Changes the JSON parser to use the SourceMgr.

Diagnostics are now emitted via the SourceMgr and we use MemoryBuffer
for buffer management. Switched the code to make use of the trailing
'0' that MemoryBuffer guarantees where it makes sense.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147063 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 33 insertions, 26 deletions

diff --git a/lib/Support/JSONParser.cpp b/lib/Support/JSONParser.cpp
index 994ca9f..205ac05 100644
--- a/lib/Support/JSONParser.cpp
+++ b/lib/Support/JSONParser.cpp
@@ -15,14 +15,20 @@
 
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/Casting.h"
+#include "llvm/Support/MemoryBuffer.h"
 
 using namespace llvm;
 
-JSONParser::JSONParser(StringRef Input)
-  : Input(Input), Position(Input.begin()) {}
+JSONParser::JSONParser(StringRef Input, SourceMgr *SM)
+  : SM(SM), Failed(false) {
+  InputBuffer = MemoryBuffer::getMemBuffer(Input, "JSON");
+  SM->AddNewSourceBuffer(InputBuffer, SMLoc());
+  End = InputBuffer->getBuffer().end();
+  Position = InputBuffer->getBuffer().begin();
+}
 
 JSONValue *JSONParser::parseRoot() {
-  if (Position != Input.begin())
+  if (Position != InputBuffer->getBuffer().begin())
     report_fatal_error("Cannot resuse JSONParser.");
   if (isWhitespace())
     nextNonWhitespace();
@@ -40,7 +46,11 @@ JSONValue *JSONParser::parseRoot() {
 }
 
 bool JSONParser::validate() {
-  return skip(*parseRoot());
+  JSONValue *Root = parseRoot();
+  if (Root == NULL) {
+    return false;
+  }
+  return skip(*Root);
 }
 
 bool JSONParser::skip(const JSONAtom &Atom) {
@@ -55,22 +65,23 @@ bool JSONParser::skip(const JSONAtom &Atom) {
 }
 
 // Sets the current error to:
-// "Error while parsing JSON: expected <Expected>, but found <Found>".
+// "expected <Expected>, but found <Found>".
 void JSONParser::setExpectedError(StringRef Expected, StringRef Found) {
-  ErrorMessage = ("Error while parsing JSON: expected " +
-    Expected + ", but found " + Found + ".").str();
+  SM->PrintMessage(SMLoc::getFromPointer(Position), SourceMgr::DK_Error,
+    "expected " + Expected + ", but found " + Found + ".", ArrayRef<SMRange>());
+  Failed = true;
 }
 
 // Sets the current error to:
-// "Error while parsing JSON: expected <Expected>, but found <Found>".
+// "expected <Expected>, but found <Found>".
 void JSONParser::setExpectedError(StringRef Expected, char Found) {
-  setExpectedError(Expected, StringRef(&Found, 1));
+  setExpectedError(Expected, ("'" + StringRef(&Found, 1) + "'").str());
 }
 
 // If there is no character available, returns true and sets the current error
-// to: "Error while parsing JSON: expected <Expected>, but found EOF.".
+// to: "expected <Expected>, but found EOF.".
 bool JSONParser::errorIfAtEndOfFile(StringRef Expected) {
-  if (Position == Input.end()) {
+  if (Position == End) {
     setExpectedError(Expected, "EOF");
     return true;
   }
@@ -78,12 +89,12 @@ bool JSONParser::errorIfAtEndOfFile(StringRef Expected) {
 }
 
 // Sets the current error if the current character is not C to:
-// "Error while parsing JSON: expected 'C', but got <current character>".
+// "expected 'C', but got <current character>".
 bool JSONParser::errorIfNotAt(char C, StringRef Message) {
-  if (Position == Input.end() || *Position != C) {
+  if (*Position != C) {
     std::string Expected =
       ("'" + StringRef(&C, 1) + "' " + Message).str();
-    if (Position == Input.end())
+    if (Position == End)
       setExpectedError(Expected, "EOF");
     else
       setExpectedError(Expected, *Position);
@@ -113,7 +124,7 @@ static bool wasEscaped(StringRef::iterator First,
 
 // Parses a JSONString, assuming that the current position is on a quote.
 JSONString *JSONParser::parseString() {
-  assert(Position != Input.end());
+  assert(Position != End);
   assert(!isWhitespace());
   if (errorIfNotAt('"', "at start of string"))
     return 0;
@@ -136,9 +147,9 @@ JSONString *JSONParser::parseString() {
     // Step over the current quote.
     ++Position;
     // Find the next quote.
-    while (Position != Input.end() && *Position != '"')
+    while (Position != End && *Position != '"')
       ++Position;
-    if (errorIfAtEndOfFile("\" at end of string"))
+    if (errorIfAtEndOfFile("'\"' at end of string"))
       return 0;
     // Repeat until the previous character was not a '\' or was an escaped
     // backslash.
@@ -158,22 +169,18 @@ void JSONParser::nextNonWhitespace() {
 
 // Checks if there is a whitespace character at the current position.
 bool JSONParser::isWhitespace() {
-  return Position != Input.end() && (*Position == ' ' || *Position == '\t' ||
-                                     *Position == '\n' || *Position == '\r');
+  return *Position == ' ' || *Position == '\t' ||
+         *Position == '\n' || *Position == '\r';
 }
 
 bool JSONParser::failed() const {
-  return !ErrorMessage.empty();
-}
-
-std::string JSONParser::getErrorMessage() const {
-  return ErrorMessage;
+  return Failed;
 }
 
 // Parses a JSONValue, assuming that the current position is at the first
 // character of the value.
 JSONValue *JSONParser::parseValue() {
-  assert(Position != Input.end());
+  assert(Position != End);
   assert(!isWhitespace());
   switch (*Position) {
     case '[':
@@ -191,7 +198,7 @@ JSONValue *JSONParser::parseValue() {
 // Parses a JSONKeyValuePair, assuming that the current position is at the first
 // character of the key, value pair.
 JSONKeyValuePair *JSONParser::parseKeyValuePair() {
-  assert(Position != Input.end());
+  assert(Position != End);
   assert(!isWhitespace());
 
   JSONString *Key = parseString();