зеркало из https://github.com/mozilla/gecko-dev.git
relanding patch for bug 132517 "prefs.js frequently truncated on exit or crash" r=ccarlen sr=bryner a=chofmann
This commit is contained in:
darin%meer.net
Родитель
f6847771d4
Коммит
033fd13e16
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@ -475,6 +475,7 @@ nsresult nsPrefService::WritePrefFile(nsIFile* aFile)
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NS_LINEBREAK
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NS_LINEBREAK;
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nsCOMPtr<nsIOutputStream> outStreamSink;
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nsCOMPtr<nsIOutputStream> outStream;
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PRUint32 writeAmount;
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nsresult rv;
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@ -491,25 +492,35 @@ nsresult nsPrefService::WritePrefFile(nsIFile* aFile)
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#endif
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// execute a "safe" save by saving through a tempfile
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PRInt32 numCopies = 1;
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mRootBranch->GetIntPref("backups.number_of_prefs_copies", &numCopies);
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nsSafeSaveFile safeSave(aFile, numCopies);
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rv = safeSave.CreateBackup(nsSafeSaveFile::kPurgeNone);
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nsSafeSaveFile safeSave;
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nsCOMPtr<nsIFile> tempFile;
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rv = safeSave.Init(aFile, getter_AddRefs(tempFile));
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if (NS_FAILED(rv))
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return rv;
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// this clone of tempFile exists to defeat the stat caching "feature" of
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// nsLocalFile. when tempFileClone is opened, nsLocalFile will stat the
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// file and cache the results. it will return those cached results when
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// we later ask tempFile for its size. as a result we will think that
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// we didn't write anything to the file, and our logic here will fail
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// miserably. nsLocalFile should probably be fixed to not cache stat
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// results when returning a writable file descriptor. see bug 132517.
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nsCOMPtr<nsIFile> tempFileClone;
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rv = tempFile->Clone(getter_AddRefs(tempFileClone));
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if (NS_FAILED(rv))
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return rv;
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rv = NS_NewLocalFileOutputStream(getter_AddRefs(outStreamSink), tempFileClone);
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if (NS_FAILED(rv))
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return rv;
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rv = NS_NewBufferedOutputStream(getter_AddRefs(outStream), outStreamSink, 4096);
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if (NS_FAILED(rv))
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return rv;
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char** valueArray = (char **)PR_Calloc(sizeof(char *), gHashTable.entryCount);
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if (!valueArray)
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return NS_ERROR_OUT_OF_MEMORY;
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rv = NS_NewLocalFileOutputStream(getter_AddRefs(outStream), aFile);
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if (NS_FAILED(rv))
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return rv;
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// write out the file header
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rv = outStream->Write(outHeader, sizeof(outHeader) - 1, &writeAmount);
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pref_saveArgs saveArgs;
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saveArgs.prefArray = valueArray;
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saveArgs.saveTypes = SAVE_ALL;
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@ -528,6 +539,10 @@ nsresult nsPrefService::WritePrefFile(nsIFile* aFile)
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/* Sort the preferences to make a readable file on disk */
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NS_QuickSort(valueArray, gHashTable.entryCount, sizeof(char *), pref_CompareStrings, NULL);
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// write out the file header
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rv = outStream->Write(outHeader, sizeof(outHeader) - 1, &writeAmount);
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char** walker = valueArray;
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for (PRUint32 valueIdx = 0; valueIdx < gHashTable.entryCount; valueIdx++, walker++) {
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if (*walker) {
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@ -544,15 +559,19 @@ nsresult nsPrefService::WritePrefFile(nsIFile* aFile)
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PR_Free(valueArray);
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outStream->Close();
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// if save failed replace the original file from backup
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if (NS_FAILED(rv)) {
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nsresult rv2;
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rv2 = safeSave.RestoreFromBackup();
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if (NS_SUCCEEDED(rv2)) {
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// we failed to write the file, but managed to restore the previous one...
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rv = NS_OK;
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}
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}
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PRInt64 tempLL;
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PRUint32 oldFileSize, newFileSize;
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(void)aFile->GetFileSize(&tempLL); // All impls return 0 for size on failure.
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LL_L2UI(oldFileSize, tempLL);
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(void)tempFile->GetFileSize(&tempLL);
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LL_L2UI(newFileSize, tempLL);
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// As long as we have succeeded, move the temp file to the actual file.
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// But, if the new file is only 1/2 the size of the old file (dataloss),
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// pass TRUE for aBackupTarget, leaving the old file on disk.
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safeSave.OnSaveFinished(NS_SUCCEEDED(rv),
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oldFileSize && ((newFileSize << 1) <= oldFileSize));
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if (NS_SUCCEEDED(rv))
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gDirty = PR_FALSE;
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return rv;
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@ -38,207 +38,92 @@
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#include "nsSafeSaveFile.h"
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nsSafeSaveFile::nsSafeSaveFile(nsIFile *aTargetFile, PRInt32 aNumBackupCopies)
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: mBackupNameLen(0),
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mBackupCount(aNumBackupCopies)
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nsresult nsSafeSaveFile::Init(nsIFile *aTargetFile, nsIFile **aTempFile)
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{
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nsCAutoString targetFileName;
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const char * temp;
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nsresult rv;
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// determine if the target file currently exists
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// if the target file doesn't exist this object does nothing
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if (NS_FAILED(aTargetFile->Exists(&mTargetFileExists)))
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mTargetFileExists = PR_FALSE;
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if (!mTargetFileExists)
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return;
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// determine the actual filename (less the extension)
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rv = aTargetFile->GetNativeLeafName(targetFileName);
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if (NS_FAILED(rv)) // yikes! out of memory
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return;
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// keep a reference to the file that will be saved
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NS_ASSERTION(aTargetFile, "null pointer");
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NS_ASSERTION(aTempFile, "null pointer");
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*aTempFile = nsnull;
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nsresult rv;
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rv = aTargetFile->Exists(&mTargetFileExists);
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if (NS_FAILED(rv)) {
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NS_ERROR("Can't tell if target file exists");
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mTargetFileExists = PR_TRUE; // Safer to assume it exists - we just do more work.
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}
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nsCOMPtr<nsIFile> tempResult;
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rv = aTargetFile->Clone(getter_AddRefs(tempResult));
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if (NS_SUCCEEDED(rv) && mTargetFileExists) {
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PRUint32 perm;
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if (NS_FAILED(aTargetFile->GetPermissions(&perm))) {
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NS_ERROR("Can't get permissions of target file");
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perm = 0700;
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}
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rv = tempResult->CreateUnique(nsIFile::NORMAL_FILE_TYPE, perm);
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}
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if (NS_SUCCEEDED(rv)) {
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NS_ADDREF(*aTempFile = tempResult);
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mTargetFile = aTargetFile;
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// determine the file name (less the extension)
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temp = strrchr(targetFileName.get(), '.');
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if (temp)
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mBackupNameLen = temp - targetFileName.get();
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else
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mBackupNameLen = targetFileName.Length();
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// save the name of the backup file and its length
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mBackupFileName = Substring(targetFileName, 0, mBackupNameLen) + NS_LITERAL_CSTRING(".bak");
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mBackupNameLen = mBackupFileName.Length();
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// create a new file object that points to our backup file... this isn't
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// absolutely necessary, but it does allow us to easily transistion to a
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// model where all .bak are stored in a single directory if so desired.
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rv = aTargetFile->Clone(getter_AddRefs(mBackupFile));
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if (NS_SUCCEEDED(rv))
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mBackupFile->SetNativeLeafName(mBackupFileName);
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mTempFile = tempResult;
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}
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return rv;
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}
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nsSafeSaveFile::~nsSafeSaveFile(void)
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nsresult nsSafeSaveFile::OnSaveFinished(PRBool aSaveSucceeded, PRBool aBackupTarget)
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{
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// if the target file didn't exist nothing was backed up
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if (mTargetFileExists && mBackupFile) {
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// if no backups desired, remove the backup file
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if (mBackupCount == 0) {
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mBackupFile->Remove(PR_FALSE);
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}
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}
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}
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nsresult rv = NS_OK;
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if (aSaveSucceeded) {
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NS_ENSURE_STATE(mTargetFile && mTempFile);
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nsresult nsSafeSaveFile::CreateBackup(PurgeBackupType aPurgeType)
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{
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nsCOMPtr<nsIFile> backupParent;
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nsresult rv, rv2;
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PRBool bExists;
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// if the target file doesn't exist there is nothing to backup
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if (!mTargetFileExists)
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return NS_OK;
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// if a backup file currently exists... do the right thing
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if (mBackupFile && NS_SUCCEEDED(mBackupFile->Exists(&bExists)) && bExists) {
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rv = ManageRedundantBackups();
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if (NS_FAILED(rv))
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return rv;
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if (!mTargetFileExists) {
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// If the target file did not exist when we were initialized, then the
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// temp file we gave out was actually a reference to the target file.
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// since we succeeded in writing to the temp file (and hence succeeded
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// in writing to the target file), there is nothing more to do.
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#ifdef DEBUG
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PRBool equal;
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if (NS_FAILED(mTargetFile->Equals(mTempFile, &equal)) || !equal)
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NS_ERROR("mTempFile not equal to mTargetFile");
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#endif
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return NS_OK;
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}
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// and finally, copy the file (preserves file permissions)
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rv2 = NS_OK;
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do {
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rv = mTargetFile->CopyToNative(nsnull, mBackupFileName);
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if (NS_SUCCEEDED(rv))
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break;
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switch (rv) {
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case NS_ERROR_FILE_DISK_FULL: // Mac
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case NS_ERROR_FILE_TOO_BIG: // Windows
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case NS_ERROR_FILE_NO_DEVICE_SPACE: // Who knows...
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if (aPurgeType == kPurgeNone) {
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return rv;
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} if (aPurgeType == kPurgeOne) {
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aPurgeType = kPurgeNone;
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}
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rv2 = PurgeOldestRedundantBackup();
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break;
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default:
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return rv;
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break;
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}
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} while (rv2 == NS_OK);
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return rv;
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}
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nsresult nsSafeSaveFile::RestoreFromBackup(void)
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{
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nsCOMPtr<nsIFile> parentDir;
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nsCAutoString fileName;
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nsresult rv;
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// if the target file didn't initially exist there is nothing to restore from
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if (!mTargetFileExists)
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return NS_ERROR_FILE_NOT_FOUND;
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if (!mBackupFile)
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return NS_ERROR_NOT_INITIALIZED;
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rv = mTargetFile->GetNativeLeafName(fileName);
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if (NS_FAILED(rv)) // yikes! out of memory
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return rv;
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// Ugh, copy only takes a directory and a name, lets "unpackage" our target file...
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rv = mTargetFile->GetParent(getter_AddRefs(parentDir));
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if (NS_FAILED(rv))
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return rv;
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// kill the target... it's bad anyway
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mTargetFile->Remove(PR_FALSE);
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// and finally, copy the file (preserves file permissions)
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rv = mBackupFile->CopyToNative(parentDir, fileName);
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return rv;
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}
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nsresult nsSafeSaveFile::ManageRedundantBackups(void)
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{
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nsCOMPtr<nsIFile> backupFile;
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nsCAutoString fileName;
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nsresult rv;
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PRBool bExists;
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rv = mBackupFile->Clone(getter_AddRefs(backupFile));
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if (NS_FAILED(rv)) // yikes! out of memory, probably best to not continue
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return rv;
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if (mBackupCount > 0) {
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// kill the (oldest) backup copy, if necessary
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fileName = mBackupFileName;
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if (mBackupCount > 1)
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fileName.AppendInt(mBackupCount - 1);
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backupFile->SetNativeLeafName(fileName);
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}
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// remove the file as determined by the logic above
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backupFile->Remove(PR_FALSE);
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// bump any redundant backups up one (i.e. bak -> bak1, bak1 -> bak2, etc.)
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if (mBackupCount > 1) {
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PRInt32 backupCount = mBackupCount;
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fileName = mBackupFileName;
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while (--backupCount > 0) {
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if (backupCount > 1)
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fileName.AppendInt(backupCount - 1);
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backupFile->SetNativeLeafName(fileName);
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backupFile->Exists(&bExists);
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if (bExists) {
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fileName.Truncate(mBackupNameLen);
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fileName.AppendInt(backupCount);
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// fail silently because it's not important enough to bail on the save for
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backupFile->MoveToNative(0, fileName);
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}
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fileName.Truncate(mBackupNameLen);
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};
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}
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return NS_OK;
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}
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nsresult nsSafeSaveFile::PurgeOldestRedundantBackup(void)
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{
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nsCOMPtr<nsIFile> backupFile;
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nsCAutoString fileName;
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nsresult rv;
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if (!mBackupFile)
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return NS_ERROR_NULL_POINTER;
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rv = mBackupFile->Clone(getter_AddRefs(backupFile));
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if (NS_FAILED(rv)) // yikes! out of memory, probably best to not continue
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return rv;
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// if no redundant backups, nothing to delete
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if (mBackupCount <= 1)
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return NS_ERROR_FILE_NOT_FOUND;
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PRInt32 backupCount = mBackupCount;
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fileName = mBackupFileName;
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while (--backupCount > 0) {
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fileName.AppendInt(backupCount);
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backupFile->SetNativeLeafName(fileName);
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rv = backupFile->Remove(PR_FALSE);
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nsCAutoString targetFilename;
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rv = mTargetFile->GetNativeLeafName(targetFilename);
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if (aBackupTarget) {
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// Create a copy of the target before we overwrite it
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nsCAutoString backupFilename(targetFilename);
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PRInt32 pos = backupFilename.RFindChar('.');
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if (pos != -1)
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backupFilename.Truncate(pos);
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backupFilename.Append(NS_LITERAL_CSTRING(".bak"));
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// Find a unique name for the backup by using CreateUnique
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nsCOMPtr<nsIFile> uniqueFile;
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rv = mTargetFile->Clone(getter_AddRefs(uniqueFile));
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if (NS_SUCCEEDED(rv)) {
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rv = uniqueFile->SetNativeLeafName(backupFilename);
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if (NS_SUCCEEDED(rv)) {
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return NS_OK;
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rv = uniqueFile->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0600);
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if (NS_SUCCEEDED(rv)) {
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uniqueFile->GetNativeLeafName(backupFilename);
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uniqueFile->Remove(PR_FALSE);
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// Finally, move the target to the backup
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mTargetFile->MoveToNative(nsnull, backupFilename);
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}
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}
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fileName.Truncate(mBackupNameLen);
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};
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return NS_ERROR_FILE_NOT_FOUND;
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}
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}
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if (NS_SUCCEEDED(rv))
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rv = mTempFile->MoveToNative(nsnull, targetFilename); // This will replace target
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}
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else {
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NS_ENSURE_STATE(mTempFile);
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rv = mTempFile->Remove(PR_FALSE);
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}
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return rv;
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}
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@ -41,27 +41,15 @@
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class nsSafeSaveFile {
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public:
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enum PurgeBackupType {
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kPurgeNone = 0, kPurgeOne = 1, kPurgeAll = 2
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};
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nsSafeSaveFile() {}
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~nsSafeSaveFile() {}
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nsSafeSaveFile(nsIFile *aTargetFile, PRInt32 aNumBackupCopies = 0);
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virtual ~nsSafeSaveFile(void);
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nsresult CreateBackup(PurgeBackupType aPurgeType);
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nsresult RestoreFromBackup(void);
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protected:
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nsSafeSaveFile(void) {};
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nsresult ManageRedundantBackups(void);
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nsresult PurgeOldestRedundantBackup(void);
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nsresult Init(nsIFile *aTargetFile, nsIFile **aTempFile);
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nsresult OnSaveFinished(PRBool aSaveSucceeded, PRBool aBackupTarget);
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private:
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nsCOMPtr<nsIFile> mTargetFile;
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PRBool mTargetFileExists;
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nsCOMPtr<nsIFile> mBackupFile;
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nsCString mBackupFileName; // native charset
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PRInt32 mBackupNameLen;
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PRInt32 mBackupCount;
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nsCOMPtr<nsIFile> mTempFile;
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};
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