Fix short reads in ContentReader::buffer()
The actual length of data read by `dap::Reader::read()` was not being correctly inspected.
Fixed, added test.
Bug identified by @kuafuwang.
Fixes #27
diff --git a/src/content_stream.cpp b/src/content_stream.cpp
index d528669..e7c6628 100644
--- a/src/content_stream.cpp
+++ b/src/content_stream.cpp
@@ -136,14 +136,15 @@
bytes -= buf.size();
while (bytes > 0) {
uint8_t chunk[256];
- auto c = std::min(sizeof(chunk), bytes);
- if (reader->read(chunk, c) <= 0) {
+ auto numWant = std::min(sizeof(chunk), bytes);
+ auto numGot = reader->read(chunk, numWant);
+ if (numGot == 0) {
return false;
}
- for (size_t i = 0; i < c; i++) {
+ for (size_t i = 0; i < numGot; i++) {
buf.push_back(chunk[i]);
}
- bytes -= c;
+ bytes -= numGot;
}
return true;
}
diff --git a/src/content_stream_test.cpp b/src/content_stream_test.cpp
index df29b2e..3e5d732 100644
--- a/src/content_stream_test.cpp
+++ b/src/content_stream_test.cpp
@@ -19,6 +19,27 @@
#include "gmock/gmock.h"
#include "gtest/gtest.h"
+#include <memory>
+
+namespace {
+
+// SingleByteReader wraps a dap::Reader to only provide a single byte for each
+// read() call, regardless of the number of bytes actually requested.
+class SingleByteReader : public virtual dap::Reader {
+ public:
+ SingleByteReader(std::unique_ptr<dap::Reader>&& inner)
+ : inner(std::move(inner)) {}
+
+ bool isOpen() override { return inner->isOpen(); }
+ void close() override { return inner->close(); }
+ size_t read(void* buffer, size_t) override { return inner->read(buffer, 1); };
+
+ private:
+ std::unique_ptr<dap::Reader> inner;
+};
+
+} // namespace
+
TEST(ContentStreamTest, Write) {
auto sb = dap::StringBuffer::create();
auto ptr = sb.get();
@@ -45,3 +66,18 @@
ASSERT_EQ(cs.read(), "Content payload number three");
ASSERT_EQ(cs.read(), "");
}
+
+TEST(ContentStreamTest, ShortRead) {
+ auto sb = dap::StringBuffer::create();
+ sb->write("Content-Length: 26\r\n\r\nContent payload number one");
+ sb->write("some unrecognised garbage");
+ sb->write("Content-Length: 26\r\n\r\nContent payload number two");
+ sb->write("some more unrecognised garbage");
+ sb->write("Content-Length: 28\r\n\r\nContent payload number three");
+ dap::ContentReader cs(
+ std::unique_ptr<SingleByteReader>(new SingleByteReader(std::move(sb))));
+ ASSERT_EQ(cs.read(), "Content payload number one");
+ ASSERT_EQ(cs.read(), "Content payload number two");
+ ASSERT_EQ(cs.read(), "Content payload number three");
+ ASSERT_EQ(cs.read(), "");
+}
