Branch support #7

Merged
cyclane merged 1 commits from branch-support into main 2024-01-10 12:21:26 +00:00
2 changed files with 74 additions and 6 deletions

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@ -1,5 +1,7 @@
package tinyvm package tinyvm
import java.util.TreeSet
class HashCollisionException(hash: String) : Exception("Different object types with identical hash '$hash'") class HashCollisionException(hash: String) : Exception("Different object types with identical hash '$hash'")
private class CommitTimeComparator : Comparator<Commit> { private class CommitTimeComparator : Comparator<Commit> {
@ -9,14 +11,49 @@ private class CommitTimeComparator : Comparator<Commit> {
): Int = (o1.timestamp.epochSecond - o2.timestamp.epochSecond).toInt() ): Int = (o1.timestamp.epochSecond - o2.timestamp.epochSecond).toInt()
} }
class Repository { private val commitTimeComparator = CommitTimeComparator()
private val commits = sortedSetOf(CommitTimeComparator())
private class Branch(val name: String, val commits: TreeSet<Commit>)
class Repository(initialBranch: String = "master") {
private var head = Branch(initialBranch, sortedSetOf(commitTimeComparator))
private val commits = mutableMapOf(initialBranch to head)
val branch: String
get() = head.name
val branches: Set<String>
get() = commits.keys
// Store all objects in one map like git does. This would simplify the data persistence implementation (if there was // Store all objects in one map like git does. This would simplify the data persistence implementation (if there was
// one) and allows for other objects to be added in the future without modifying the data persistence implementation // one) and allows for other objects to be added in the future without modifying the data persistence implementation
// at all. // at all.
private val objects = mutableMapOf<String, Object>() private val objects = mutableMapOf<String, Object>()
/**
* Create a new branch as a copy of the current branch.
* @param name New branch name.
* @param use Whether to switch to this branch.
*/
fun createBranch(
name: String,
use: Boolean = true,
) {
commits[name] =
Branch(
name,
head.commits.clone() as? TreeSet<Commit> ?: throw Exception("TreeSet.clone() unexpected result"),
)
if (use) useBranch(name)
}
/**
* Use (switch to) a branch.
*/
fun useBranch(name: String) {
head = commits[name] ?: throw BranchNotFoundException(name)
}
/** /**
* (Deep) get or put a commit object into the repository. * (Deep) get or put a commit object into the repository.
* This will also get or put all child trees and blobs. * This will also get or put all child trees and blobs.
@ -33,7 +70,7 @@ class Repository {
timestamp = commit.timestamp, timestamp = commit.timestamp,
) )
objects[hash] = newCommit objects[hash] = newCommit
commits.add(newCommit) head.commits.add(newCommit)
return newCommit return newCommit
} }
@ -45,12 +82,12 @@ class Repository {
/** /**
* List all commits. * List all commits.
*/ */
fun listCommits(): List<Commit> = commits.toList() fun listCommits(): List<Commit> = head.commits.toList()
/** /**
* Find commit. * Find commit.
*/ */
fun findCommit(predicate: (Commit) -> Boolean): Commit? = commits.find(predicate) fun findCommit(predicate: (Commit) -> Boolean): Commit? = head.commits.find(predicate)
/** /**
* Dump repository objects * Dump repository objects
@ -89,4 +126,6 @@ class Repository {
*/ */
private inline fun <reified T : Object> findObject(hash: String): T? = private inline fun <reified T : Object> findObject(hash: String): T? =
objects[hash]?.let { it as? T ?: throw HashCollisionException(hash) } objects[hash]?.let { it as? T ?: throw HashCollisionException(hash) }
} }
class BranchNotFoundException(name: String) : Exception("Branch '$name' does not exist")

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@ -118,6 +118,35 @@ internal class RepositoryTest {
assertEquals(null, repository.getCommit("00000000000000000000")) assertEquals(null, repository.getCommit("00000000000000000000"))
} }
@Test
fun `can create and use branch`() {
repository.commit(commits[0])
repository.commit(commits[1])
repository.commit(commits[2])
repository.createBranch("test-branch", use = false)
assertEquals("master", repository.branch)
repository.createBranch("test-branch-2")
assertEquals("test-branch-2", repository.branch)
assertEquals(setOf("master", "test-branch", "test-branch-2"), repository.branches)
assertEquals(commits.map { it.hash() }, repository.listCommits().map { it.hash() })
assertEquals(10, repository.dumpObjects().size)
}
@Test
fun `can commit to branch`() {
repository.commit(commits[0])
repository.createBranch("test-branch")
repository.commit(commits[1])
repository.createBranch("test-branch-2")
repository.commit(commits[2])
assertEquals(commits.map { it.hash() }, repository.listCommits().map { it.hash() })
repository.useBranch("test-branch")
assertEquals(commits.take(2).map { it.hash() }, repository.listCommits().map { it.hash() })
repository.useBranch("master")
assertEquals(commits.take(1).map { it.hash() }, repository.listCommits().map { it.hash() })
}
@Test @Test
fun `can display commit`() { fun `can display commit`() {
assertEquals( assertEquals(