Merge mamaev

01-git/merge-mamaev/README.md

@@ -0,0 +1,7 @@
+# Merge tool for merge trees in this git-like kvs
+
+## usage
+Usage: ../../cmd/main.go <target_hash> <merged_hash> <comment>"
+
+## test
+To run test, execute command from tests readme from its directory

01-git/merge-mamaev/cmd/main.go

@@ -0,0 +1,87 @@
+package main
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"log"
+	"merge/internal/mergeTools"
+	"os"
+	"sort"
+	"strings"
+	"time"
+)
+
+func main() {
+	const RFC822 = "02 Jan 06 15:04 MST"
+
+	if len(os.Args) != 4 {
+		fmt.Println("Usage: ./merge-mamaev/cmd/main.go <target_hash> <merged_hash> <comment>")
+		os.Exit(1)
+	}
+
+	target := os.Args[1]
+	merged := os.Args[2]
+	comment := os.Args[3]
+	commit := mergeTools.MergeDirectories(target, merged, strings.Split(comment, "\n"))
+
+	sort.Strings(commit.Parent)
+
+	parentHash, err := CreateBlob(commit.Parent)
+	if err != nil {
+		log.Fatal("Cannot create file in this directory " + err.Error())
+		os.Exit(1)
+	}
+
+	newFileContent := append(commit.Content, fmt.Sprintf(".parent:\t%s", parentHash))
+	sort.Strings(newFileContent)
+
+	treeHash, err := CreateBlob(newFileContent)
+	loc, err := time.LoadLocation("Europe/Moscow")
+	if err != nil {
+		log.Fatal("Cannot load TimeZone " + err.Error())
+		os.Exit(1)
+	}
+	date := time.Now().In(loc)
+	//To prevent inconsistent state(tree with .commit file, but old hash in its name) need to create new tree refers to old
+	commitContent := []string{"Root: " + treeHash, "Date: " + date.Format(RFC822) + "\n", comment}
+
+	commitHash, err := CreateBlob(commitContent)
+	commitTreeContent := make([]string, 0)
+	for _, line := range newFileContent {
+		if strings.HasPrefix(line, ".parent") {
+			continue
+		}
+		commitTreeContent = append(commitTreeContent, line)
+
+	}
+
+	commitTreeContent = append(commitTreeContent, fmt.Sprintf(".parent:\t%s", treeHash), fmt.Sprintf(".commit:\t%s", commitHash))
+
+	sort.Strings(commitTreeContent)
+
+	result, err := CreateBlob(commitTreeContent)
+	if err != nil {
+		log.Fatal("cannot create merge tree " + err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Println("Merge successful. New tree hash:", result)
+}
+
+func CreateBlob(content []string) (string, error) {
+	hasher := sha256.New()
+	fileText := strings.Join(content, "\n")
+	hasher.Write([]byte(fileText))
+	hash := hex.EncodeToString(hasher.Sum(nil))
+
+	file, err := os.Create(hash)
+	if err != nil {
+		return "", err
+	}
+
+	file.Write([]byte(fileText))
+	defer file.Close()
+
+	return hash, nil
+}

01-git/merge-mamaev/go.mod

@@ -0,0 +1,3 @@
+module merge
+
+go 1.23.4

01-git/merge-mamaev/internal/mergeTools/merge.go

@@ -0,0 +1,251 @@
+package mergeTools
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+)
+
+func getParent(hash string) string {
+	file, err := os.ReadFile(hash)
+	if err != nil {
+		return ""
+	}
+	lines := strings.Split(string(file), "\n")
+	for _, line := range lines {
+		if !strings.HasPrefix(line, ".parent") {
+			continue
+		}
+		hash := strings.Split(line, "\t")[1]
+		return hash
+	}
+
+	return ""
+}
+
+func getDepth(hash string) int {
+	count := 0
+	parent := getParent(hash)
+	for parent != "" {
+		parent = getParent(parent)
+		count += 1
+	}
+	return count
+}
+
+func lca(oldHash, newHash string) string {
+	lenOld := getDepth(oldHash)
+	lenNew := getDepth(newHash)
+	for lenOld != lenNew {
+		if lenOld > lenNew {
+			oldHash = getParent(oldHash)
+			lenOld -= 1
+		} else {
+			newHash = getParent(newHash)
+			lenNew -= 1
+		}
+	}
+	for oldHash != newHash {
+		oldHash = getParent(oldHash)
+		newHash = getParent(newHash)
+	}
+
+	return oldHash
+}
+
+func MergeDirectories(targetHash, mergingHash string, comment []string) Commit {
+	mutual := lca(targetHash, mergingHash)
+	data, err := os.ReadFile(mutual)
+	if err != nil {
+		log.Fatal("Cannot read file of tree " + mutual)
+		os.Exit(1)
+	}
+	initial := make(map[string]string)
+	for _, line := range strings.Split(string(data), "\n") {
+		if strings.HasPrefix(line, ".parent") || strings.HasPrefix(line, ".commit") || len(line) == 0 {
+			continue
+		}
+		pair := getEntryAndHash(line)
+		initial[pair.Entry] = pair.Hash
+
+	}
+
+	a := getUpcomingChanges(targetHash, initial)
+	b := getUpcomingChanges(mergingHash, initial)
+
+	mutualChanges, err := makeMutualChanges(&a, &b)
+	if err != nil {
+		log.Fatal(err)
+		os.Exit(1)
+	}
+	content := formCommit(&mutualChanges, initial)
+
+	commit := Commit{Parent: []string{targetHash, mergingHash}, Comment: comment, Content: content}
+	return commit
+}
+
+func makeMutualChanges(target, merged *Changes) (Changes, error) {
+	deletedHashMap := make(map[EntryAndHashPair]int)
+	for _, pair := range merged.Deleted {
+		deletedHashMap[pair] = 1
+	}
+	for _, pair := range target.Deleted {
+		deletedHashMap[pair] = 1
+	}
+	deleted := make([]EntryAndHashPair, 0, len(deletedHashMap))
+	for eahp := range deletedHashMap {
+		deleted = append(deleted, eahp)
+	}
+
+	changedConflicts := make([][]EntryAndHashPair, 0)
+	changedHashMap := make(map[string]string)
+	for _, pair := range merged.Changed {
+		changedHashMap[pair.Entry] = pair.Hash
+	}
+	for _, pair := range target.Changed {
+		if existingHash, ok := changedHashMap[pair.Entry]; ok {
+			if existingHash == pair.Hash {
+				//If both trees have equal changes, IMHO there is no conflict
+				continue
+			}
+			changedConflicts = append(changedConflicts, []EntryAndHashPair{
+				{Entry: pair.Entry, Hash: existingHash}, pair})
+		} else {
+			changedHashMap[pair.Entry] = pair.Hash
+		}
+	}
+	changed := make([]EntryAndHashPair, 0, len(changedHashMap))
+	for eahp := range changedHashMap {
+		changed = append(changed, EntryAndHashPair{eahp, changedHashMap[eahp]})
+	}
+
+	addedConflicts := make([][]EntryAndHashPair, 0)
+	addedHashMap := make(map[string]string)
+	for _, pair := range merged.Added {
+		addedHashMap[pair.Entry] = pair.Hash
+	}
+	for _, pair := range target.Added {
+		if existingHash, ok := addedHashMap[pair.Entry]; ok {
+			if existingHash == pair.Hash {
+				//If both trees have equal changes, IMHO there is no conflict
+				continue
+			}
+			addedConflicts = append(addedConflicts, []EntryAndHashPair{
+				{Entry: pair.Entry, Hash: existingHash}, pair})
+		} else {
+			addedHashMap[pair.Entry] = pair.Hash
+		}
+	}
+	added := make([]EntryAndHashPair, 0, len(addedHashMap))
+	for eahp := range addedHashMap {
+		added = append(added, EntryAndHashPair{eahp, addedHashMap[eahp]})
+	}
+
+	if len(addedConflicts)+len(changedConflicts) > 0 {
+		fmt.Println(buildConflictMessage(&changedConflicts, &addedConflicts))
+		return Changes{}, errors.New("Fatal error in merge, aborting...")
+	}
+
+	return Changes{Deleted: deleted, Added: added, Changed: changed}, nil
+}
+
+func buildConflictMessage(changed, added *[][]EntryAndHashPair) string {
+	message := "Failed to merge: there was conflicts in following files\n\n"
+	if len(*changed) != 0 {
+		message += "files/directories concurrently modified:\n\n"
+		for _, item := range *changed {
+			message += fmt.Sprintf("\t%s -- merging [%s...] -> target [%s...]\n", item[0].Entry, item[0].Hash[0:8], item[1].Hash[0:8])
+		}
+	}
+	if len(*added) != 0 {
+		message += "files/directories concurrently added:\n\n"
+		for _, item := range *added {
+			message += fmt.Sprintf("\t%s -- merging [%s...] -> target [%s...]\n", item[0].Entry, item[0].Hash[0:8], item[1].Hash[0:8])
+		}
+	}
+	return message
+}
+
+func formCommit(changes *Changes, initial map[string]string) []string {
+
+	for _, pair := range changes.Deleted {
+		delete(initial, pair.Entry)
+	}
+
+	for _, pair := range changes.Changed {
+		initial[pair.Entry] = pair.Hash
+	}
+
+	for _, pair := range changes.Added {
+		initial[pair.Entry] = pair.Hash
+	}
+
+	final := make([]string, 0)
+	for key := range initial {
+		final = append(final, fmt.Sprintf("%s\t%s", key, initial[key]))
+	}
+	return final
+}
+
+func getUpcomingChanges(hash string, previous map[string]string) Changes {
+	data, err := os.ReadFile(hash)
+	if err != nil {
+		os.Exit(1)
+	}
+	deleted := make([]EntryAndHashPair, 0)
+	visited := make(map[string]int)
+
+	changed := make([]EntryAndHashPair, 0)
+
+	added := make([]EntryAndHashPair, 0)
+	for _, line := range strings.Split(string(data), "\n") {
+		if strings.HasPrefix(line, ".parent") || strings.HasPrefix(line, ".commit") || len(line) == 0 {
+			continue
+		}
+		pair := getEntryAndHash(line)
+		if previousHash, ok := previous[pair.Entry]; ok {
+			visited[pair.Entry] = 1
+			if pair.Hash == previousHash {
+				continue
+			} else {
+				changed = append(changed, pair)
+			}
+		} else {
+			added = append(added, pair)
+		}
+	}
+
+	for pKey := range previous {
+		if _, ok := visited[pKey]; ok {
+			continue
+		} else {
+			deleted = append(deleted, EntryAndHashPair{Entry: pKey, Hash: previous[pKey]})
+		}
+	}
+
+	return Changes{Deleted: deleted, Changed: changed, Added: added}
+}
+
+func getEntryAndHash(line string) EntryAndHashPair {
+	parts := strings.Split(line, "\t")
+	return EntryAndHashPair{Entry: parts[0], Hash: parts[1]}
+}
+
+type EntryAndHashPair struct {
+	Entry string
+	Hash  string
+}
+
+type Changes struct {
+	Deleted []EntryAndHashPair
+	Changed []EntryAndHashPair
+	Added   []EntryAndHashPair
+}
+
+type Commit struct {
+	Parent  []string
+	Comment []string
+	Content []string
+}

01-git/merge-mamaev/tests/added_conflicts/01ba4719c80b6fe911b091a7c05124b64eeece964e09c058ef8f9805daca546b

@@ -0,0 +1 @@
+

01-git/merge-mamaev/tests/added_conflicts/06111c6797d5e5932b792d0c3afdf13bc912ba44af806058bbca4770d8915305

@@ -0,0 +1 @@
+init

01-git/merge-mamaev/tests/added_conflicts/08d44d60bd3c2f808a126faaedee05528dae6616bd9552b576a9c0b6ca79e54d

@@ -0,0 +1,3 @@
+.parent:	63d648b2c27ee40ece8d540a8f686d2939289b5b5306503272732d60ca0b58e9
+a:	1d71bf03f7d96d1b94d9aad04e2852e6dfc00b4669a7a976bfe138d8062f60b3
+init:	06111c6797d5e5932b792d0c3afdf13bc912ba44af806058bbca4770d8915305

01-git/merge-mamaev/tests/added_conflicts/1c87b6727f523662df714f06a94ea27fa4d9050c38f4f7712bd4663ffbfdfa01

@@ -0,0 +1 @@
+some content

01-git/merge-mamaev/tests/added_conflicts/1d71bf03f7d96d1b94d9aad04e2852e6dfc00b4669a7a976bfe138d8062f60b3

@@ -0,0 +1 @@
+another content

01-git/merge-mamaev/tests/added_conflicts/63d648b2c27ee40ece8d540a8f686d2939289b5b5306503272732d60ca0b58e9

@@ -0,0 +1,2 @@
+.parent:	01ba4719c80b6fe911b091a7c05124b64eeece964e09c058ef8f9805daca546b
+init:	06111c6797d5e5932b792d0c3afdf13bc912ba44af806058bbca4770d8915305

01-git/merge-mamaev/tests/added_conflicts/README.md

@@ -0,0 +1,5 @@
+# test
+should trigger conflict error
+
+# Command line
+go run ../../cmd/main.go 08d44d60bd3c2f808a126faaedee05528dae6616bd9552b576a9c0b6ca79e54d cdd8158eceb414fd083017a95001c7579dcd56bd0bec24353c808d9cbf74d23e conflict

01-git/merge-mamaev/tests/added_conflicts/cdd8158eceb414fd083017a95001c7579dcd56bd0bec24353c808d9cbf74d23e

@@ -0,0 +1,3 @@
+.parent:	63d648b2c27ee40ece8d540a8f686d2939289b5b5306503272732d60ca0b58e9
+a:	1c87b6727f523662df714f06a94ea27fa4d9050c38f4f7712bd4663ffbfdfa01
+init:	06111c6797d5e5932b792d0c3afdf13bc912ba44af806058bbca4770d8915305

01-git/merge-mamaev/tests/changed_conflicts/01ba4719c80b6fe911b091a7c05124b64eeece964e09c058ef8f9805daca546b

@@ -0,0 +1 @@
+

01-git/merge-mamaev/tests/changed_conflicts/06111c6797d5e5932b792d0c3afdf13bc912ba44af806058bbca4770d8915305

@@ -0,0 +1 @@
+init

01-git/merge-mamaev/tests/changed_conflicts/1c87b6727f523662df714f06a94ea27fa4d9050c38f4f7712bd4663ffbfdfa01

@@ -0,0 +1 @@
+some content

01-git/merge-mamaev/tests/changed_conflicts/1d71bf03f7d96d1b94d9aad04e2852e6dfc00b4669a7a976bfe138d8062f60b3

@@ -0,0 +1 @@
+another content

01-git/merge-mamaev/tests/changed_conflicts/1de076ccfb9852469cdcf1ee37d3d64c31895738a68a51b22ee665e8c4c08a31

@@ -0,0 +1,3 @@
+.parent:	f543ebc6593b491e4e8e0635a210b8b7f5428e99b9db82d5ad4d0f9617ff692e
+a:	1c87b6727f523662df714f06a94ea27fa4d9050c38f4f7712bd4663ffbfdfa01
+init:	06111c6797d5e5932b792d0c3afdf13bc912ba44af806058bbca4770d8915305

01-git/merge-mamaev/tests/changed_conflicts/84c0cb0fab5288dd86df9d45eaad9f19998afa3d235e4ae37d871e9a04e4881e

@@ -0,0 +1,3 @@
+.parent:	f543ebc6593b491e4e8e0635a210b8b7f5428e99b9db82d5ad4d0f9617ff692e
+a:	1d71bf03f7d96d1b94d9aad04e2852e6dfc00b4669a7a976bfe138d8062f60b3
+init:	06111c6797d5e5932b792d0c3afdf13bc912ba44af806058bbca4770d8915305

01-git/merge-mamaev/tests/changed_conflicts/README.md

@@ -0,0 +1,4 @@
+# test
+should trigger conflict error (files concurrently modified)
+# Command line
+go run ../../cmd/main.go 1de076ccfb9852469cdcf1ee37d3d64c31895738a68a51b22ee665e8c4c08a31 84c0cb0fab5288dd86df9d45eaad9f19998afa3d235e4ae37d871e9a04e4881e conflict

01-git/merge-mamaev/tests/changed_conflicts/d52672e78f66bdcdb511da750a09b44ba3e0f807b8d2dd1383a998bf9607d537

@@ -0,0 +1 @@
+initial content