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Author: google-labs-jules[bot]

compressor/compress.go

@@ -0,0 +1,211 @@
+package lzw
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"file-compressor/constants"
+	"file-compressor/utils"
+)
+
+// Zip compresses a single file using LZW algorithm and writes to the output writer.
+// It writes metadata for the file (name length, name, data length, data).
+// The progressCallback expects (percentOfCurrentFile float64, messageFromZip string).
+func Zip(file utils.FileData, output io.Writer, progressCallback func(percentOfCurrentFile float64, messageFromZip string)) error {
+	if progressCallback != nil {
+		// Initial message for this specific file
+		progressCallback(0.0, fmt.Sprintf("Starting LZW for %s", filepath.Base(file.Name)))
+	}
+
+	if file.Reader == nil {
+		if file.Size > 0 {
+			utils.ColorPrint(utils.YELLOW, fmt.Sprintf("Warning: LZW Zip skipping '%s' due to nil reader.\n", file.Name))
+		}
+		// If reader is nil, we can't proceed.
+        // Report 100% for this "skipped" file to allow overall progress to advance.
+        if progressCallback != nil {
+            progressCallback(1.0, fmt.Sprintf("Skipped %s (nil reader)", filepath.Base(file.Name)))
+        }
+		return nil
+	}
+
+	fileReader := file.Reader
+
+	defer func(r io.Reader) {
+		if c, ok := r.(io.Closer); ok {
+			c.Close()
+		}
+	}(fileReader)
+
+	fileNameBytes := []byte(filepath.Base(file.Name))
+	if err := binary.Write(output, binary.LittleEndian, uint32(len(fileNameBytes))); err != nil {
+		return fmt.Errorf("LZW Zip: failed to write file name length for %s: %w", file.Name, err)
+	}
+
+	if _, err := output.Write(fileNameBytes); err != nil {
+		return fmt.Errorf("LZW Zip: failed to write file name for %s: %w", file.Name, err)
+	}
+
+	tempCompressedData := utils.NewResizableBuffer()
+
+    var bytesReadForThisFile int64
+    onProgressUpdate := func(readBytes int64, totalBytes int64) {
+        bytesReadForThisFile = readBytes
+        if progressCallback != nil && totalBytes > 0 {
+            percent := float64(readBytes) / float64(totalBytes)
+            if percent > 1.0 { percent = 1.0 } // Cap percent at 1.0
+            progressCallback(percent, fmt.Sprintf("Processing %s", filepath.Base(file.Name)))
+        }
+    }
+
+    trackingReader := utils.NewProgressReader(fileReader, file.Size, onProgressUpdate)
+
+	errCompress := compressData(trackingReader, tempCompressedData)
+	if errCompress != nil {
+		return fmt.Errorf("LZW Zip: failed to compress data for %s: %w", file.Name, errCompress)
+	}
+
+	// After compression, all bytes of this file should have been read (or an error occurred).
+    // Ensure a final 100% progress for this file is signaled if no error.
+    if progressCallback != nil && file.Size > 0 {
+        // Check if the last report was already 100%
+        // This might be redundant if compressData + ProgressTrackingReader already guarantees a final 100% call,
+        // but it's a safeguard.
+        currentProgress := 0.0
+        if file.Size > 0 { // Avoid division by zero if file.Size is 0
+            currentProgress = float64(bytesReadForThisFile) / float64(file.Size)
+        }
+        if currentProgress < 1.0 {
+            progressCallback(1.0, fmt.Sprintf("Finalizing %s", filepath.Base(file.Name)))
+        }
+    }
+
+
+	compressedSize := uint64(tempCompressedData.Len())
+	if err := binary.Write(output, binary.LittleEndian, compressedSize); err != nil {
+		return fmt.Errorf("LZW Zip: failed to write compressed data length for %s: %w", file.Name, err)
+	}
+
+	if _, err := io.Copy(output, tempCompressedData.Reader()); err != nil {
+		return fmt.Errorf("LZW Zip: failed to write compressed data for %s: %w", file.Name, err)
+	}
+
+	if progressCallback != nil {
+		// Final confirmation for this specific file being done.
+		progressCallback(1.0, fmt.Sprintf("Finished LZW for %s", filepath.Base(file.Name)))
+	}
+	return nil
+}
+
+// Unzip decompresses data using LZW algorithm from the input reader and writes to outputDir.
+func Unzip(input io.Reader, outputDir string, progressCallback utils.ProgressCallback) ([]string, error) {
+	if progressCallback != nil {
+		// This is a general progress callback, not the fine-grained one.
+        // We'd need to adapt Unzip similarly to provide detailed progress.
+        // For now, just initial and final messages based on the old system.
+		// Example of how it might be adapted later:
+        // utils.UpdateProgress(utils.ProgressInfo{OriginalMessage: "Starting LZW decompression..."}, progressCallback)
+		progressCallback(0.0, "Starting LZW decompression...")
+	}
+	var decompressedFiles []string
+	fileIndex := 0
+
+	for {
+		fileIndex++
+		var fileNameLen uint32
+		err := binary.Read(input, binary.LittleEndian, &fileNameLen)
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return decompressedFiles, fmt.Errorf("LZW Unzip: failed to read file name length (file #%d): %w", fileIndex, err)
+		}
+
+		if fileNameLen == 0 || fileNameLen > 1024*1024 {
+             return decompressedFiles, fmt.Errorf("LZW Unzip: invalid file name length %d (file #%d), archive might be corrupted", fileNameLen, fileIndex)
+        }
+
+		fileNameBytes := make([]byte, fileNameLen)
+		if _, err := io.ReadFull(input, fileNameBytes); err != nil {
+			return decompressedFiles, fmt.Errorf("LZW Unzip: failed to read file name (file #%d): %w", fileIndex, err)
+		}
+		fileName := string(fileNameBytes)
+        cleanFileName := filepath.Clean(fileName)
+
+        if strings.HasPrefix(cleanFileName, ".."+string(filepath.Separator)) || cleanFileName == ".." || strings.HasPrefix(cleanFileName, string(filepath.Separator)) || strings.Contains(fileName, "\\") || strings.Contains(fileName, ":") {
+            utils.ColorPrint(utils.RED, fmt.Sprintf("Warning: LZW Unzip potentially unsafe file path '%s' in archive. Skipping.\n", fileName))
+            var compressedSizeToSkip uint64
+            if errSize := binary.Read(input, binary.LittleEndian, &compressedSizeToSkip); errSize != nil {
+                 return decompressedFiles, fmt.Errorf("LZW Unzip: failed to read size for potentially unsafe file %s: %w", fileName, errSize)
+            }
+            if _, errSeek := io.CopyN(io.Discard, input, int64(compressedSizeToSkip)); errSeek != nil {
+                 return decompressedFiles, fmt.Errorf("LZW Unzip: failed to skip data for potentially unsafe file %s: %w", fileName, errSeek)
+            }
+            // TODO: Report progress for skipped file if possible, e.g.
+            // if progressCallback != nil { utils.UpdateProgress(utils.ProgressInfo{ ... CurrentFileName: fileName, OriginalMessage: "Skipped unsafe file" ... }, progressCallback) }
+            continue
+        }
+		filePath := filepath.Join(outputDir, cleanFileName)
+
+		if err := os.MkdirAll(filepath.Dir(filePath), 0755); err != nil {
+			return decompressedFiles, fmt.Errorf("LZW Unzip: failed to create directory for %s: %w", filePath, err)
+		}
+
+		var compressedSize uint64
+		if err := binary.Read(input, binary.LittleEndian, &compressedSize); err != nil {
+			return decompressedFiles, fmt.Errorf("LZW Unzip: failed to read compressed data length for %s: %w", fileName, err)
+		}
+
+		outFile, createErr := os.Create(filePath)
+		if createErr != nil {
+			return decompressedFiles, fmt.Errorf("LZW Unzip: %s for %s: %w", constants.FILE_CREATE_ERROR, filePath, createErr)
+		}
+
+		successfulDecompression := false
+		defer func(file *os.File, path string) {
+			file.Close()
+			if !successfulDecompression {
+				os.Remove(path)
+			}
+		}(outFile, filePath)
+
+		if compressedSize == 0 {
+            successfulDecompression = true
+            decompressedFiles = append(decompressedFiles, filePath)
+            if progressCallback != nil {
+				// This is an approximation of overall progress, not ideal for the new system
+				progress := float64(fileIndex) / (float64(fileIndex) + 1.0)
+                // Example: utils.UpdateProgress(utils.ProgressInfo{ ... CurrentFileName: fileName, OriginalMessage: "Decompressed empty file" ... }, progressCallback)
+				progressCallback(progress, fmt.Sprintf("Decompressed %s (empty)", fileName))
+            }
+            continue
+        }
+
+		limitedReader := io.LimitReader(input, int64(compressedSize))
+        // TODO: Wrap limitedReader with utils.NewProgressReader for decompressData if we want byte-level progress for decompression
+		errDecompress := decompressData(limitedReader, outFile)
+
+		if errDecompress != nil {
+			return decompressedFiles, fmt.Errorf("LZW Unzip: failed to decompress data for %s: %w", fileName, errDecompress)
+		}
+		successfulDecompression = true
+
+		decompressedFiles = append(decompressedFiles, filePath)
+		if progressCallback != nil {
+			// Approximation
+			progress := float64(fileIndex) / (float64(fileIndex) + 1.0)
+            // Example: utils.UpdateProgress(utils.ProgressInfo{ ... CurrentFileName: fileName, OriginalMessage: "Decompressed file" ... }, progressCallback)
+			progressCallback(progress, fmt.Sprintf("Decompressed %s", fileName))
+		}
+	}
+
+	if progressCallback != nil {
+		// Example: utils.UpdateProgress(utils.ProgressInfo{OriginalMessage: "LZW decompression completed.", OverallProcessedBytes: totalArchiveSize, OverallTotalBytes: totalArchiveSize}, progressCallback)
+		progressCallback(1.0, "LZW decompression completed.")
+	}
+	return decompressedFiles, nil
+}