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digitalmars.D.learn - GC and sensible data read by File

reply frame <frame86 live.com> writes:
Hello,

I'm new to D and try to find out a memory leak in my program. I 
inspected the private bytes with VmMap on Windows to see which 
data is still kept.

Besides the actual memory leak I was surprised to find out there 
are contents of my previoulsy read configuration INI file.

So my question is: Is this expected behaviour? Why does the GC 
then not overwrite the contents with 0? Or did I something wrong 
in my function or does File not clear the data afterwards? And if 
so, how can I read sensible data from a file with standard 
methods which should not kept in memory?

I also tried manually GC.free() on buf and other places but still 
same result.

Basically this (removed some encforce() statements) and do not 
show Converter method here because the string in memory is raw 
string like a INI-comment which is never passed to my converter, 
so it's not relevant and cannot cause the problem.

Variant[string][string] parse() {


         size_t lineNr;
         char[] buf;

         string sectionName;
         string keyName;
         Variant[string][string] sections;

         auto fp = File(_fileName);
         while (!fp.eof()) {
             buf.length = 0;
             fp.readln(buf);

             string line = to!string(buf).trim();

             ++lineNr;

             // filter out empty lines
             if (line.length == 0)
                 continue;

             // filter out comments
             if (line.startsWith(";"))
                 continue;

             if (line.startsWith("[")) {
                 // section start / previous section complete
                 sectionName = line.trim("[]");
                 continue;
             }

             // regular entry
             Variant v;
             ptrdiff_t sepPos = line.indexOf("=");

             keyName = to!string(line[0 .. sepPos]).trim();
             bool isArrayEntry = keyName.indexOf("[]") > -1 && 
keyName.endsWith("]");

             string tmpVal = to!string(line[sepPos + 1 .. 
$]).trim();

             // trim text delimiter chars, if any
             tmpVal = tmpVal.trim("'\"");

             // if array, just append to existing value or create 
it
             if (isArrayEntry) {
                 keyName = keyName.trim("[]");

                 // array is always considered as string
                 // other values makes no sense in this syntax
                 string oldVal;

                 if (auto sectionPtr = sectionName in sections) {
                     if (auto keyPtr = keyName in *sectionPtr) {
                         oldVal = (*keyPtr).get!(string);
                     }
                 }

                 v = Variant(oldVal ~ tmpVal);
             }
             else {
                 v = Converter.autoConvertFromString(tmpVal);
             }

             sections[sectionName][keyName] = v;
         }

         return sections;
     }
Oct 04 2020
next sibling parent reply frame <frame86 live.com> writes:
So I found out that there is nothing wrong with the method as in 
a test environment the allocated memory block is removed after 
GC.minimize().

Still need to find out why other blocks are not released.

However, is there a way to debug currently allocated variables by 
the GC?
Oct 05 2020
parent reply ryuukk_ <ryuukk_ gmail.com> writes:
On Monday, 5 October 2020 at 11:14:47 UTC, frame wrote:
 So I found out that there is nothing wrong with the method as 
 in a test environment the allocated memory block is removed 
 after GC.minimize().

 Still need to find out why other blocks are not released.

 However, is there a way to debug currently allocated variables 
 by the GC?
``` "buildTypes": { "debug_gc": { "buildOptions": ["debugMode", "debugInfo"], "dflags": ["-profile=gc"] } }, ``` and run using: ``dub run --compiler=dmd --build=debug_gc`` once program exit it'll create a log file: ``profilegc.log`` with all allocations
Oct 05 2020
parent frame <frame86 live.com> writes:
On Monday, 5 October 2020 at 11:28:56 UTC, ryuukk_ wrote:
 On Monday, 5 October 2020 at 11:14:47 UTC, frame wrote:
 So I found out that there is nothing wrong with the method as 
 in a test environment the allocated memory block is removed 
 after GC.minimize().

 Still need to find out why other blocks are not released.

 However, is there a way to debug currently allocated variables 
 by the GC?
``` "buildTypes": { "debug_gc": { "buildOptions": ["debugMode", "debugInfo"], "dflags": ["-profile=gc"] } }, ``` and run using: ``dub run --compiler=dmd --build=debug_gc`` once program exit it'll create a log file: ``profilegc.log`` with all allocations
I tried that but it gives me only a profile of used allocations over all time. What I really need is a debug feature to see which variable/pointer is currently known by the GC or at least which one was still referenced by end of the program.
Oct 24 2020
prev sibling parent Imperatorn <johan_forsberg_86 hotmail.com> writes:
On Sunday, 4 October 2020 at 12:10:39 UTC, frame wrote:
 Hello,

 I'm new to D and try to find out a memory leak in my program. I 
 inspected the private bytes with VmMap on Windows to see which 
 data is still kept.

 [...]
The GC doesn't zero it out, so that's expected.
Oct 24 2020