xref: /llvm-project/llvm/unittests/DebugInfo/MSF/MappedBlockStreamTest.cpp (revision 018338e503880ac56457692ad2dee3c38945d629)
1 //===- llvm/unittest/DebugInfo/MSF/MappedBlockStreamTest.cpp --------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "llvm/DebugInfo/MSF/MappedBlockStream.h"
11 #include "llvm/DebugInfo/MSF/IMSFFile.h"
12 #include "llvm/DebugInfo/MSF/MSFError.h"
13 #include "llvm/Support/BinaryByteStream.h"
14 #include "llvm/Support/BinaryStreamReader.h"
15 #include "llvm/Support/BinaryStreamRef.h"
16 #include "llvm/Support/BinaryStreamWriter.h"
17 #include "llvm/Testing/Support/Error.h"
18 
19 #include "gtest/gtest.h"
20 
21 #include <unordered_map>
22 
23 using namespace llvm;
24 using namespace llvm::msf;
25 using namespace llvm::support;
26 
27 namespace {
28 
29 static const uint32_t BlocksAry[] = {0, 1, 2, 5, 4, 3, 6, 7, 8, 9};
30 static uint8_t DataAry[] = {'A', 'B', 'C', 'F', 'E', 'D', 'G', 'H', 'I', 'J'};
31 
32 class DiscontiguousStream : public WritableBinaryStream {
33 public:
34   DiscontiguousStream(ArrayRef<uint32_t> Blocks, MutableArrayRef<uint8_t> Data)
35       : Blocks(Blocks.begin(), Blocks.end()), Data(Data.begin(), Data.end()) {}
36 
37   uint32_t block_size() const { return 1; }
38   uint32_t block_count() const { return Blocks.size(); }
39 
40   endianness getEndian() const override { return little; }
41 
42   Error readBytes(uint32_t Offset, uint32_t Size,
43                   ArrayRef<uint8_t> &Buffer) override {
44     if (auto EC = checkOffset(Offset, Size))
45       return EC;
46     Buffer = Data.slice(Offset, Size);
47     return Error::success();
48   }
49 
50   Error readLongestContiguousChunk(uint32_t Offset,
51                                    ArrayRef<uint8_t> &Buffer) override {
52     if (auto EC = checkOffset(Offset, 1))
53       return EC;
54     Buffer = Data.drop_front(Offset);
55     return Error::success();
56   }
57 
58   uint32_t getLength() override { return Data.size(); }
59 
60   Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> SrcData) override {
61     if (auto EC = checkOffset(Offset, SrcData.size()))
62       return EC;
63     ::memcpy(&Data[Offset], SrcData.data(), SrcData.size());
64     return Error::success();
65   }
66   Error commit() override { return Error::success(); }
67 
68   MSFStreamLayout layout() const {
69     return MSFStreamLayout{static_cast<uint32_t>(Data.size()), Blocks};
70   }
71 
72   BumpPtrAllocator Allocator;
73 
74 private:
75   std::vector<support::ulittle32_t> Blocks;
76   MutableArrayRef<uint8_t> Data;
77 };
78 
79 TEST(MappedBlockStreamTest, NumBlocks) {
80   DiscontiguousStream F(BlocksAry, DataAry);
81   auto S = MappedBlockStream::createStream(F.block_size(), F.layout(), F,
82                                            F.Allocator);
83   EXPECT_EQ(F.block_size(), S->getBlockSize());
84   EXPECT_EQ(F.layout().Blocks.size(), S->getNumBlocks());
85 }
86 
87 // Tests that a read which is entirely contained within a single block works
88 // and does not allocate.
89 TEST(MappedBlockStreamTest, ReadBeyondEndOfStreamRef) {
90   DiscontiguousStream F(BlocksAry, DataAry);
91   auto S = MappedBlockStream::createStream(F.block_size(), F.layout(), F,
92                                            F.Allocator);
93 
94   BinaryStreamReader R(*S);
95   BinaryStreamRef SR;
96   EXPECT_THAT_ERROR(R.readStreamRef(SR, 0U), Succeeded());
97   ArrayRef<uint8_t> Buffer;
98   EXPECT_THAT_ERROR(SR.readBytes(0U, 1U, Buffer), Failed());
99   EXPECT_THAT_ERROR(R.readStreamRef(SR, 1U), Succeeded());
100   EXPECT_THAT_ERROR(SR.readBytes(1U, 1U, Buffer), Failed());
101 }
102 
103 // Tests that a read which outputs into a full destination buffer works and
104 // does not fail due to the length of the output buffer.
105 TEST(MappedBlockStreamTest, ReadOntoNonEmptyBuffer) {
106   DiscontiguousStream F(BlocksAry, DataAry);
107   auto S = MappedBlockStream::createStream(F.block_size(), F.layout(), F,
108                                            F.Allocator);
109 
110   BinaryStreamReader R(*S);
111   StringRef Str = "ZYXWVUTSRQPONMLKJIHGFEDCBA";
112   EXPECT_THAT_ERROR(R.readFixedString(Str, 1), Succeeded());
113   EXPECT_EQ(Str, StringRef("A"));
114   EXPECT_EQ(0U, F.Allocator.getBytesAllocated());
115 }
116 
117 // Tests that a read which crosses a block boundary, but where the subsequent
118 // blocks are still contiguous in memory to the previous block works and does
119 // not allocate memory.
120 TEST(MappedBlockStreamTest, ZeroCopyReadContiguousBreak) {
121   DiscontiguousStream F(BlocksAry, DataAry);
122   auto S = MappedBlockStream::createStream(F.block_size(), F.layout(), F,
123                                            F.Allocator);
124   BinaryStreamReader R(*S);
125   StringRef Str;
126   EXPECT_THAT_ERROR(R.readFixedString(Str, 2), Succeeded());
127   EXPECT_EQ(Str, StringRef("AB"));
128   EXPECT_EQ(0U, F.Allocator.getBytesAllocated());
129 
130   R.setOffset(6);
131   EXPECT_THAT_ERROR(R.readFixedString(Str, 4), Succeeded());
132   EXPECT_EQ(Str, StringRef("GHIJ"));
133   EXPECT_EQ(0U, F.Allocator.getBytesAllocated());
134 }
135 
136 // Tests that a read which crosses a block boundary and cannot be referenced
137 // contiguously works and allocates only the precise amount of bytes
138 // requested.
139 TEST(MappedBlockStreamTest, CopyReadNonContiguousBreak) {
140   DiscontiguousStream F(BlocksAry, DataAry);
141   auto S = MappedBlockStream::createStream(F.block_size(), F.layout(), F,
142                                            F.Allocator);
143   BinaryStreamReader R(*S);
144   StringRef Str;
145   EXPECT_THAT_ERROR(R.readFixedString(Str, 10), Succeeded());
146   EXPECT_EQ(Str, StringRef("ABCDEFGHIJ"));
147   EXPECT_EQ(10U, F.Allocator.getBytesAllocated());
148 }
149 
150 // Test that an out of bounds read which doesn't cross a block boundary
151 // fails and allocates no memory.
152 TEST(MappedBlockStreamTest, InvalidReadSizeNoBreak) {
153   DiscontiguousStream F(BlocksAry, DataAry);
154   auto S = MappedBlockStream::createStream(F.block_size(), F.layout(), F,
155                                            F.Allocator);
156   BinaryStreamReader R(*S);
157   StringRef Str;
158 
159   R.setOffset(10);
160   EXPECT_THAT_ERROR(R.readFixedString(Str, 1), Failed());
161   EXPECT_EQ(0U, F.Allocator.getBytesAllocated());
162 }
163 
164 // Test that an out of bounds read which crosses a contiguous block boundary
165 // fails and allocates no memory.
166 TEST(MappedBlockStreamTest, InvalidReadSizeContiguousBreak) {
167   DiscontiguousStream F(BlocksAry, DataAry);
168   auto S = MappedBlockStream::createStream(F.block_size(), F.layout(), F,
169                                            F.Allocator);
170   BinaryStreamReader R(*S);
171   StringRef Str;
172 
173   R.setOffset(6);
174   EXPECT_THAT_ERROR(R.readFixedString(Str, 5), Failed());
175   EXPECT_EQ(0U, F.Allocator.getBytesAllocated());
176 }
177 
178 // Test that an out of bounds read which crosses a discontiguous block
179 // boundary fails and allocates no memory.
180 TEST(MappedBlockStreamTest, InvalidReadSizeNonContiguousBreak) {
181   DiscontiguousStream F(BlocksAry, DataAry);
182   auto S = MappedBlockStream::createStream(F.block_size(), F.layout(), F,
183                                            F.Allocator);
184   BinaryStreamReader R(*S);
185   StringRef Str;
186 
187   EXPECT_THAT_ERROR(R.readFixedString(Str, 11), Failed());
188   EXPECT_EQ(0U, F.Allocator.getBytesAllocated());
189 }
190 
191 // Tests that a read which is entirely contained within a single block but
192 // beyond the end of a StreamRef fails.
193 TEST(MappedBlockStreamTest, ZeroCopyReadNoBreak) {
194   DiscontiguousStream F(BlocksAry, DataAry);
195   auto S = MappedBlockStream::createStream(F.block_size(), F.layout(), F,
196                                            F.Allocator);
197   BinaryStreamReader R(*S);
198   StringRef Str;
199   EXPECT_THAT_ERROR(R.readFixedString(Str, 1), Succeeded());
200   EXPECT_EQ(Str, StringRef("A"));
201   EXPECT_EQ(0U, F.Allocator.getBytesAllocated());
202 }
203 
204 // Tests that a read which is not aligned on the same boundary as a previous
205 // cached request, but which is known to overlap that request, shares the
206 // previous allocation.
207 TEST(MappedBlockStreamTest, UnalignedOverlappingRead) {
208   DiscontiguousStream F(BlocksAry, DataAry);
209   auto S = MappedBlockStream::createStream(F.block_size(), F.layout(), F,
210                                            F.Allocator);
211   BinaryStreamReader R(*S);
212   StringRef Str1;
213   StringRef Str2;
214   EXPECT_THAT_ERROR(R.readFixedString(Str1, 7), Succeeded());
215   EXPECT_EQ(Str1, StringRef("ABCDEFG"));
216   EXPECT_EQ(7U, F.Allocator.getBytesAllocated());
217 
218   R.setOffset(2);
219   EXPECT_THAT_ERROR(R.readFixedString(Str2, 3), Succeeded());
220   EXPECT_EQ(Str2, StringRef("CDE"));
221   EXPECT_EQ(Str1.data() + 2, Str2.data());
222   EXPECT_EQ(7U, F.Allocator.getBytesAllocated());
223 }
224 
225 // Tests that a read which is not aligned on the same boundary as a previous
226 // cached request, but which only partially overlaps a previous cached request,
227 // still works correctly and allocates again from the shared pool.
228 TEST(MappedBlockStreamTest, UnalignedOverlappingReadFail) {
229   DiscontiguousStream F(BlocksAry, DataAry);
230   auto S = MappedBlockStream::createStream(F.block_size(), F.layout(), F,
231                                            F.Allocator);
232   BinaryStreamReader R(*S);
233   StringRef Str1;
234   StringRef Str2;
235   EXPECT_THAT_ERROR(R.readFixedString(Str1, 6), Succeeded());
236   EXPECT_EQ(Str1, StringRef("ABCDEF"));
237   EXPECT_EQ(6U, F.Allocator.getBytesAllocated());
238 
239   R.setOffset(4);
240   EXPECT_THAT_ERROR(R.readFixedString(Str2, 4), Succeeded());
241   EXPECT_EQ(Str2, StringRef("EFGH"));
242   EXPECT_EQ(10U, F.Allocator.getBytesAllocated());
243 }
244 
245 TEST(MappedBlockStreamTest, WriteBeyondEndOfStream) {
246   static uint8_t Data[] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J'};
247   static uint8_t LargeBuffer[] = {'0', '1', '2', '3', '4', '5',
248                                   '6', '7', '8', '9', 'A'};
249   static uint8_t SmallBuffer[] = {'0', '1', '2'};
250   static_assert(sizeof(LargeBuffer) > sizeof(Data),
251                 "LargeBuffer is not big enough");
252 
253   DiscontiguousStream F(BlocksAry, Data);
254   auto S = WritableMappedBlockStream::createStream(F.block_size(), F.layout(),
255                                                    F, F.Allocator);
256   ArrayRef<uint8_t> Buffer;
257 
258   EXPECT_THAT_ERROR(S->writeBytes(0, ArrayRef<uint8_t>(LargeBuffer)), Failed());
259   EXPECT_THAT_ERROR(S->writeBytes(0, ArrayRef<uint8_t>(SmallBuffer)),
260                     Succeeded());
261   EXPECT_THAT_ERROR(S->writeBytes(7, ArrayRef<uint8_t>(SmallBuffer)),
262                     Succeeded());
263   EXPECT_THAT_ERROR(S->writeBytes(8, ArrayRef<uint8_t>(SmallBuffer)), Failed());
264 }
265 
266 TEST(MappedBlockStreamTest, TestWriteBytesNoBreakBoundary) {
267   static uint8_t Data[] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J'};
268   DiscontiguousStream F(BlocksAry, Data);
269   auto S = WritableMappedBlockStream::createStream(F.block_size(), F.layout(),
270                                                    F, F.Allocator);
271   ArrayRef<uint8_t> Buffer;
272 
273   EXPECT_THAT_ERROR(S->readBytes(0, 1, Buffer), Succeeded());
274   EXPECT_EQ(Buffer, ArrayRef<uint8_t>('A'));
275   EXPECT_THAT_ERROR(S->readBytes(9, 1, Buffer), Succeeded());
276   EXPECT_EQ(Buffer, ArrayRef<uint8_t>('J'));
277 
278   EXPECT_THAT_ERROR(S->writeBytes(0, ArrayRef<uint8_t>('J')), Succeeded());
279   EXPECT_THAT_ERROR(S->writeBytes(9, ArrayRef<uint8_t>('A')), Succeeded());
280 
281   EXPECT_THAT_ERROR(S->readBytes(0, 1, Buffer), Succeeded());
282   EXPECT_EQ(Buffer, ArrayRef<uint8_t>('J'));
283   EXPECT_THAT_ERROR(S->readBytes(9, 1, Buffer), Succeeded());
284   EXPECT_EQ(Buffer, ArrayRef<uint8_t>('A'));
285 
286   EXPECT_THAT_ERROR(S->writeBytes(0, ArrayRef<uint8_t>('A')), Succeeded());
287   EXPECT_THAT_ERROR(S->writeBytes(9, ArrayRef<uint8_t>('J')), Succeeded());
288 
289   EXPECT_THAT_ERROR(S->readBytes(0, 1, Buffer), Succeeded());
290   EXPECT_EQ(Buffer, ArrayRef<uint8_t>('A'));
291   EXPECT_THAT_ERROR(S->readBytes(9, 1, Buffer), Succeeded());
292   EXPECT_EQ(Buffer, ArrayRef<uint8_t>('J'));
293 }
294 
295 TEST(MappedBlockStreamTest, TestWriteBytesBreakBoundary) {
296   static uint8_t Data[] = {'0', '0', '0', '0', '0', '0', '0', '0', '0', '0'};
297   static uint8_t TestData[] = {'T', 'E', 'S', 'T', 'I', 'N', 'G', '.'};
298   static uint8_t Expected[] = {'T', 'E', 'S', 'N', 'I',
299                                'T', 'G', '.', '0', '0'};
300 
301   DiscontiguousStream F(BlocksAry, Data);
302   auto S = WritableMappedBlockStream::createStream(F.block_size(), F.layout(),
303                                                    F, F.Allocator);
304   ArrayRef<uint8_t> Buffer;
305 
306   EXPECT_THAT_ERROR(S->writeBytes(0, TestData), Succeeded());
307   // First just compare the memory, then compare the result of reading the
308   // string out.
309   EXPECT_EQ(ArrayRef<uint8_t>(Data), ArrayRef<uint8_t>(Expected));
310 
311   EXPECT_THAT_ERROR(S->readBytes(0, 8, Buffer), Succeeded());
312   EXPECT_EQ(Buffer, ArrayRef<uint8_t>(TestData));
313 }
314 
315 TEST(MappedBlockStreamTest, TestWriteThenRead) {
316   std::vector<uint8_t> DataBytes(10);
317   MutableArrayRef<uint8_t> Data(DataBytes);
318   const uint32_t Blocks[] = {2, 1, 0, 6, 3, 4, 5, 7, 9, 8};
319 
320   DiscontiguousStream F(Blocks, Data);
321   auto S = WritableMappedBlockStream::createStream(F.block_size(), F.layout(),
322                                                    F, F.Allocator);
323 
324   enum class MyEnum : uint32_t { Val1 = 2908234, Val2 = 120891234 };
325   using support::ulittle32_t;
326 
327   uint16_t u16[] = {31468, 0};
328   uint32_t u32[] = {890723408, 0};
329   MyEnum Enum[] = {MyEnum::Val1, MyEnum::Val2};
330   StringRef ZStr[] = {"Zero Str", ""};
331   StringRef FStr[] = {"Fixed Str", ""};
332   uint8_t byteArray0[] = {'1', '2'};
333   uint8_t byteArray1[] = {'0', '0'};
334   ArrayRef<uint8_t> byteArrayRef0(byteArray0);
335   ArrayRef<uint8_t> byteArrayRef1(byteArray1);
336   ArrayRef<uint8_t> byteArray[] = {byteArrayRef0, byteArrayRef1};
337   uint32_t intArr0[] = {890723408, 29082234};
338   uint32_t intArr1[] = {890723408, 29082234};
339   ArrayRef<uint32_t> intArray[] = {intArr0, intArr1};
340 
341   BinaryStreamReader Reader(*S);
342   BinaryStreamWriter Writer(*S);
343   EXPECT_THAT_ERROR(Writer.writeInteger(u16[0]), Succeeded());
344   EXPECT_THAT_ERROR(Reader.readInteger(u16[1]), Succeeded());
345   EXPECT_EQ(u16[0], u16[1]);
346   EXPECT_EQ(std::vector<uint8_t>({0, 0x7A, 0xEC, 0, 0, 0, 0, 0, 0, 0}),
347             DataBytes);
348 
349   Reader.setOffset(0);
350   Writer.setOffset(0);
351   ::memset(DataBytes.data(), 0, 10);
352   EXPECT_THAT_ERROR(Writer.writeInteger(u32[0]), Succeeded());
353   EXPECT_THAT_ERROR(Reader.readInteger(u32[1]), Succeeded());
354   EXPECT_EQ(u32[0], u32[1]);
355   EXPECT_EQ(std::vector<uint8_t>({0x17, 0x5C, 0x50, 0, 0, 0, 0x35, 0, 0, 0}),
356             DataBytes);
357 
358   Reader.setOffset(0);
359   Writer.setOffset(0);
360   ::memset(DataBytes.data(), 0, 10);
361   EXPECT_THAT_ERROR(Writer.writeEnum(Enum[0]), Succeeded());
362   EXPECT_THAT_ERROR(Reader.readEnum(Enum[1]), Succeeded());
363   EXPECT_EQ(Enum[0], Enum[1]);
364   EXPECT_EQ(std::vector<uint8_t>({0x2C, 0x60, 0x4A, 0, 0, 0, 0, 0, 0, 0}),
365             DataBytes);
366 
367   Reader.setOffset(0);
368   Writer.setOffset(0);
369   ::memset(DataBytes.data(), 0, 10);
370   EXPECT_THAT_ERROR(Writer.writeCString(ZStr[0]), Succeeded());
371   EXPECT_THAT_ERROR(Reader.readCString(ZStr[1]), Succeeded());
372   EXPECT_EQ(ZStr[0], ZStr[1]);
373   EXPECT_EQ(
374       std::vector<uint8_t>({'r', 'e', 'Z', ' ', 'S', 't', 'o', 'r', 0, 0}),
375       DataBytes);
376 
377   Reader.setOffset(0);
378   Writer.setOffset(0);
379   ::memset(DataBytes.data(), 0, 10);
380   EXPECT_THAT_ERROR(Writer.writeFixedString(FStr[0]), Succeeded());
381   EXPECT_THAT_ERROR(Reader.readFixedString(FStr[1], FStr[0].size()),
382                     Succeeded());
383   EXPECT_EQ(FStr[0], FStr[1]);
384   EXPECT_EQ(
385       std::vector<uint8_t>({'x', 'i', 'F', 'd', ' ', 'S', 'e', 't', 0, 'r'}),
386       DataBytes);
387 
388   Reader.setOffset(0);
389   Writer.setOffset(0);
390   ::memset(DataBytes.data(), 0, 10);
391   EXPECT_THAT_ERROR(Writer.writeArray(byteArray[0]), Succeeded());
392   EXPECT_THAT_ERROR(Reader.readArray(byteArray[1], byteArray[0].size()),
393                     Succeeded());
394   EXPECT_EQ(byteArray[0], byteArray[1]);
395   EXPECT_EQ(std::vector<uint8_t>({0, 0x32, 0x31, 0, 0, 0, 0, 0, 0, 0}),
396             DataBytes);
397 
398   Reader.setOffset(0);
399   Writer.setOffset(0);
400   ::memset(DataBytes.data(), 0, 10);
401   EXPECT_THAT_ERROR(Writer.writeArray(intArray[0]), Succeeded());
402   EXPECT_THAT_ERROR(Reader.readArray(intArray[1], intArray[0].size()),
403                     Succeeded());
404   EXPECT_EQ(intArray[0], intArray[1]);
405 }
406 
407 TEST(MappedBlockStreamTest, TestWriteContiguousStreamRef) {
408   std::vector<uint8_t> DestDataBytes(10);
409   MutableArrayRef<uint8_t> DestData(DestDataBytes);
410   const uint32_t DestBlocks[] = {2, 1, 0, 6, 3, 4, 5, 7, 9, 8};
411 
412   std::vector<uint8_t> SrcDataBytes(10);
413   MutableArrayRef<uint8_t> SrcData(SrcDataBytes);
414 
415   DiscontiguousStream F(DestBlocks, DestData);
416   auto DestStream = WritableMappedBlockStream::createStream(
417       F.block_size(), F.layout(), F, F.Allocator);
418 
419   // First write "Test Str" into the source stream.
420   MutableBinaryByteStream SourceStream(SrcData, little);
421   BinaryStreamWriter SourceWriter(SourceStream);
422   EXPECT_THAT_ERROR(SourceWriter.writeCString("Test Str"), Succeeded());
423   EXPECT_EQ(SrcDataBytes, std::vector<uint8_t>(
424                               {'T', 'e', 's', 't', ' ', 'S', 't', 'r', 0, 0}));
425 
426   // Then write the source stream into the dest stream.
427   BinaryStreamWriter DestWriter(*DestStream);
428   EXPECT_THAT_ERROR(DestWriter.writeStreamRef(SourceStream), Succeeded());
429   EXPECT_EQ(DestDataBytes, std::vector<uint8_t>(
430                                {'s', 'e', 'T', ' ', 'S', 't', 't', 'r', 0, 0}));
431 
432   // Then read the string back out of the dest stream.
433   StringRef Result;
434   BinaryStreamReader DestReader(*DestStream);
435   EXPECT_THAT_ERROR(DestReader.readCString(Result), Succeeded());
436   EXPECT_EQ(Result, "Test Str");
437 }
438 
439 TEST(MappedBlockStreamTest, TestWriteDiscontiguousStreamRef) {
440   std::vector<uint8_t> DestDataBytes(10);
441   MutableArrayRef<uint8_t> DestData(DestDataBytes);
442   const uint32_t DestBlocks[] = {2, 1, 0, 6, 3, 4, 5, 7, 9, 8};
443 
444   std::vector<uint8_t> SrcDataBytes(10);
445   MutableArrayRef<uint8_t> SrcData(SrcDataBytes);
446   const uint32_t SrcBlocks[] = {1, 0, 6, 3, 4, 5, 2, 7, 8, 9};
447 
448   DiscontiguousStream DestF(DestBlocks, DestData);
449   DiscontiguousStream SrcF(SrcBlocks, SrcData);
450 
451   auto Dest = WritableMappedBlockStream::createStream(
452       DestF.block_size(), DestF.layout(), DestF, DestF.Allocator);
453   auto Src = WritableMappedBlockStream::createStream(
454       SrcF.block_size(), SrcF.layout(), SrcF, SrcF.Allocator);
455 
456   // First write "Test Str" into the source stream.
457   BinaryStreamWriter SourceWriter(*Src);
458   EXPECT_THAT_ERROR(SourceWriter.writeCString("Test Str"), Succeeded());
459   EXPECT_EQ(SrcDataBytes, std::vector<uint8_t>(
460                               {'e', 'T', 't', 't', ' ', 'S', 's', 'r', 0, 0}));
461 
462   // Then write the source stream into the dest stream.
463   BinaryStreamWriter DestWriter(*Dest);
464   EXPECT_THAT_ERROR(DestWriter.writeStreamRef(*Src), Succeeded());
465   EXPECT_EQ(DestDataBytes, std::vector<uint8_t>(
466                                {'s', 'e', 'T', ' ', 'S', 't', 't', 'r', 0, 0}));
467 
468   // Then read the string back out of the dest stream.
469   StringRef Result;
470   BinaryStreamReader DestReader(*Dest);
471   EXPECT_THAT_ERROR(DestReader.readCString(Result), Succeeded());
472   EXPECT_EQ(Result, "Test Str");
473 }
474 
475 TEST(MappedBlockStreamTest, DataLivesAfterStreamDestruction) {
476   std::vector<uint8_t> DataBytes(10);
477   MutableArrayRef<uint8_t> Data(DataBytes);
478   const uint32_t Blocks[] = {2, 1, 0, 6, 3, 4, 5, 7, 9, 8};
479 
480   StringRef Str[] = {"Zero Str", ""};
481 
482   DiscontiguousStream F(Blocks, Data);
483   {
484     auto S = WritableMappedBlockStream::createStream(F.block_size(), F.layout(),
485                                                      F, F.Allocator);
486 
487     BinaryStreamReader Reader(*S);
488     BinaryStreamWriter Writer(*S);
489     ::memset(DataBytes.data(), 0, 10);
490     EXPECT_THAT_ERROR(Writer.writeCString(Str[0]), Succeeded());
491     EXPECT_THAT_ERROR(Reader.readCString(Str[1]), Succeeded());
492     EXPECT_EQ(Str[0], Str[1]);
493   }
494 
495   EXPECT_EQ(Str[0], Str[1]);
496 }
497 
498 } // end anonymous namespace
499