.txt")))
assertEquals("Three!", Files.readString(Path.of("_tmp/folder/3.txt")))
assertEquals("hi", File("_tmp/folder/sub-folder/hi").readText())
assertEquals("P4ssW0rd", File("_tmp/folder/folder/secrets/secret").readText())
assertEquals("One is a good number", File("_tmp/folder/1.txt").readText())
assertEquals("Two!", File("_tmp/folder/2.txt").readText())
assertEquals("Three!", File("_tmp/folder/3.txt").readText())
}
@Test
@Timeout(500, unit = TimeUnit.MILLISECONDS) // in case implementation starts trying to handle recursion
fun `create throws on recursive folder`() {
@Timeout(500, unit = TimeUnit.MILLISECONDS) // in case implementation starts trying to handle cyclic folders
fun `create throws on cyclic folder`() {
val files = mutableListOf<FSEntry>()
val folder = FSFolder("folder", files)
files.add(folder)
assertThrows<FileSystemException> {
assertThrows<CyclicFolderException> {
creator.create(folder, "_tmp")
}
}
}
fun deleteRecursive(path: Path) {
if (Files.isDirectory(path)) {
for (child in Files.list(path)) {
deleteRecursive(child)
@Test
@Timeout(500, unit = TimeUnit.MILLISECONDS)
fun `create throws on long cyclic folder`() {
val files = mutableListOf<FSEntry>()
val folder1 = FSFolder("folder", files)
val folder2 = FSFolder("folder2", listOf(folder1))
val folder3 = FSFolder("folder3", listOf(folder2))
val folder4 = FSFolder("folder4", listOf(folder3))
files.add(folder4)
assertThrows<CyclicFolderException> {
creator.create(folder4, "_tmp")
}
}
Files.delete(path)
}

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@ -0,0 +1,42 @@
package filesystem
import org.junit.jupiter.api.Test
import kotlin.test.assertFalse
import kotlin.test.assertTrue
class FSEntryTest {
@Test
fun `non-cyclic folder`() {
val folder =
FSFolder(
"folder",
listOf(
FSFolder("folder", listOf()),
FSFile("text.txt", "Hello!"),
),
)
assertFalse(folder.isCyclic())
}
@Test
fun `cyclic folder`() {
val files = mutableListOf<FSEntry>()
val folder = FSFolder("folder", files)
files.add(folder)
assertTrue(folder.isCyclic())
}
@Test
fun `long cyclic folder`() {
val files = mutableListOf<FSEntry>()
val folder1 = FSFolder("folder", files)
val folder2 = FSFolder("folder2", listOf(folder1))
val folder3 = FSFolder("folder3", listOf(folder2))
val folder4 = FSFolder("folder4", listOf(folder3))
files.add(folder4)
assertTrue(folder1.isCyclic())
assertTrue(folder2.isCyclic())
assertTrue(folder3.isCyclic())
assertTrue(folder4.isCyclic())
}
}