Initial commit

internal/dlcache/dlcache.go

@@ -0,0 +1,93 @@
+/*
+ * LURE - Linux User REpository
+ * Copyright (C) 2023 Elara Musayelyan
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package dlcache
+
+import (
+	"context"
+	"crypto/sha1"
+	"encoding/hex"
+	"io"
+	"os"
+	"path/filepath"
+
+	"lure.sh/lure/internal/config"
+)
+
+// BasePath returns the base path of the download cache
+func BasePath(ctx context.Context) string {
+	return filepath.Join(config.GetPaths(ctx).CacheDir, "dl")
+}
+
+// New creates a new directory with the given ID in the cache.
+// If a directory with the same ID already exists,
+// it will be deleted before creating a new one.
+func New(ctx context.Context, id string) (string, error) {
+	h, err := hashID(id)
+	if err != nil {
+		return "", err
+	}
+	itemPath := filepath.Join(BasePath(ctx), h)
+
+	fi, err := os.Stat(itemPath)
+	if err == nil || (fi != nil && !fi.IsDir()) {
+		err = os.RemoveAll(itemPath)
+		if err != nil {
+			return "", err
+		}
+	}
+
+	err = os.MkdirAll(itemPath, 0o755)
+	if err != nil {
+		return "", err
+	}
+
+	return itemPath, nil
+}
+
+// Get checks if an entry with the given ID
+// already exists in the cache, and if so,
+// returns the directory and true. If it
+// does not exist, it returns an empty string
+// and false.
+func Get(ctx context.Context, id string) (string, bool) {
+	h, err := hashID(id)
+	if err != nil {
+		return "", false
+	}
+	itemPath := filepath.Join(BasePath(ctx), h)
+
+	_, err = os.Stat(itemPath)
+	if err != nil {
+		return "", false
+	}
+
+	return itemPath, true
+}
+
+// hashID hashes the input ID with SHA1
+// and returns the hex string of the hashed
+// ID.
+func hashID(id string) (string, error) {
+	h := sha1.New()
+	_, err := io.WriteString(h, id)
+	if err != nil {
+		return "", err
+	}
+	return hex.EncodeToString(h.Sum(nil)), nil
+}

internal/dlcache/dlcache_test.go

@@ -0,0 +1,76 @@
+/*
+ * LURE - Linux User REpository
+ * Copyright (C) 2023 Elara Musayelyan
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package dlcache_test
+
+import (
+	"context"
+	"crypto/sha1"
+	"encoding/hex"
+	"io"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"lure.sh/lure/internal/config"
+	"lure.sh/lure/internal/dlcache"
+)
+
+func init() {
+	dir, err := os.MkdirTemp("/tmp", "lure-dlcache-test.*")
+	if err != nil {
+		panic(err)
+	}
+	config.GetPaths(context.Background()).RepoDir = dir
+}
+
+func TestNew(t *testing.T) {
+	const id = "https://example.com"
+	dir, err := dlcache.New(id)
+	if err != nil {
+		t.Errorf("Expected no error, got %s", err)
+	}
+
+	exp := filepath.Join(dlcache.BasePath(), sha1sum(id))
+	if dir != exp {
+		t.Errorf("Expected %s, got %s", exp, dir)
+	}
+
+	fi, err := os.Stat(dir)
+	if err != nil {
+		t.Errorf("stat: expected no error, got %s", err)
+	}
+
+	if !fi.IsDir() {
+		t.Errorf("Expected cache item to be a directory")
+	}
+
+	dir2, ok := dlcache.Get(id)
+	if !ok {
+		t.Errorf("Expected Get() to return valid value")
+	}
+	if dir2 != dir {
+		t.Errorf("Expected %s from Get(), got %s", dir, dir2)
+	}
+}
+
+func sha1sum(id string) string {
+	h := sha1.New()
+	_, _ = io.WriteString(h, id)
+	return hex.EncodeToString(h.Sum(nil))
+}