maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[clangd] make zlib compression optional for binary format 

llvm-svn: 341465
This commit is contained in:
Sam McCall 2018-09-05 13:17:47 +00:00
parent 591d889006
commit e4fa7b8418
1 changed files with 29 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
clang-tools-extra/clangd/index/Serialization.cpp
View File

@ -86,7 +86,7 @@ uint32_t consumeVar(StringRef &Data) {
// We store each string once, and refer to them by index.
//
// The string table's format is:
// - UncompressedSize : uint32
// - UncompressedSize : uint32 (or 0 for no compression)
// - CompressedData : byte[CompressedSize]
//
// CompressedData is a zlib-compressed byte[UncompressedSize].
@ -102,6 +102,11 @@ class StringTableOut {
DenseMap<std::pair<const char *, size_t>, unsigned> Index;
public:
StringTableOut() {
// Ensure there's at least one string in the table.
// Table size zero is reserved to indicate no compression.
Unique.insert("");
}
// Add a string to the table. Overwrites S if an identical string exists.
void intern(StringRef &S) { S = *Unique.insert(S).first; };
// Finalize the table and write it to OS. No more strings may be added.
@ -116,10 +121,15 @@ public:
RawTable.append(S);
RawTable.push_back(0);
}
SmallString<1> Compressed;
cantFail(zlib::compress(RawTable, Compressed));
write32(RawTable.size(), OS);
OS << Compressed;
if (zlib::isAvailable()) {
SmallString<1> Compressed;
cantFail(zlib::compress(RawTable, Compressed));
write32(RawTable.size(), OS);
OS << Compressed;
} else {
write32(0, OS); // No compression.
OS << RawTable;
}
}
// Get the ID of an string, which must be interned. Table must be finalized.
unsigned index(StringRef S) const {
@ -138,9 +148,17 @@ Expected<StringTableIn> readStringTable(StringRef Data) {
if (Data.size() < 4)
return makeError("Bad string table: not enough metadata");
size_t UncompressedSize = consume32(Data);
SmallString<1> Uncompressed;
if (Error E = llvm::zlib::uncompress(Data, Uncompressed, UncompressedSize))
return std::move(E);
StringRef Uncompressed;
SmallString<1> UncompressedStorage;
if (UncompressedSize == 0) // No compression
Uncompressed = Data;
else {
if (Error E =
llvm::zlib::uncompress(Data, UncompressedStorage, UncompressedSize))
return std::move(E);
Uncompressed = UncompressedStorage;
}
StringTableIn Table;
StringSaver Saver(Table.Arena);
@ -285,9 +303,9 @@ Expected<Symbol> readSymbol(StringRef &Data, const StringTableIn &Strings) {
// - symb: symbols
// The current versioning scheme is simple - non-current versions are rejected.
// This allows arbitrary format changes, which invalidate stored data.
// Later we may want to support some backward compatibility.
constexpr static uint32_t Version = 1;
// If you make a breaking change, bump this version number to invalidate stored
// data. Later we may want to support some backward compatibility.
constexpr static uint32_t Version = 2;
Expected<IndexFileIn> readIndexFile(StringRef Data) {
auto RIFF = riff::readFile(Data);