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This overloads the meaning of RUST_LOG to also allow 'module.submodule' or 'module.somethingelse=2' forms. The first turn on all logging for a module (loglevel 3), the second sets its loglevel to 2. Log levels are: 0: Show only errors 1: Errors and warnings 2: Errors, warnings, and notes 3: Everything, including debug logging Right now, since we only have one 'log' operation, everything happens at level 1 (warning), so the only meaningful thing that can be done with the new RUST_LOG support is disable logging (=0) for some modules. TODOS: * Language support for logging at a specific level * Also add a log level field to tasks, query the current task as well as the current module before logging (log if one of them allows it) * Revise the C logging API to conform to this set-up (globals for per-module log level, query the task level before logging, stop using a global mask) Implementation notes: Crates now contain two extra data structures. A 'module map' that contains names and pointers to the module-log-level globals for each module in the crate that logs, and a 'crate map' that points at the crate's module map, as well as at the crate maps of all external crates it depends on. These are walked by the runtime (in rust_crate.cpp) to set the currect log levels based on RUST_LOG. These module log globals are allocated as-needed whenever a log expression is encountered, and their location is hard-coded into the logging code, which compares the current level to the log statement's level, and skips over all logging code when it is lower.
This is a compiler and suite of associated libraries and documentation for the Rust programming language. See LICENSE.txt for terms of copyright and redistribution. See http://github.com/graydon/rust for current development page.