CODEWITHSUNDEEP
rustlldb
ender maz
ender maz

Reputation: 393

How do I see a user-friendly format when debugging chrono::DateTime in vscode-lldb?

The debugger shows this for DateTime structs:

enter image description here

After looking at the docs for lldb to see how to format it, I see I can format integers as hex:

type format add -f hex i32

I tried something similar for DateTime

type format add --format hex chrono::datetime::DateTime<chrono::offset::utc::Utc>

It's not picking up the chrono type even though frame variable shows this as the type. Even after this step is done, not sure how to parse the date to string.

Upvotes: 3

Views: 921

Answers (2)

ender maz
ender maz

Reputation: 393

Using @Jim Ingham hints in the other answer and a touchup to this formula

  1. Modify the launch.json file by adding
"initCommands": [
    "command source '${workspaceFolder}/my_type_formatters'"
]
  1. Add the following file called my_type_formatters to the root of the project.
command script import simd.py 

type summary add -F simd.GetSummary chrono::datetime::DateTime<chrono::offset::utc::Utc>
  1. Add a simd.py file to the root of the project with:
from datetime import datetime,timedelta


def GetSummary(valobj, internal_dict):
    ymdf = valobj.GetChildMemberWithName('datetime').GetChildMemberWithName('date').GetChildMemberWithName('ymdf').GetValue();
    secs = valobj.GetChildMemberWithName('datetime').GetChildMemberWithName('time').GetChildMemberWithName('secs').GetValue();
    year = int(ymdf) >> 13  
    day_of_year = (int(ymdf) & 8191) >> 4;
    date = datetime(year -1, 12, 31) + timedelta(days=day_of_year) + timedelta(seconds=int(secs))
    return date.strftime('%Y-%m-%d %H:%M:%S')

Result:

enter image description here

Upvotes: 4

Jim Ingham
Jim Ingham

Reputation: 27173

lldb has three stages of customization for printing values of a given type. The simplest is "type format" which specifies the format to use (hex, chars, etc) to display scalar entities. The second is "type summary" which allows you to print a one-line string summary of the value. The third is "type synthetic" which allows you to present a value as some kind of structured object (e.g. making std::vector look like an vector of values rather than its internal form.)

You want to add a "type summary" for this type that parses the data and prints it as a human-readable string.

Upvotes: 1

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