Merge "BrotliDecompressionSource: don't bail out too early" into main

src/libutil/compression.cc

@@ -163,23 +163,24 @@ struct BrotliDecompressionSource : Source
         uint8_t * out = (uint8_t *) data;
         const auto * begin = out;
 
-        try {
+        while (len && !BrotliDecoderIsFinished(state.get())) {
-            while (len && !BrotliDecoderIsFinished(state.get())) {
+            checkInterrupt();
-                checkInterrupt();
 
-                while (avail_in == 0) {
+            while (avail_in == 0) {
+                try {
                     avail_in = inner->read(buf.get(), BUF_SIZE);
-                    next_in = (const uint8_t *) buf.get();
+                } catch (EndOfFile &) {
-                }
+                    break;
-
-                if (!BrotliDecoderDecompressStream(
-                        state.get(), &avail_in, &next_in, &len, &out, nullptr
-                    ))
-                {
-                    throw CompressionError("error while decompressing brotli file");
                 }
+                next_in = (const uint8_t *) buf.get();
+            }
+
+            if (!BrotliDecoderDecompressStream(
+                    state.get(), &avail_in, &next_in, &len, &out, nullptr
+                ))
+            {
+                throw CompressionError("error while decompressing brotli file");
             }
-        } catch (EndOfFile &) {
         }
 
         if (begin != out) {

tests/unit/libutil/compression.cc

@@ -66,6 +66,16 @@ namespace nix {
         ASSERT_THROW(decompress(method, str), CompressionError);
     }
 
+    TEST(decompress, veryLongBrotli) {
+        auto method = "br";
+        auto str = std::string(65536, 'a');
+        auto o = decompress(method, compress(method, str));
+
+        // This is just to not print 64k of "a" for most failures
+        ASSERT_EQ(o.length(), str.length());
+        ASSERT_EQ(o, str);
+    }
+
     /* ----------------------------------------------------------------------------
      * compression sinks
      * --------------------------------------------------------------------------*/