Properly use RAII to reduce complication

native/jni/magiskboot/bootimg.cpp

@@ -28,9 +28,10 @@ static void decompress(format_t type, int fd, const void *in, size_t size) {
 
 static int64_t compress(format_t type, int fd, const void *in, size_t size) {
 	auto prev = lseek(fd, 0, SEEK_CUR);
-	unique_ptr<stream> ptr(get_encoder(type, open_stream<fd_stream>(fd)));
-	ptr->write(in, size);
-	ptr->close();
+	{
+		unique_ptr<stream> ptr(get_encoder(type, open_stream<fd_stream>(fd)));
+		ptr->write(in, size);
+	}
 	auto now = lseek(fd, 0, SEEK_CUR);
 	return now - prev;
 }

native/jni/magiskboot/compress.cpp

@@ -22,7 +22,6 @@
 using namespace std;
 
 #define bwrite filter_stream::write
-#define bclose filter_stream::close
 
 constexpr size_t CHUNK = 0x40000;
 constexpr size_t LZ4_UNCOMPRESSED = 0x800000;
@@ -35,26 +34,26 @@ public:
 	int read(void *buf, size_t len) final {
 		return stream::read(buf, len);
 	}
-
-	int close() final {
-		finish();
-		return bclose();
-	}
-
-protected:
-	// If finish is overridden, destroy should be called in the destructor
-	virtual void finish() {}
-	void destroy() { if (fp) finish(); }
 };
 
 class gz_strm : public cpr_stream {
 public:
-	~gz_strm() override { destroy(); }
-
 	int write(const void *buf, size_t len) override {
 		return len ? write(buf, len, Z_NO_FLUSH) : 0;
 	}
 
+	~gz_strm() override {
+		write(nullptr, 0, Z_FINISH);
+		switch(mode) {
+			case DECODE:
+				inflateEnd(&strm);
+				break;
+			case ENCODE:
+				deflateEnd(&strm);
+				break;
+		}
+	}
+
 protected:
 	enum mode_t {
 		DECODE,
@@ -72,18 +71,6 @@ protected:
 		}
 	}
 
-	void finish() override {
-		write(nullptr, 0, Z_FINISH);
-		switch(mode) {
-			case DECODE:
-				inflateEnd(&strm);
-				break;
-			case ENCODE:
-				deflateEnd(&strm);
-				break;
-		}
-	}
-
 private:
 	z_stream strm;
 	uint8_t outbuf[CHUNK];
@@ -125,12 +112,22 @@ public:
 
 class bz_strm : public cpr_stream {
 public:
-	~bz_strm() override { destroy(); }
-
 	int write(const void *buf, size_t len) override {
 		return len ? write(buf, len, BZ_RUN) : 0;
 	}
 
+	~bz_strm() override {
+		switch(mode) {
+			case DECODE:
+				BZ2_bzDecompressEnd(&strm);
+				break;
+			case ENCODE:
+				write(nullptr, 0, BZ_FINISH);
+				BZ2_bzCompressEnd(&strm);
+				break;
+		}
+	}
+
 protected:
 	enum mode_t {
 		DECODE,
@@ -148,18 +145,6 @@ protected:
 		}
 	}
 
-	void finish() override {
-		switch(mode) {
-			case DECODE:
-				BZ2_bzDecompressEnd(&strm);
-				break;
-			case ENCODE:
-				write(nullptr, 0, BZ_FINISH);
-				BZ2_bzCompressEnd(&strm);
-				break;
-		}
-	}
-
 private:
 	bz_stream strm;
 	char outbuf[CHUNK];
@@ -201,12 +186,15 @@ public:
 
 class lzma_strm : public cpr_stream {
 public:
-	~lzma_strm() override { destroy(); }
-
 	int write(const void *buf, size_t len) override {
 		return len ? write(buf, len, LZMA_RUN) : 0;
 	}
 
+	~lzma_strm() override {
+		write(nullptr, 0, LZMA_FINISH);
+		lzma_end(&strm);
+	}
+
 protected:
 	enum mode_t {
 		DECODE,
@@ -238,11 +226,6 @@ protected:
 		}
 	}
 
-	void finish() override {
-		write(nullptr, 0, LZMA_FINISH);
-		lzma_end(&strm);
-	}
-
 private:
 	lzma_stream strm;
 	uint8_t outbuf[CHUNK];
@@ -266,17 +249,17 @@ private:
 
 class lzma_decoder : public lzma_strm {
 public:
-	lzma_decoder(FILE *fp) : lzma_strm(DECODE, fp) {}
+	explicit lzma_decoder(FILE *fp) : lzma_strm(DECODE, fp) {}
 };
 
 class xz_encoder : public lzma_strm {
 public:
-	xz_encoder(FILE *fp) : lzma_strm(ENCODE_XZ, fp) {}
+	explicit xz_encoder(FILE *fp) : lzma_strm(ENCODE_XZ, fp) {}
 };
 
 class lzma_encoder : public lzma_strm {
 public:
-	lzma_encoder(FILE *fp) : lzma_strm(ENCODE_LZMA, fp) {}
+	explicit lzma_encoder(FILE *fp) : lzma_strm(ENCODE_LZMA, fp) {}
 };
 
 class LZ4F_decoder : public cpr_stream {
@@ -340,12 +323,6 @@ public:
 		LZ4F_createCompressionContext(&ctx, LZ4F_VERSION);
 	}
 
-	~LZ4F_encoder() override {
-		destroy();
-		LZ4F_freeCompressionContext(ctx);
-		delete[] outbuf;
-	}
-
 	int write(const void *buf, size_t len) override {
 		auto ret = len;
 		if (!outbuf)
@@ -368,10 +345,11 @@ public:
 		return ret;
 	}
 
-protected:
-	void finish() override {
+	~LZ4F_encoder() override {
 		size_t len = LZ4F_compressEnd(ctx, outbuf, outCapacity, nullptr);
 		bwrite(outbuf, len);
+		LZ4F_freeCompressionContext(ctx);
+		delete[] outbuf;
 	}
 
 private:
@@ -466,12 +444,6 @@ public:
 	: cpr_stream(fp), outbuf(new char[LZ4_COMPRESSED]), buf(new char[LZ4_UNCOMPRESSED]),
 	init(false), buf_off(0), in_total(0) {}
 
-	~LZ4_encoder() override {
-		destroy();
-		delete[] outbuf;
-		delete[] buf;
-	}
-
 	int write(const void *in, size_t size) override {
 		if (!init) {
 			bwrite("\x02\x21\x4c\x18", 4);
@@ -510,14 +482,15 @@ public:
 		return true;
 	}
 
-protected:
-	void finish() override {
+	~LZ4_encoder() override {
 		if (buf_off) {
 			int write = LZ4_compress_HC(buf, outbuf, buf_off, LZ4_COMPRESSED, 9);
 			bwrite(&write, sizeof(write));
 			bwrite(outbuf, write);
 		}
 		bwrite(&in_total, sizeof(in_total));
+		delete[] outbuf;
+		delete[] buf;
 	}
 
 private:
@@ -608,7 +581,7 @@ void decompress(char *infile, const char *outfile) {
 			LOGE("Decompression error!\n");
 	}
 
-	strm->close();
+	strm.reset(nullptr);
 	fclose(in_fp);
 
 	if (rm_in)
@@ -651,7 +624,7 @@ void compress(const char *method, const char *infile, const char *outfile) {
 			LOGE("Compression error!\n");
 	};
 
-	strm->close();
+	strm.reset(nullptr);
 	fclose(in_fp);
 
 	if (rm_in)

native/jni/utils/include/stream.h

@@ -18,7 +18,6 @@ public:
 	virtual int read(void *buf, size_t len);
 	virtual int write(const void *buf, size_t len);
 	virtual off_t seek(off_t off, int whence);
-	virtual int close();
 	virtual ~stream() = default;
 };
 
@@ -26,11 +25,10 @@ public:
 class filter_stream : public stream {
 public:
 	filter_stream(FILE *fp) : fp(fp) {}
-	~filter_stream() override { if (fp) close(); }
+	~filter_stream() override;
 
 	int read(void *buf, size_t len) override;
 	int write(const void *buf, size_t len) override;
-	int close() override;
 
 	void set_base(FILE *f);
 	template <class T, class... Args >

native/jni/utils/stream.cpp

@@ -19,9 +19,8 @@ static fpos_t strm_seek(void *v, fpos_t off, int whence) {
 
 static int strm_close(void *v) {
 	auto strm = reinterpret_cast<stream *>(v);
-	int ret = strm->close();
 	delete strm;
-	return ret;
+	return 0;
 }
 
 FILE *open_stream(stream *strm) {
@@ -46,8 +45,8 @@ off_t stream::seek(off_t off, int whence) {
 	return -1;
 }
 
-int stream::close() {
-	return 0;
+filter_stream::~filter_stream() {
+	if (fp) fclose(fp);
 }
 
 int filter_stream::read(void *buf, size_t len) {
@@ -58,12 +57,6 @@ int filter_stream::write(const void *buf, size_t len) {
 	return fwrite(buf, 1, len, fp);
 }
 
-int filter_stream::close() {
-	int ret = fclose(fp);
-	fp = nullptr;
-	return ret;
-}
-
 void filter_stream::set_base(FILE *f) {
 	if (fp) fclose(fp);
 	fp = f;