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Handle return values from fread() and fwrite() in PLATFORM_copyFile()

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Whenever I compile with -O2, GCC gives me a warning that the return
value of fread() is being ignored. Which is a fair point, it means that
we're not doing proper error handling if something goes wrong. But I'm
also going to check the return value of fwrite() for good measure.

I believe that checking that this number is not equal to length is the
way to catch all errors and output an error message accordingly. I
didn't use ferror() or feof() mostly because I think it takes up too
much code. Also an error from fwrite() only says "Warning" because I
don't think there's much we can do if we don't fully write all bytes to
the intended file.
This commit is contained in:
Misa 2020-05-18 14:03:14 -07:00 committed by Ethan Lee
parent 664bf8ca6c
commit bf21c13f80
1 changed files with 13 additions and 3 deletions
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16
desktop_version/src/FileSystemUtils.cpp
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@ -438,7 +438,7 @@ void PLATFORM_migrateSaveData(char* output)
void PLATFORM_copyFile(const char *oldLocation, const char *newLocation)
{
char *data;
long int length;
size_t length, bytes_read, bytes_written;
/* Read data */
FILE *file = fopen(oldLocation, "rb");
@ -451,8 +451,14 @@ void PLATFORM_copyFile(const char *oldLocation, const char *newLocation)
length = ftell(file);
fseek(file, 0, SEEK_SET);
data = (char*) malloc(length);
fread(data, 1, length, file);
bytes_read = fread(data, 1, length, file);
fclose(file);
if (bytes_read != length)
{
printf("An error occurred when reading from %s\n", oldLocation);
free(data);
return;
}
/* Write data */
file = fopen(newLocation, "wb");
@ -462,12 +468,16 @@ void PLATFORM_copyFile(const char *oldLocation, const char *newLocation)
free(data);
return;
}
fwrite(data, 1, length, file);
bytes_written = fwrite(data, 1, length, file);
fclose(file);
free(data);
/* WTF did we just do */
printf("Copied:\n\tOld: %s\n\tNew: %s\n", oldLocation, newLocation);
if (bytes_written != length)
{
printf("Warning: an error occurred when writing to %s\n", newLocation);
}
}
bool FILESYSTEM_openDirectoryEnabled()