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authorTom Sepez <tsepez@chromium.org>2017-03-30 15:28:23 -0700
committerChromium commit bot <commit-bot@chromium.org>2017-03-30 23:00:56 +0000
commit3efc06752c56b731e11d37310b981254c1ba461c (patch)
treeb497a162a0f60ea3101d84d678662ab6ff8bf672 /core
parentbf9104d5825d9f62b59106d69edebb1b5bdd48da (diff)
downloadpdfium-3efc06752c56b731e11d37310b981254c1ba461c.tar.xz
vswprintf() part 2: retry when clearly out of space.chromium/3057
Use vendor guidance if possible. Otherwise, avoid allocating N^2 storage for N wide chars. Update tests to account for strings removed from helper. Change-Id: I38bbaf936656fb43ec1ae33652da4cabde00247a Reviewed-on: https://pdfium-review.googlesource.com/3433 Commit-Queue: Tom Sepez <tsepez@chromium.org> Reviewed-by: Lei Zhang <thestig@chromium.org>
Diffstat (limited to 'core')
-rw-r--r--core/fxcrt/fx_basic_wstring.cpp60
-rw-r--r--core/fxcrt/fx_basic_wstring_unittest.cpp4
-rw-r--r--core/fxcrt/fx_string.h3
3 files changed, 39 insertions, 28 deletions
diff --git a/core/fxcrt/fx_basic_wstring.cpp b/core/fxcrt/fx_basic_wstring.cpp
index 0c245dc61a..99002e581f 100644
--- a/core/fxcrt/fx_basic_wstring.cpp
+++ b/core/fxcrt/fx_basic_wstring.cpp
@@ -66,11 +66,11 @@ const wchar_t* FX_wcsstr(const wchar_t* haystack,
return nullptr;
}
-FX_STRSIZE GuessSizeForVSWPrintf(const wchar_t*& pFormat, va_list argList) {
+FX_STRSIZE GuessSizeForVSWPrintf(const wchar_t* pFormat, va_list argList) {
FX_STRSIZE nMaxLen = 0;
for (const wchar_t* pStr = pFormat; *pStr != 0; pStr++) {
if (*pStr != '%' || *(pStr = pStr + 1) == '%') {
- nMaxLen += FXSYS_wcslen(pStr);
+ ++nMaxLen;
continue;
}
int nItemLen = 0;
@@ -89,11 +89,8 @@ FX_STRSIZE GuessSizeForVSWPrintf(const wchar_t*& pFormat, va_list argList) {
while (std::iswdigit(*pStr))
++pStr;
}
- if (nWidth < 0 || nWidth > 128 * 1024) {
- pFormat = L"Bad width";
- nMaxLen = 10;
- break;
- }
+ if (nWidth < 0 || nWidth > 128 * 1024)
+ return -1;
int nPrecision = 0;
if (*pStr == '.') {
pStr++;
@@ -106,11 +103,8 @@ FX_STRSIZE GuessSizeForVSWPrintf(const wchar_t*& pFormat, va_list argList) {
++pStr;
}
}
- if (nPrecision < 0 || nPrecision > 128 * 1024) {
- pFormat = L"Bad precision";
- nMaxLen = 14;
- break;
- }
+ if (nPrecision < 0 || nPrecision > 128 * 1024)
+ return -1;
int nModifier = 0;
if (*pStr == L'I' && *(pStr + 1) == L'6' && *(pStr + 2) == L'4') {
pStr += 3;
@@ -258,6 +252,7 @@ FX_STRSIZE GuessSizeForVSWPrintf(const wchar_t*& pFormat, va_list argList) {
}
nMaxLen += nItemLen;
}
+ nMaxLen += 32; // Fudge factor.
return nMaxLen;
}
@@ -599,30 +594,43 @@ void CFX_WideString::AllocCopy(CFX_WideString& dest,
dest.m_pData.Swap(pNewData);
}
-void CFX_WideString::FormatV(const wchar_t* pFormat, va_list argList) {
- va_list argListCopy;
- FX_VA_COPY(argListCopy, argList);
- FX_STRSIZE nMaxLen = GuessSizeForVSWPrintf(pFormat, argListCopy);
- va_end(argListCopy);
- if (nMaxLen <= 0)
- return;
-
- GetBuffer(nMaxLen);
+bool CFX_WideString::TryVSWPrintf(FX_STRSIZE size,
+ const wchar_t* pFormat,
+ va_list argList) {
+ GetBuffer(size);
if (!m_pData)
- return;
+ return true;
- FX_VA_COPY(argListCopy, argList);
// In the following two calls, there's always space in the buffer for
// a terminating NUL that's not included in nMaxLen.
// For vswprintf(), MSAN won't untaint the buffer on a truncated write's
// -1 return code even though the buffer is written. Probably just as well
// not to trust the vendor's implementation to write anything anyways.
// See https://crbug.com/705912.
- memset(m_pData->m_String, 0, (nMaxLen + 1) * sizeof(wchar_t));
- FXSYS_vswprintf((wchar_t*)m_pData->m_String, nMaxLen + 1,
- (const wchar_t*)pFormat, argListCopy);
+ memset(m_pData->m_String, 0, (size + 1) * sizeof(wchar_t));
+ int ret = vswprintf(m_pData->m_String, size + 1, pFormat, argList);
ReleaseBuffer();
+ return ret >= 0 || m_pData->m_String[size - 1] == 0;
+}
+
+void CFX_WideString::FormatV(const wchar_t* pFormat, va_list argList) {
+ va_list argListCopy;
+ FX_VA_COPY(argListCopy, argList);
+ FX_STRSIZE nMaxLen = vswprintf(nullptr, 0, pFormat, argListCopy);
va_end(argListCopy);
+ if (nMaxLen <= 0) {
+ nMaxLen = GuessSizeForVSWPrintf(pFormat, argListCopy);
+ if (nMaxLen <= 0)
+ return;
+ }
+ while (nMaxLen < 32 * 1024) {
+ FX_VA_COPY(argListCopy, argList);
+ bool bRetryPointless = TryVSWPrintf(nMaxLen, pFormat, argListCopy);
+ va_end(argListCopy);
+ if (bRetryPointless)
+ break;
+ nMaxLen *= 2;
+ }
}
void CFX_WideString::Format(const wchar_t* pFormat, ...) {
diff --git a/core/fxcrt/fx_basic_wstring_unittest.cpp b/core/fxcrt/fx_basic_wstring_unittest.cpp
index ceb4616b8a..c5151709e0 100644
--- a/core/fxcrt/fx_basic_wstring_unittest.cpp
+++ b/core/fxcrt/fx_basic_wstring_unittest.cpp
@@ -890,7 +890,7 @@ TEST(fxcrt, WideStringFormatWidth) {
{
CFX_WideString str;
str.Format(L"%1048576d", 1);
- EXPECT_EQ(L"Bad width", str);
+ EXPECT_EQ(L"", str);
}
}
@@ -928,7 +928,7 @@ TEST(fxcrt, WideStringFormatPrecision) {
{
CFX_WideString str;
str.Format(L"%.1048576f", 1.2);
- EXPECT_EQ(L"Bad precision", str);
+ EXPECT_EQ(L"", str);
}
}
diff --git a/core/fxcrt/fx_string.h b/core/fxcrt/fx_string.h
index 494633e41d..f276853197 100644
--- a/core/fxcrt/fx_string.h
+++ b/core/fxcrt/fx_string.h
@@ -357,6 +357,9 @@ class CFX_WideString {
void AssignCopy(const wchar_t* pSrcData, FX_STRSIZE nSrcLen);
void Concat(const wchar_t* lpszSrcData, FX_STRSIZE nSrcLen);
+ // Returns true unless we ran out of space.
+ bool TryVSWPrintf(FX_STRSIZE size, const wchar_t* format, va_list argList);
+
CFX_RetainPtr<StringData> m_pData;
friend class fxcrt_WideStringConcatInPlace_Test;