Add snapshot compression support into d8.

I'm not bothering with compressing d8.js, since it makes no sense,
but it is also possible.

R=sgjesse@chromium.org

Review URL: http://codereview.chromium.org/7046027

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8217 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

SConstruct

@@ -807,6 +807,12 @@ D8_FLAGS = {
     'arch:arm': {
       'LINKFLAGS':   ARM_LINK_FLAGS
     },
+    'compress_startup_data:bz2': {
+      'CPPDEFINES':   ['COMPRESS_STARTUP_DATA_BZ2'],
+      'os:linux': {
+        'LIBS': ['bz2']
+      }
+    }
   },
   'msvc': {
     'all': {

src/d8.cc

@@ -26,8 +26,11 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
-#include <stdlib.h>
+#ifdef COMPRESS_STARTUP_DATA_BZ2
+#include <bzlib.h>
+#endif
 #include <errno.h>
+#include <stdlib.h>
 
 #include "v8.h"
 
@@ -483,7 +486,44 @@ void Shell::AddHistogramSample(void* histogram, int sample) {
 }
 
 
+#ifdef COMPRESS_STARTUP_DATA_BZ2
+class BZip2Decompressor : public v8::StartupDataDecompressor {
+ public:
+  virtual ~BZip2Decompressor() { }
+
+ protected:
+  virtual int DecompressData(char* raw_data,
+                             int* raw_data_size,
+                             const char* compressed_data,
+                             int compressed_data_size) {
+    ASSERT_EQ(v8::StartupData::kBZip2,
+              v8::V8::GetCompressedStartupDataAlgorithm());
+    unsigned int decompressed_size = *raw_data_size;
+    int result =
+        BZ2_bzBuffToBuffDecompress(raw_data,
+                                   &decompressed_size,
+                                   const_cast<char*>(compressed_data),
+                                   compressed_data_size,
+                                   0, 1);
+    if (result == BZ_OK) {
+      *raw_data_size = decompressed_size;
+    }
+    return result;
+  }
+};
+#endif
+
+
 void Shell::Initialize() {
+#ifdef COMPRESS_STARTUP_DATA_BZ2
+  BZip2Decompressor startup_data_decompressor;
+  int bz2_result = startup_data_decompressor.Decompress();
+  if (bz2_result != BZ_OK) {
+    fprintf(stderr, "bzip error code: %d\n", bz2_result);
+    exit(1);
+  }
+#endif
+
   Shell::counter_map_ = new CounterMap();
   // Set up counters
   if (i::StrLength(i::FLAG_map_counters) != 0)

src/d8.h

@@ -32,10 +32,6 @@
 #include "v8.h"
 #include "hashmap.h"
 
-#ifdef COMPRESS_STARTUP_DATA_BZ2
-#error Using compressed startup data is not supported for D8
-#endif
-
 namespace v8 {