Support adjusting the compression level through CCACHE_COMPRESS_LEVEL

4 files changed, 33 insertions, 21 deletions

diff --git a/MANUAL.txt b/MANUAL.txt
index f15d6667..b263c5a7 100644
--- a/MANUAL.txt
+++ b/MANUAL.txt
@@ -244,6 +244,13 @@ WRAPPERS>>.
     cache; compressed and uncompressed results will still be usable regardless
     of this setting.
 
+*CCACHE_COMPRESS_LEVEL*::
+
+    This environment variable determines the level at which ccache will
+    compress object files. It only has effect if *CCACHE_COMPRESS* is also
+    set. The value defaults to 6, and must be no lower than 1 (fastest, worst
+    compression) and no higher than 9 (slowest, best compression).
+
 *CCACHE_CPP2*::
 
     If you set the environment variable *CCACHE_CPP2* then ccache will not use
diff --git a/ccache.c b/ccache.c
index 2a956a5d..79421047 100644
--- a/ccache.c
+++ b/ccache.c
@@ -163,10 +163,10 @@ static bool enable_unify;
 static bool enable_direct = true;
 
 /*
- * Whether to enable compression of files stored in the cache. (Manifest files
- * are always compressed.)
+ * If non-zero, enables compression of files stored in the cache, compressed
+ * at the given level. (Manifest files are always compressed.)
  */
-static bool enable_compression = false;
+static int enable_compression = 0;
 
 /* number of levels (1 <= nlevels <= 8) */
 static int nlevels = 2;
@@ -2097,7 +2097,11 @@ ccache(int argc, char *argv[])
 
 	if (getenv("CCACHE_COMPRESS")) {
 		cc_log("Compression enabled");
-		enable_compression = true;
+		if (getenv("CCACHE_COMPRESS_LEVEL")) {
+			enable_compression = atoi(getenv("CCACHE_COMPRESS_LEVEL"));
+		} else {
+			enable_compression = 6;
+		}
 	}
 
 	if ((env = getenv("CCACHE_NLEVELS"))) {
diff --git a/ccache.h b/ccache.h
index 6a62753d..b9505ac3 100644
--- a/ccache.h
+++ b/ccache.h
@@ -102,10 +102,10 @@ void cc_log(const char *format, ...) ATTR_FORMAT(printf, 1, 2);
 void cc_log_argv(const char *prefix, char **argv);
 void fatal(const char *format, ...) ATTR_FORMAT(printf, 1, 2);
 void copy_fd(int fd_in, int fd_out);
-int copy_file(const char *src, const char *dest, int compress_dest);
-int move_file(const char *src, const char *dest, int compress_dest);
+int copy_file(const char *src, const char *dest, int compress_level);
+int move_file(const char *src, const char *dest, int compress_level);
 int move_uncompressed_file(const char *src, const char *dest,
-                           int compress_dest);
+                           int compress_level);
 bool file_is_compressed(const char *filename);
 int create_dir(const char *dir);
 int create_parent_dirs(const char *path);
diff --git a/util.c b/util.c
index e1f09bc5..bca11bc5 100644
--- a/util.c
+++ b/util.c
@@ -191,11 +191,11 @@ mkstemp(char *template)
 #endif
 
 /*
- * Copy src to dest, decompressing src if needed. compress_dest decides whether
- * dest will be compressed.
+ * Copy src to dest, decompressing src if needed. compress_level > 0 decides whether
+ * dest will be compressed, and with which compression level.
  */
 int
-copy_file(const char *src, const char *dest, int compress_dest)
+copy_file(const char *src, const char *dest, int compress_level)
 {
 	int fd_in = -1, fd_out = -1;
 	gzFile gz_in = NULL, gz_out = NULL;
@@ -210,7 +210,7 @@ copy_file(const char *src, const char *dest, int compress_dest)
 
 	tmp_name = format("%s.%s.XXXXXX", dest, tmp_string());
 	cc_log("Copying %s to %s via %s (%s)",
-	       src, dest, tmp_name, compress_dest ? "compressed": "uncompressed");
+	       src, dest, tmp_name, compress_level ? "compressed": "uncompressed");
 
 	/* open source file */
 	fd_in = open(src, O_RDONLY | O_BINARY);
@@ -233,7 +233,7 @@ copy_file(const char *src, const char *dest, int compress_dest)
 		goto error;
 	}
 
-	if (compress_dest) {
+	if (compress_level) {
 		/*
 		 * A gzip file occupies at least 20 bytes, so it will always
 		 * occupy an entire filesystem block, even for empty files.
@@ -244,20 +244,21 @@ copy_file(const char *src, const char *dest, int compress_dest)
 			goto error;
 		}
 		if (file_size(&st) == 0) {
-			compress_dest = 0;
+			compress_level = 0;
 		}
 	}
 
-	if (compress_dest) {
+	if (compress_level) {
 		gz_out = gzdopen(dup(fd_out), "wb");
 		if (!gz_out) {
 			cc_log("gzdopen(dest) error: %s", strerror(errno));
 			goto error;
 		}
+		gzsetparams(gz_out, compress_level, Z_DEFAULT_STRATEGY);
 	}
 
 	while ((n = gzread(gz_in, buf, sizeof(buf))) > 0) {
-		if (compress_dest) {
+		if (compress_level) {
 			written = gzwrite(gz_out, buf, n);
 		} else {
 			ssize_t count;
@@ -271,7 +272,7 @@ copy_file(const char *src, const char *dest, int compress_dest)
 			} while (written < n);
 		}
 		if (written != n) {
-			if (compress_dest) {
+			if (compress_level) {
 				cc_log("gzwrite error: %s (errno: %s)",
 				       gzerror(gz_in, &errnum),
 				       strerror(errno));
@@ -346,11 +347,11 @@ error:
 
 /* Run copy_file() and, if successful, delete the source file. */
 int
-move_file(const char *src, const char *dest, int compress_dest)
+move_file(const char *src, const char *dest, int compress_level)
 {
 	int ret;
 
-	ret = copy_file(src, dest, compress_dest);
+	ret = copy_file(src, dest, compress_level);
 	if (ret != -1) {
 		x_unlink(src);
 	}
@@ -362,10 +363,10 @@ move_file(const char *src, const char *dest, int compress_dest)
  * are on the same file system.
  */
 int
-move_uncompressed_file(const char *src, const char *dest, int compress_dest)
+move_uncompressed_file(const char *src, const char *dest, int compress_level)
 {
-	if (compress_dest) {
-		return move_file(src, dest, compress_dest);
+	if (compress_level) {
+		return move_file(src, dest, compress_level);
 	} else {
 		return x_rename(src, dest);
 	}