feat(parse): handle long file names (#31)

src/parse.ts

@@ -37,11 +37,19 @@ export function parseTar<
 
   while (offset < buffer.byteLength - 512) {
     // File name (offset: 0 - length: 100)
-    const name = _readString(buffer, offset, 100);
+    let name = _readString(buffer, offset, 100);
     if (name.length === 0) {
       break;
     }
 
+    // Long file-name handling
+    if (nextExtendedHeader) {
+      const longName = nextExtendedHeader.path || nextExtendedHeader.linkpath;
+      if (longName) {
+        name = longName;
+      }
+    }
+
     // File mode (offset: 100 - length: 8)
     const mode = _readString(buffer, offset + 100, 8).trim();
 
@@ -62,25 +70,38 @@ export function parseTar<
 
     // File type (offset: 156 - length: 1)
     // prettier-ignore
-    const _type = _readString(buffer, offset + 156, 1) as keyof typeof tarItemTypeMap;
-    const type = tarItemTypeMap[_type];
-
-    // Extended headers
-    if (type === "extendedHeader" || type === "globalExtendedHeader") {
-      const headers = _parseExtendedHeaders(
-        new Uint8Array(buffer, offset + 512, size),
-      );
-      if (type === "extendedHeader") {
-        nextExtendedHeader = headers;
-      } else {
-        nextExtendedHeader = undefined;
-        globalExtendedHeader = {
-          ...globalExtendedHeader,
-          ...headers,
-        };
+    const _type = (_readString(buffer, offset + 156, 1) || "0") as keyof typeof tarItemTypeMap;
+    const type = tarItemTypeMap[_type] || _type;
+
+    // Special types
+    switch (type) {
+      // Extended headers for next entry
+      case "extendedHeader" /* x */:
+      case "globalExtendedHeader" /* g */: {
+        const headers = _parseExtendedHeaders(
+          new Uint8Array(buffer, offset + 512, size),
+        );
+        if (type === "extendedHeader") {
+          nextExtendedHeader = headers;
+        } else {
+          nextExtendedHeader = undefined;
+          globalExtendedHeader = {
+            ...globalExtendedHeader,
+            ...headers,
+          };
+        }
+        offset += seek;
+        continue;
       }
-      offset += seek;
-      continue;
+      // GNU tar long file names
+      case "gnuLongFileName" /* L */:
+      case "gnuOldLongFileName" /* N */:
+      case "gnuLongLinkName" /* K */: {
+        nextExtendedHeader = { path: _readString(buffer, offset + 512, size) };
+        offset += seek;
+        continue;
+      }
+      // No default
     }
 
     // Ustar indicator (offset: 257 - length: 6)

test/fixtures/in/long/[160]#---------------------------------------------------------------------------------------------------------------------------------------------------------#/file.txt

@@ -0,0 +1 @@
+long file

test/fixtures/in/long/[160]#---------------------------------------------------------------------------------------------------------------------------------------------------------#/link

@@ -0,0 +1 @@
+file.txt

test/parse.test.ts

@@ -91,13 +91,23 @@ describe("parse", () => {
           new URL(`fixtures/out/${format}.tar`, import.meta.url),
         );
         const parsed = await parseTar(blob);
-        const names = parsed.map((f) => f.name);
-        expect(names).toMatchObject([
-          "./",
-          "./foo.txt",
-          "./bar/",
-          "./bar/baz.txt",
-        ]);
+
+        const expectedFiles = ["./foo.txt", "./bar/baz.txt"];
+
+        // Long filenames
+        if (!["v7", "ustar"].includes(format)) {
+          expectedFiles.push(
+            `./long/[160]#${"-".repeat(153)}#/file.txt`,
+            `./long/[160]#${"-".repeat(153)}#/link`,
+          );
+        }
+
+        expect(
+          parsed
+            .filter((i) => i.type !== "directory")
+            .map((i) => i.name)
+            .sort(),
+        ).toMatchObject(expectedFiles.sort());
       });
     }
   });