Fix decompression (emscripten-forge#40)

* Add decompression method

* Saving data into a temporary file, fix reading decompressed data

* Refactoring code

Author: AnastasiaSliusar

build_wasm.sh

@@ -88,6 +88,6 @@ emcc unpack.c -o $WASM_LIB/unpack.js \
     -s INITIAL_MEMORY=128MB \
     -s ENVIRONMENT=web \
     -s EXPORTED_RUNTIME_METHODS='["ccall", "cwrap", "getValue", "UTF8ToString", "wasmMemory"]' \
-    -s EXPORTED_FUNCTIONS="['_extract_archive', '_free_extracted_archive', '_malloc', '_free']"
+    -s EXPORTED_FUNCTIONS="['_extract', '_free_extracted_archive', '_malloc', '_free']"
 
 echo "Build completed successfully!"

src/index.ts

@@ -18,21 +18,21 @@ export const initUntarJS = async (): Promise<IUnpackJSAPI> => {
     decompressionOnly: boolean = false
   ): Promise<FilesData> => {
     /**Since WebAssembly, memory is accessed using pointers
-      and the first parameter of extract_archive method from unpack.c, which is Uint8Array of file data, should be a pointer
+      and the first parameter of extract method from unpack.c, which is Uint8Array of file data, should be a pointer
       so we have to allocate memory for file data
     **/
     let inputPtr: number | null = wasmModule._malloc(data.length);
     wasmModule.HEAPU8.set(data, inputPtr);
 
 
-    let resultPtr: number | null = wasmModule._extract_archive(
+    let resultPtr: number | null = wasmModule._extract(
       inputPtr,
       data.length,
       decompressionOnly
     );
     const files: FilesData = {};
     /**
-     * Since extract_archive returns a pointer that refers to an instance of the ExtractedArchive in unpack.c
+     * Since extract returns a pointer that refers to an instance of the ExtractedArchive in unpack.c
         typedef struct {
           FileData* files;
           size_t fileCount;
@@ -99,7 +99,6 @@ export const initUntarJS = async (): Promise<IUnpackJSAPI> => {
         dataPtr,
         dataSize
       );
-
       const fileDataCopy = fileData.slice(0);
       files[filename] = fileDataCopy;
     }
@@ -121,7 +120,7 @@ export const initUntarJS = async (): Promise<IUnpackJSAPI> => {
 
   const checkIsArchive = (url: string): boolean => {
     let isArchive: boolean = false;
-    let archiveExtArr = ['.conda', 'tar.bz2', 'tar.gz'];
+    let archiveExtArr = ['.conda', 'tar.bz2', 'tar.gz', '.zip'];
     archiveExtArr.forEach(type => {
       if (url.toLowerCase().endsWith(type)) {
         isArchive = true;

src/unpack.d.ts

@@ -5,7 +5,7 @@ export interface IWasmModule {
   HEAPU8: Uint8Array;
   _malloc(size: number): number;
   _free(ptr: number): void;
-  _extract_archive(
+  _extract(
     inputPtr: number,
     inputSize: number,
     decompressionOnly: boolean

unpack.c

@@ -19,14 +19,28 @@ typedef struct {
     char error_message[256];
 } ExtractedArchive;
 
+ExtractedArchive* error_handler(ExtractedArchive* result, const char *error_message, struct archive* archive) {
+
+    if (!result || !archive) {
+        fprintf(stderr, "Archive is null\n");
+        return NULL;
+    }
+
+    result->status = 0;
+
+    snprintf(result->error_message, sizeof(result->error_message), "%s", error_message);
+    archive_read_free(archive);
+    return result;
+}
 
 EMSCRIPTEN_KEEPALIVE
-ExtractedArchive* extract_archive(uint8_t* inputData, size_t inputSize, bool decompressionOnly ) {
+ExtractedArchive* extract_archive(uint8_t* inputData, size_t inputSize ) {
     struct archive* archive;
     struct archive_entry* entry;
     size_t files_struct_length = 100;
     FileData* files = NULL;
     size_t files_count = 0;
+    const char *error_message;
 
     ExtractedArchive* result = (ExtractedArchive*)malloc(sizeof(ExtractedArchive));
     if (!result) {
@@ -41,32 +55,24 @@ ExtractedArchive* extract_archive(uint8_t* inputData, size_t inputSize, bool dec
     archive = archive_read_new();
     archive_read_support_filter_all(archive);
     archive_read_support_format_all(archive);
-    if (decompressionOnly) {
-        archive_read_support_format_raw(archive);
-    }
 
     if (archive_read_open_memory(archive, inputData, inputSize) != ARCHIVE_OK) {
-        result->status = 0;
-        snprintf(result->error_message, sizeof(result->error_message), "%s", archive_error_string(archive));
-        archive_read_free(archive);
-        return result;
+        return error_handler(result,archive_error_string(archive), archive); 
     }
     files = malloc(sizeof(FileData) * files_struct_length);
 
     while (archive_read_next_header(archive, &entry) == ARCHIVE_OK) {
-        const char* filename =  decompressionOnly ? "decompression.json": archive_entry_pathname(entry);
-        size_t entrySize = decompressionOnly ? inputSize: archive_entry_size(entry);
+        const char* filename = archive_entry_pathname(entry);
+        size_t entrySize = archive_entry_size(entry);
         if (files_count + 1 > files_struct_length) {
             files_struct_length *= 2; // double the length
             FileData* oldfiles = files;
             files= realloc(files, sizeof(FileData) * files_struct_length);
             if (!files) {
-                archive_read_free(archive);
-                result->status = 0;
                 result->fileCount = files_count;
                 result->files = oldfiles; // otherwise memory is lost, alternatively also everything can be freed.
-                snprintf(result->error_message, sizeof(result->error_message), "Memory allocation error for file data.");
-                return result;
+                error_message = "Memory allocation error for file data.";
+                return error_handler(result, error_message, archive);
             }     
         }
         files[files_count].filename = strdup(filename);
@@ -75,13 +81,11 @@ ExtractedArchive* extract_archive(uint8_t* inputData, size_t inputSize, bool dec
 
         if (!files[files_count].data) {
             free(files[files_count].filename);
-            files[files_count].filename = NULL; 
-            archive_read_free(archive);
-            result->status = 0;
+            files[files_count].filename = NULL;
             result->fileCount = files_count;
             result->files = files; // otherwise memory is lost, alternatively also everything can be freed.
-            snprintf(result->error_message, sizeof(result->error_message), "Memory allocation error for file contents.");
-            return result;
+            error_message = "Memory allocation error for file contents.";
+            return error_handler(result, error_message, archive);
         }
 
         size_t bytesRead = 0;
@@ -94,10 +98,7 @@ ExtractedArchive* extract_archive(uint8_t* inputData, size_t inputSize, bool dec
                 }
                 free(files);
                 result->files = NULL;
-                result->status = 0;
-                snprintf(result->error_message, sizeof(result->error_message), "%s", archive_error_string(archive));
-                archive_read_free(archive);
-                return result;
+                return error_handler(result, archive_error_string(archive), archive);
             }
             bytesRead += ret;
         }
@@ -111,6 +112,142 @@ ExtractedArchive* extract_archive(uint8_t* inputData, size_t inputSize, bool dec
     return result;
 }
 
+char* write_to_temp_file(uint8_t* data, size_t size) {
+    char* temp_file_name = strdup("/tmp/decompressionXXXXXX");
+    int fd = mkstemp(temp_file_name);
+    if (fd == -1) {
+        perror("Failed to create temporary file for decompression file");
+        free(temp_file_name);
+        return NULL;
+    }
+
+    FILE* temp_file = fdopen(fd, "wb");
+    if (!temp_file) {
+        perror("Failed to open temporary file");
+        close(fd);
+        unlink(temp_file_name);
+        free(temp_file_name);
+        return NULL;
+    }
+
+    if (fwrite(data, 1, size, temp_file) != size) {
+        perror("Failed to write to temporary file");
+        fclose(temp_file);
+        unlink(temp_file_name);
+        free(temp_file_name);
+        return NULL;
+    }
+
+    fclose(temp_file);
+    return temp_file_name;
+}
+
+EMSCRIPTEN_KEEPALIVE
+ExtractedArchive* decompression(uint8_t* inputData, size_t inputSize) {
+    struct archive* archive;
+    struct archive_entry* entry;
+    size_t files_count = 0;
+
+    const size_t buffsize = 64 * 1024;
+    char buff[buffsize];
+    size_t total_size = 0; 
+    const char *error_message;
+
+    FileData* files = malloc(sizeof(FileData) * (files_count + 1));
+
+    if (!files) {
+        printf("Failed to allocate memory for files array\n");
+        return NULL;
+    }
+    
+    ExtractedArchive* result = (ExtractedArchive*)malloc(sizeof(ExtractedArchive));
+    if (!result) {
+        free(files);
+        return NULL;
+    }
+
+    result->files = NULL;
+    result->fileCount = 0;
+    result->status = 1;
+    result->error_message[0] = '\0';
+
+    char* temp_file_name = write_to_temp_file(inputData, inputSize);
+    if (!temp_file_name) {
+        free(files);
+        error_message = "Failed to create temporary file";
+        return error_handler(result, error_message, archive);
+    }
+
+    archive = archive_read_new();
+    archive_read_support_filter_all(archive);
+    archive_read_support_format_raw(archive);
+
+    if (archive_read_open_filename(archive, temp_file_name, inputSize) != ARCHIVE_OK) {
+        unlink(temp_file_name);
+        free(temp_file_name);
+        free(files);
+        return error_handler(result, archive_error_string(archive), archive);
+    }
+
+    while (archive_read_next_header(archive, &entry) == ARCHIVE_OK) {
+        const char* filename = archive_entry_pathname(entry);
+        if (!filename) filename = "decompression";
+
+        files[files_count].filename = strdup(filename);
+        files[files_count].data = NULL;
+        files[files_count].data_size = 0;
+
+        ssize_t ret;
+
+        for (;;) {
+            ret = archive_read_data(archive, buff, buffsize);
+            if (ret < 0) {
+                for (size_t i = 0; i <= files_count; i++) {
+                        free(files[i].filename);
+                        free(files[i].data);
+                    }
+                    free(files);
+                    result->files = NULL;
+                    return error_handler(result, archive_error_string(archive), archive);
+            }
+            if (ret == 0) {
+                break;
+            }
+
+            void* new_data = realloc(files[files_count].data, total_size + ret);
+            if (!new_data) {
+                free(files[files_count].data);
+                error_message = "Memory allocation error";
+                return error_handler(result, error_message, archive);
+            }
+
+            files[files_count].data = new_data;
+            memcpy(files[files_count].data + total_size, buff, ret);
+            total_size += ret;
+        }
+        files[files_count].data_size = total_size;
+        files_count++;
+    }
+
+    archive_read_free(archive);
+    unlink(temp_file_name);
+    free(temp_file_name);
+
+    result->files = files;
+    result->fileCount = files_count;
+    result->status =  1;
+    return result;
+}
+
+EMSCRIPTEN_KEEPALIVE
+ExtractedArchive* extract(uint8_t* inputData, size_t inputSize, bool decompressionOnly ) {
+    if (!decompressionOnly) {
+        return extract_archive(inputData, inputSize);
+    } else {
+        return decompression(inputData, inputSize);
+    }
+}
+
 EMSCRIPTEN_KEEPALIVE
 void free_extracted_archive(ExtractedArchive* archive) {
     if (!archive) {