Hi,
Lots of users like the midas::odb interface for reading from the ODB in manalyzers. It currently doesn't 
work offline however without a few manual lines to tell midas::odb to read from the ODB copy in the run 
header. The code also gets a bit messy to work out the current filename and get midas::odb to reopen the 
file currently being processed. This would be much cleaner if manalyzer set this up automatically, and then 
user code could be written that is completely ignorant of whether it is running online or offline.

The change I suggest is in the `set_offline_odb` branch, commit 4ffbda6, which is simply:

diff --git a/manalyzer.cxx b/manalyzer.cxx
index 371f135..725e1d2 100644
--- a/manalyzer.cxx
+++ b/manalyzer.cxx
@@ -15,6 +15,7 @@
 
 #include "manalyzer.h"
 #include "midasio.h"
+#include "odbxx.h"
 
 //////////////////////////////////////////////////////////
 
@@ -2075,6 +2076,8 @@ static int ProcessMidasFiles(const std::vector<std::string>& files, const std::v
                if (!run.fRunInfo) {
                   run.CreateRun(runno, filename.c_str());
                   run.fRunInfo->fOdb = MakeFileDumpOdb(event->GetEventData(), event->data_size);
+                  // Also set the source for midas::odb in case people prefer that interface
+                  midas::odb::set_odb_source(midas::odb::STRING, std::string(event->GetEventData(), event-
>data_size));
                   run.BeginRun();
                }


It happens at the point where the ODB record is already available and requires no effort from the user to 
be able to read the ODB offline.

Thanks,

Mark.

> ....Before commit of this patch, can you confirm the RunInfo destructor
> deletes this ODB stuff from odbxx? manalyzer takes object life times very seriously.

The call stores the ODB string in static members of the midas::odb class. So these will have a lifetime of the process or until they're replaced by another 
call. When a midas::odb is instantiated it reads from these static members and then that data has the lifetime of that instance.

> Of course with this patch extending manalyzer to process two or more runs at the same time becomes impossible.

Yes, I hadn't realised that was an option. For that to work I guess the aforementioned static members could be made thread local storage, and 
processing of each run kept to a specific thread. Although I could imagine user code making assumptions and breaking, like storing a midas::odb as a 
class member or something.

Note that I missed doing the same for the end of run event, which should probably also be added.

Thanks,

Mark.

> ...I talked to KO so he agreed that yo then commit your proposed change of manalyzer 

Merged and pushed.

Thanks,

Mark.

Hi all,

last week I was running MIDAS with the commit 3ad98c5. Today I updated MIDAS and now all my watch functions are crashing. Attached I have a minimal example frontend of the problem.

In our software we have two functions one which sets up the ODB values of the frontend and another one which sets up all watch functions. So overall we connect two time to the ODB during fronend_init one time to create the values and one time to create the watch. In the example code a simple version of this setup is shown:

INT frontend_init() {

  cm_msg(MINFO, "frontend_init() setup", "Test FE");

  odb settings = {
    {"Test", 123},
    {"sub", {}}
  };
  settings.connect_and_fix_structure("/Equipment/Test FE/Settings");
  // settings.watch(watch); <-- this works without segmentation fault

  odb new_settings("/Equipment/Test FE/Settings");
  new_settings.watch(watch); // <-- here I am getting a segmentation fault

  return CM_SUCCESS;
}

When I directly set the watch everything runs fine however, when I create a new ODB object and use this one to set a watch I am getting the following segmentation fault:

Process 18474 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x34)
    frame #0: 0x000000010004fa38 test_fe`midas::odb::watch_callback(hDB=<unavailable>, hKey=<unavailable>, index=0, info=0x00006000002001c0) at odbxx.cxx:96:25 [opt]
   93  	      if (po->m_data == nullptr)
   94  	         mthrow("Callback received for a midas::odb object which went out of scope");
   95  	      midas::odb *poh = search_hkey(po, hKey);
-> 96  	      poh->m_last_index = index;
   97  	      po->m_watch_callback(*poh);
   98  	      poh->m_last_index = -1;
   99  	   }

Best,
Marius

Hello everybody,

I have a strange JS behavior. In one of my frontends I create a key in the ODB with:

db_create_key(hDB, 0, "Equipment/Switching/Variables/DATA_WRITE", TID_INT);

In my custom page I have a JS function which loops over an array and sets the
value of this key with:

for (i = 0; i < lines.length; i++) {
        modbset("/Equipment/Switching/Variables/DATA_WRITE[" + String(i) + "]",
parseInt(lines[i]));
}

After calling this function I have an array in the ODB now. For my understanding
calling an INT like an array shouldn't be possible. So is this dangerous to do?

Best regards,
Marius

> > for (i = 0; i < lines.length; i++) {
> >         modbset("/Equipment/Switching/Variables/DATA_WRITE[" + String(i) + "]", parseInt(lines[i]));
> > }
> 
> this is wrong.
> 
> a) you are programming javascript as if it were C/C++. You think this code wrote lines.length() values 
> to ODB, when what the code actually did is queued lines.length() RPC requests for later execution. 
> Eventually some time later, each RPC request will open a connection to mhttpd, send a request, wait 
> for mhtttpd to process it, etc. Where do you wait for the completion of all these RPCs before 
> proceeding as if all the data has been successfully written to ODB? (answer: you cannot, javascript 
> cannot "wait for things", instead you have to make chains of event handlers. javascript != C/C++. 
> They are completely different).

--> Following your discussion about async. functions I will change this part of the code and make chains of
event handlers.

> b)  you should write the whole array in one operation instead of looping over each element. see 
> mjsonrpc_db_paste() and example.html.

--> In the midas back-end I never created an array. I created an INT in the ODB with db_create_key(hDB, 0,
"Equipment/Switching/Variables/DATA_WRITE", TID_INT). By using modset in javascript and parsing the string
"/Equipment/Switching/Variables/DATA_WRITE[" + String(i) + "]" I call it like an array and it shows up like an
array in the ODB. So for explaining it a bit better how the value changes in the ODB take this pseudo code
example:

// midas part //
> int a = 1; // this is more or less what I think db_create_key is doing in the ODB
// midas part //

// ODB //
> print(a) // this prints me 1 and this is also the value what I see in the ODB
// ODB //

// javascript part //
> for int i in [1,2,3,4] do 
> modset(a[i], i) // for simplification I don't use event handlers here
> end for
// javascript part //

// ODB //
> print(a) // now I see [1,2,3,4]
// ODB //

This example violates type safety. I know that javascript is not type safe. According to this I would like
to know if this behavior is wanted or why there is no bounds checking?

> I do not understand your question about "calling an INT like an array".
--> Here I mean that I call the variable in the ODB via string passing, like I would call a variable, which is
an array. I don't speak about function calls.

> parseInt() (defined where?)
--> This is a global JavaScript function (https://www.w3schools.com/jsref/jsref_obj_global.asp)

Cheers,
Marius

Dear all,

we are trying to build Midas events on FPGAs and send them directly to the midas
ring buffer via copy_n. According to the wiki
https://midas.triumf.ca/MidasWiki/index.php/Event_Structure Event Data Size is:
"The event data size contains the size of the event in bytes excluding the
header." and All Bank Size is: "Size in bytes of the following data plus the
size of the bank header". So are they actually the same or what header is the
header in the first sentence also the bank header?

Cheers,
Marius

 

Dear all,

we creating Midas events directly inside a FPGA and send them off via DMA into the PC RAM. For reading out this RAM via Midas the FPGA sends as a pointer where it has written the last 4kB of data. We use this pointer for telling the ring buffer of midas where the new events are. The buffer looks something like:

// event 1
dma_buf[0] = 0x00000001; // Trigger and Event ID
dma_buf[1] = 0x00000001; // Serial number
dma_buf[2] = TIME; // time
dma_buf[3] = 18*4-4*4; // event size
dma_buf[4] = 18*4-6*4; // all bank size
dma_buf[5] = 0x11; // flags
// bank 0
dma_buf[6] = 0x46454230; // bank name
dma_buf[7] = 0x6; // bank type TID_DWORD
dma_buf[8] = 0x3*4; // data size
dma_buf[9] = 0xAFFEAFFE; // data
dma_buf[10] = 0xAFFEAFFE; // data
dma_buf[11] = 0xAFFEAFFE; // data
// bank 1
dma_buf[12] = 0x1; // bank name
dma_buf[12] = 0x46454231; // bank name
dma_buf[13] = 0x6; // bank type TID_DWORD
dma_buf[14] = 0x3*4; // data size
dma_buf[15] = 0xAFFEAFFE; // data
dma_buf[16] = 0xAFFEAFFE; // data
dma_buf[17] = 0xAFFEAFFE; // data

// event 2
.....

dma_buf[fpga_pointer] = 0xXXXXXXXX;


And we do something like:

while{true}
   // obtain buffer space
   status = rb_get_wp(rbh, (void **)&pdata, 10);
   fpga_pointer = fpga.read_last_data_add();

   wlen = last_fpga_pointer - fpga_pointer; \\ in 32 bit words
   copy_n(&dma_buf[last_fpga_pointer], wlen, pdata);
   rb_status = rb_increment_wp(rbh, wlen * 4); \\ in byte

   last_fpga_pointer = fpga_pointer;

Leaving the case out where the dma_buf wrap around this works fine for a small data rate. But if we increase the rate the fpga_pointer also increases really fast and wlen gets quite big. Actually it gets bigger then max_event_size which is checked in rb_increment_wp leading to an error. 

The problem now is that the event size is actually not to big but since we have multi events in the buffer which are read by midas in one step. So we think in this case the function rb_increment_wp is comparing actually the wrong thing. Also increasing the max_event_size does not help.

Remark: dma_buf is volatile so memcpy is not possible here.

Cheers,
Marius

We also agree and found the problem now. Since we build everything (MIDAS Event Header, Bank Header, Banks etc.) in the FPGA we had some struggle with the MIDAS data format (http://lmu.web.psi.ch/docu/manuals/bulk_manuals/software/midas195/html/AppendixA.html). We thought that only the MIDAS Event needs to be aligned to 64 bit but as it turned out also the bank data (Stefan updated the wiki page already) needs to be aligned. Since we are using the BANK32 it was a bit unclear for us since the bank header is not 64 bit aligned. But we managed this now by adding empty data and the system is running now.

Our setup looks like this:

- mfe.cxx multithread equipment
- mfe readout thread grabs pointer from dma ring buffer 
- since the dma buffer is volatile we do copy_n for transforming the data to MIDAS 
- the data is already in the MIDAS format so done from our side :)
- mfe readout thread increments the ring buffer
- mfe main thread grabs events from ring buffer, sends them to the mserver

From the firmware side we have an Arria 10 development board and 

But now I am curious, which DMA controller you use? The Altera or Xilinx PCIe block with the vendor supplied DMA driver? Or you do DMA on an ARM SoC FPGA? (no PCI/PCIe, 
different DMA controller, different DMA driver).

I am curious because we will be implementing pretty much what you do on ARM SoC FPGAs pretty soon, so good to know
if there is trouble to expect.

But I will probably use the tmfe.h c++ frontend and a "pure c++" ring buffer instead of mfe.cxx and the midas "rb" ring buffer.

(I did not look at your code at all, there could be a bug right there, this ring buffer stuff is tricky. With luck there is no bug
in your dma driver. The dma drivers for our vme bridges did do have bugs).

K.O.

We also agree and found the problem now. Since we build everything (MIDAS Event Header, Bank Header, Banks etc.) in the FPGA we had some struggle with the MIDAS data format (http://lmu.web.psi.ch/docu/manuals/bulk_manuals/software/midas195/html/AppendixA.html). We thought that only the MIDAS Event needs to be aligned to 64 bit but as it turned out also the bank data (Stefan updated the wiki page already) needs to be aligned. Since we are using the BANK32 it was a bit unclear for us since the bank header is not 64 bit aligned. But we managed this now by adding empty data and the system is running now.

Our setup looks like this:

Software:
- mfe.cxx multithread equipment
- mfe readout thread grabs pointer from dma ring buffer 
- since the dma buffer is volatile we do copy_n for transforming the data to MIDAS 
- the data is already in the MIDAS format so done from our side :)
- mfe readout thread increments the ring buffer
- mfe main thread grabs events from ring buffer, sends them to the mserver

Firmware:
- Arria 10 development board
- Altera PCIe block
- Own DMA engine since we are doing burst writing DMA with PCIe 3.0. 
- Own device driver
- no interrupts 

If you have more questions fell free to ask.

> > We also agree and found the problem now.
> 
> Good. what was wrong?
> 
> > - Own DMA engine since we are doing burst writing DMA with PCIe 3.0. 
> > - Own device driver
> 
> Scary stuff.
> 
> > - no interrupts 
> 
> Right. Best I can tell, interrupts no longer useful in Linux - interrupt handler cannot do any real work, has to hand off to a kernel thread, resulting
> in so much latency and overhead that one might as well poll for the data... And for DMA data transfers, the data rate is well known,
> so easy to predict how long the DMA will run for and sleep for that amount of time instead of waiting for an interrupt.
> 
> K.O.

So the problem was that we assumed that the bank (with the header) needs to be 64bit aligned. Even more we aligned the hole Midas event to 256bit in the fpga since we have a  250mhz x 256 Bit interface for PCIe. But then we saw that you align the bank data to 64bit -> crash of mdump etc. For now we generate the data on the FPGA in the „old“ Midas format. So having a flag for changing to a different alignment would be actually really nice. 

Cheers,
Marius

Hello everybody,

I am really appreciate the development of the new odb++ API. So I directly started to rewrite the code for the Mu3e DAQ system.

I have a view questions / suggestions which came up during my work so fare:

1. The documentation seems to be quite new so there are some variables wrong named and small typo stuff. I would like to fix them. Should I request for an account or what else is needed to change them?

2. When I create an ODB structure with the new API I do for example:

    midas::odb stream_settings = {
            {"Test_odb_api", {
                                      {"Divider", 1000},     // int
                                      {"Enable", false},     // bool
                              }},
    };
    stream_settings.connect("/Equipment/Test/Settings", true);

and with 

midas::odb datagen("/Equipment/Test/Settings/Test_odb_api");
std::cout << "Datagenerator Enable is " << datagen["Enable"] << std::endl;

I am getting back false. Which looks nice but when I look into the odb via the browser the value is actually "y" meaning true which is stange. I added my frontend where I cleaned all function leaving only the frontend_init() one where I create this key. Its a cuda program but since I clean everything no cuda function is called anymore.

Thank you again for the nice development!

Cheers,
Marius 

Hi Stefan,

your test program was only working for me after I changed the following lines inside the odbxx.cpp

diff --git a/src/odbxx.cxx b/src/odbxx.cxx
index 24b5a135..48edfd15 100644
--- a/src/odbxx.cxx
+++ b/src/odbxx.cxx
@@ -753,7 +753,12 @@ namespace midas {
          }
       } else {
          u_odb u = m_data[index];
-         status = db_set_data_index(m_hDB, m_hKey, &u, rpc_tid_size(m_tid), index, m_tid);
+         if (m_tid == TID_BOOL) {
+             BOOL ss = bool(u);
+             status = db_set_data_index(m_hDB, m_hKey, &ss, rpc_tid_size(m_tid), index, m_tid);
+         } else {
+             status = db_set_data_index(m_hDB, m_hKey, &u, rpc_tid_size(m_tid), index, m_tid);
+         }
          if (m_debug) {
             std::string s;
             u.get(s);

Likely not the best fix but otherwise I was always getting after running the test program:

[ODBEdit,INFO] Program ODBEdit on host localhost started
[local:Default:S]/>cd Equipment/Test/Settings/Test_odb_api/
key not found
makoeppe@office ~/mu3e/online/online (git)-[odb++_api] % test_connect
Created ODB key /Equipment/Test/Settings
Created ODB key /Equipment/Test/Settings/Test_odb_api
Created ODB key /Equipment/Test/Settings/Test_odb_api/Divider
Set ODB key "/Equipment/Test/Settings/Test_odb_api/Divider" = 1000
Created ODB key /Equipment/Test/Settings/Test_odb_api/Enable
Set ODB key "/Equipment/Test/Settings/Test_odb_api/Enable" = false
Get definition for ODB key "/Equipment/Test/Settings/Test_odb_api"
Get definition for ODB key "/Equipment/Test/Settings/Test_odb_api/Divider"
Get ODB key "/Equipment/Test/Settings/Test_odb_api/Divider": 1000
Get definition for ODB key "/Equipment/Test/Settings/Test_odb_api/Enable"
Get ODB key "/Equipment/Test/Settings/Test_odb_api/Enable": false
Get definition for ODB key "/Equipment/Test/Settings/Test_odb_api/Divider"
Get ODB key "/Equipment/Test/Settings/Test_odb_api/Divider": 1000
Get definition for ODB key "/Equipment/Test/Settings/Test_odb_api/Enable"
Get ODB key "/Equipment/Test/Settings/Test_odb_api/Enable": false
Datagenerator Enable is Get ODB key "/Equipment/Test/Settings/Test_odb_api/Enable": false
false
makoeppe@office ~/mu3e/online/online (git)-[odb++_api] % odbedit
[ODBEdit,INFO] Program ODBEdit on host localhost started
[local:Default:S]/>cd Equipment/Test/Settings/Test_odb_api/
[local:Default:S]Test_odb_api>ls
Divider                         1000
Enable                          y 

> > I am getting back false. Which looks nice but when I look into the odb via the browser the value is actually "y" meaning true which is stange. 
> > I added my frontend where I cleaned all function leaving only the frontend_init() one where I create this key. Its a cuda program but since 
> > I clean everything no cuda function is called anymore.

Hi Stefan,

I agree with your explanation about the size of BOOL and bool. 

I checked the program also on my Raspberry and there the old code works like on your mac. I don't really understand 
why the behavior is different for my system. The initializing of the union should also work for my system. 

At the moment I am using:

Arch Linux
Linux office 5.4.42-1-lts #1 SMP Wed, 20 May 2020 20:42:53 +0000 x86_64 GNU/Linux
gcc version 10.1.0 (GCC)

One thing which makes me a bit suspicious is that if I do:

u_odb u = m_data[index];
char dest[rpc_tid_size(m_tid)];
memcpy(dest, &u, rpc_tid_size(m_tid));

Clion tells me "Clang-Tidy: Undefined behavior, source object type 'midas::u_odb' is not TriviallyCopyable". 

I am not sure if this is the problem since I am not so familiar with this TriviallyCopyable. I need to further investigate here.

So fare the update from my side.

Cheers,
Marius

> Hi Marius,
> 
> your fix is good. Thanks for digging out this deep-lying issue, which would have haunted us if we would not fix it. 
> The problem is that in midas, the "BOOL" type is 4 Bytes long, actually modelled after MS Windows. Now I realized
> that in c++, the "bool" type is only 1 Byte wide. So if we do the memcopy from a "c++ bool" to a "MIDAS BOOL", we
> always copy four bytes, meaning that we copy three Bytes beyond the one-byte value of the c++ bool. So your fix
> is absolutely correct, and I added it in one more space where we deal with bool arrays, where we need the same.
> 
> What I don't understand however is the fact why this fails for you. The ODB values are stored in the C union under
> 
> union {
>   ...
>   bool m_bool;
>   double m_double;
>   std::string *m_string;
>   ...
> }
> 
> Now the C compiler puts all values at the lowest address, so m_bool is at offset zero, and the string pointer reaches
> over all eight bytes (we are on 64-bit OS).
> 
> Now when I initialize this union in odbxx.h:66, I zero the string pointer which is the widest object:
> 
>   u_odb() : m_string{} {};
> 
> which (at least on my Mac) sets all eight bytes to zero. If I then use the wrong code to set the bool value to the ODB 
> in odbxx.cxx:756, I do 
> 
>   db_set_data_index(... &u, rpc_tid_size(m_tid), ...);
> 
> so it copies four bytes (=rpc_tid_size(TID_BOOL)) to the ODB. The first byte should be the c++ bool value (0 or 1),
> and the other three bytes should be zero from the initialization above. Apparently on your system, this is not
> the case, and I would like you to double check it. Maybe there is another underlying problem which I don't understand
> at the moment but which we better fix.
> 
> Otherwise the change is committed and your code should work. But we should not stop here! I really want to understand
> why this is not working for you, maybe I miss something.
> 
> Best,
> Stefan
> 
> > Hi Stefan,
> > 
> > your test program was only working for me after I changed the following lines inside the odbxx.cpp
> > 
> > diff --git a/src/odbxx.cxx b/src/odbxx.cxx
> > index 24b5a135..48edfd15 100644
> > --- a/src/odbxx.cxx
> > +++ b/src/odbxx.cxx
> > @@ -753,7 +753,12 @@ namespace midas {
> >           }
> >        } else {
> >           u_odb u = m_data[index];
> > -         status = db_set_data_index(m_hDB, m_hKey, &u, rpc_tid_size(m_tid), index, m_tid);
> > +         if (m_tid == TID_BOOL) {
> > +             BOOL ss = bool(u);
> > +             status = db_set_data_index(m_hDB, m_hKey, &ss, rpc_tid_size(m_tid), index, m_tid);
> > +         } else {
> > +             status = db_set_data_index(m_hDB, m_hKey, &u, rpc_tid_size(m_tid), index, m_tid);
> > +         }
> >           if (m_debug) {
> >              std::string s;
> >              u.get(s);
> > 
> > Likely not the best fix but otherwise I was always getting after running the test program:
> > 
> > [ODBEdit,INFO] Program ODBEdit on host localhost started
> > [local:Default:S]/>cd Equipment/Test/Settings/Test_odb_api/
> > key not found
> > makoeppe@office ~/mu3e/online/online (git)-[odb++_api] % test_connect
> > Created ODB key /Equipment/Test/Settings
> > Created ODB key /Equipment/Test/Settings/Test_odb_api
> > Created ODB key /Equipment/Test/Settings/Test_odb_api/Divider
> > Set ODB key "/Equipment/Test/Settings/Test_odb_api/Divider" = 1000
> > Created ODB key /Equipment/Test/Settings/Test_odb_api/Enable
> > Set ODB key "/Equipment/Test/Settings/Test_odb_api/Enable" = false
> > Get definition for ODB key "/Equipment/Test/Settings/Test_odb_api"
> > Get definition for ODB key "/Equipment/Test/Settings/Test_odb_api/Divider"
> > Get ODB key "/Equipment/Test/Settings/Test_odb_api/Divider": 1000
> > Get definition for ODB key "/Equipment/Test/Settings/Test_odb_api/Enable"
> > Get ODB key "/Equipment/Test/Settings/Test_odb_api/Enable": false
> > Get definition for ODB key "/Equipment/Test/Settings/Test_odb_api/Divider"
> > Get ODB key "/Equipment/Test/Settings/Test_odb_api/Divider": 1000
> > Get definition for ODB key "/Equipment/Test/Settings/Test_odb_api/Enable"
> > Get ODB key "/Equipment/Test/Settings/Test_odb_api/Enable": false
> > Datagenerator Enable is Get ODB key "/Equipment/Test/Settings/Test_odb_api/Enable": false
> > false
> > makoeppe@office ~/mu3e/online/online (git)-[odb++_api] % odbedit
> > [ODBEdit,INFO] Program ODBEdit on host localhost started
> > [local:Default:S]/>cd Equipment/Test/Settings/Test_odb_api/
> > [local:Default:S]Test_odb_api>ls
> > Divider                         1000
> > Enable                          y 
> > 
> > > > I am getting back false. Which looks nice but when I look into the odb via the browser the value is actually "y" meaning true which is stange. 
> > > > I added my frontend where I cleaned all function leaving only the frontend_init() one where I create this key. Its a cuda program but since 
> > > > I clean everything no cuda function is called anymore.

Hi Stefan,

I played around with the code a bit more and I found out that if I do:

midas::odb test_settings = {{"Enable", false}};
test_settings.connect("/Equipment/Test/Test", true);

The correct value ends up in the odb. In this case an u_odb instance is created
with a clean m_string. But if I run the other code an odb instanceo is created and
the values of m_data are set in

odbxx.h:
        odb(std::initializer_list<std::pair<const char *, midas::odb>> list) : odb() {...

This values are comming from u_odb instances since the code does:

odbxx.h:
        auto o = new midas::odb(element.second);

and then

odbxx.h:
        odb(T v):odb() {                                                                                                                                                                                                                                   
           m_num_values = 1;                                                                                                                                                                                                             
           m_data = new u_odb[1]{v};                                                                                                                                                                                                                
           m_tid = m_data[0].get_tid();                                                            
           m_data[0].set_parent(this);                                                         
        }

and looking at 

odbxx.h:
        u_odb(bool v) : m_bool{v}, m_tid{TID_BOOL}, m_parent_odb{nullptr} {};   

only m_bool is set for this instance meaning that only the first byte gets a value 
(still having only 1 byte for bool in c++). If I check m_string inside the u_odb::get function
 of this instance I am getting for a bool (I set false) stuff like 0x7f6633f67a00 and for an int 
(I set the int to 1000) 0x7f66000003e8. Since the size of BOOL is larger I am getting the 
wrong value. I checked this also on openSUSE having the same behavior.

Like you I am not getting this problem on my Mac. What compiler flags do you use on your Mac?

Cheers,
Marius

Hi Stefan,

now everything works well (Tested on: OpenSuse and Arch Linux) :) 

Thank you for the fix.

Cheers,
Marius

> Hi Marius,
> 
> thanks for your help, you identified the problematic location. I changed that to
> 
>    u_odb(bool v) : m_tid{TID_BOOL}, m_parent_odb{nullptr} {m_string = nullptr; m_bool = v;};
> 
> which should initialize the full 8 bytes of the u_odb union. I committed to develop. Can you 
> please give it a try?
> 
> Best,
> Stefan
> 
> 
> > and looking at 
> > 
> > odbxx.h:
> >         u_odb(bool v) : m_bool{v}, m_tid{TID_BOOL}, m_parent_odb{nullptr} {};   
> > 
> > only m_bool is set for this instance meaning that only the first byte gets a value 
> > (still having only 1 byte for bool in c++). If I check m_string inside the u_odb::get function
> >  of this instance I am getting for a bool (I set false) stuff like 0x7f6633f67a00 and for an int 
> > (I set the int to 1000) 0x7f66000003e8. Since the size of BOOL is larger I am getting the 
> > wrong value. I checked this also on openSUSE having the same behavior.

Hi everyone,

I am currently trying to access a ROOT file produced by manalyzer. By calling JSROOT.openFile("MIDAS_DOMAIN/outputRUN.root"). I can download the rootfile via MIDAS_DOMAIN/outputRUN.root. Using JSROOT.openFile results in an 501 error, 
since the request feature is not provided. Using a simple API and uploading outputRUN.root there worked fine (when the run finised). 

Is there a way to use JSROOT.openFile with the current analyzed root file in Midas (so during the run)? I know that one can access histograms of the THttpServer via JSON but I need to get the full root tree.

Cheers,
Marius

Thank you for the answer :)

> At some point I would like to provide a function to "get" TAFlowEvent objects so you can do things
> like event displays in javascript. But I need a c++ to json serializer and standard c++ does not have it.
> So I will have to use the clang serializer (also used by ROOT) and it will take me a few days
> to figure it out.

That sounds exactly what I was searching for. Because I wanted to create an interface between rootana and 
an event display build in javascript. Since all I tried did not really worked with the current rootana
I have now a "solution". I use the MIDAS python client, read directly events from the MIDAS buffer and provided
the events in a JSON format with the python flask API. Since the rendering of the event display is the bottleneck 
and I only need a view events to display this solution worked really well for me. Maybe having such a JSON API of 
the event buffer in MIDAS directly would also work for most of the event display applications or other simple javescript 
applications (my opinion).

> If you figure out the missing bits that need to be added to our code,
> please post them here or submit them as a pull request or a bug report in bitbucket.

One of the problems I had was the CORS domain of the THttpServer. In manalyzer:1894 you do 
sprintf(str, "http:127.0.0.1:%d", httpPort); but there are additional options for the THttpServer (like "?cors=DOMAIN").
So maybe a flag while starting manalyzer passing such options would be nice. I will create a pull request passing them later.

> Also it would be good if you can provide a code example of "openFile" working elsewhere
> but not with manalyzer, if I can run it, maybe I can figure out what's missing. But lacking
> some example code, there is nothing for me to hack at.

The problem is that it was not even running on simple THttpServer using interactive root:

    serv = new THttpServer("http:8088?cors=*");
    TFile *_file0 = TFile::Open("example_root.root")
    serv->Register("File", _file0);

So I tried just saving the file in the $MIDAS_DIR and tried to use mserver with JSROOT.openFile. I attached the html file and 
a test root file.

Cheers,
Marius

> would this work for what you are doing?

Yes, having such a function would be perfect for the applications I have a the moment.

> (this is not good enough if data has to be pre-digested by c++ analysis in rootana)

Also agree, if one wants to have a more sophisticated applications it is definitely needed to preprocess the data.

Cheers,
Marius

> Does anybody actually use "find_package(midas)", does it actually work for anybody?

What we do is to include midas as a submodule and than we call find_package:

    add_subdirectory(midas)
    list(APPEND CMAKE_PREFIX_PATH ${CMAKE_CURRENT_SOURCE_DIR}/midas)
    find_package(Midas REQUIRED)

For us it works fine like this but we kind of always compile Midas fresh and don't use a version on our system (keeping the newest version). 

Without the find_package the build does not work for us.