Eliminate the boilerplate of declaring this and assigning memory to it, which is the same for the vast majority of object creations.
Keep the old version of the macro as OBJ_NEW_BASE_BEGIN() for a few exceptions in the core code and (mostly) in the tests.
Allocating memory made these functions simpler but it meant that memory was leaking into the calling context when logging was enabled. It is not clear that this was an issue but it seems that trace level logging could result it a lot of memory usage depending on the use case.
This also makes it possible to audit allocations returned to the calling context, which will be done in a followup commit.
Also rename objToLog() to objNameToLog() since it seemed logical to name the new function objToLog().
This should make it a little clearer what the variable (VR) macros are doing since the declaration/definition cannot both be set to extern (but functions can).
Splitting the variable macros out also allows them to be changed in the future with little churn, while changing the function macro creates a large amount of churn.
This is immediately useful because it will detect any extern'd functions or variables that are not being used. It also detects functions or variables that are declared but not defined.
If a FV/VR_EXTERN macro is missing it will be detected either because of a mismatch in the declaration/definition or because a new defined symbol will appear in the nm test.
Eventually the unity build will be used to create a more optimized pgbackrest binary but that will need to wait.
Each mem context can track child contexts, allocations, and a callback. Before this change memory was allocated for tracking all three even if they were not used for a particular context. This made mem contexts unsuitable for String and Variant objects since they are plentiful and need to be as small as possible.
This change allows mem contexts to be configured to track any combination of child contexts, allocations, and a callback. In addition, the mem context can be configured to track a single child context and/or allocation, which saves memory and is a common use case.
Another benefit is that Variants can own objects (e.g. KeyValue) that they encapsulate. All of this makes memory accounting simpler because mem contexts have names while allocations do not. No more memory is used than before since Variants and Strings still had to store the memory context they were originally allocated in so they could be easily freed.
Update the String and Variant objects to use this new functionality. The custom strFree() and varFree() functions are no longer required and can now be a wrapper around objFree().
Lastly, this will allow strMove() and varMove() to be implemented and used in cases where strDup() and varDup() are being used to move a String or Variant to a new context. Since this will be a bit noisy it is saved for a future commit.
This allows code to run after the return type has been generated in the case where it is an expression.
No new functionality here yet, but this will be used by a future commit that audits memory usage.
Packs support stronger typing than JSON and are more efficient. For the small result sets that we deal with efficiency is probably not very important, but this removes another place where we are using JSON instead of Pack.
Push checking for result struct (e.g. single row) down into PgClient since it has easy access to this information rather than needing to parse the result set to find out.
Refactor all code downstream that depends on PgClient results.
A CHECK() worked exactly like ASSERT() except that it was compiled into production code. However, over time many checks have been added that should not throw AssertError, which should be reserved for probable coding errors.
Allow the error code to be specified so other error types can be thrown. Also add a human-readable message since many of these could be seen by users even when there is no coding error.
Update coverage exceptions for CHECK() to match ASSERT() since all conditions will never be covered.
The vast majority of Strings are never modified so for most cases allocate memory for the string with the object. This results in one allocation in most cases instead of two. Use strNew() if strCat*() functions are needed.
Update varNewStr() in the same way since String Variants can never be modified. This results in one allocation in all cases instead of three. Also update varNewStrZ() to use STR() instead of strNewZ() to save two more allocations.
The primary benefit is that objects can allocate memory for their struct with the context, which saves an additional allocation and makes it easier to read context/allocation dumps. Also, the memory context does not need to be stored with the object since it can be determined using the object pointer.
Object pointers cannot be moved, so this means whatever additional memory is allocated cannot be resized. That makes the additional memory ideal for object structs, but not so much for allocating a list that might change size.
Mem contexts can no longer be reused since they will probably be the wrong size so their memory is freed on memContextFree(). This still means fewer allocations and frees overall.
Interfaces still need to be freed by mem context so the old objMove() and objFree() have been preserved as objMoveContext() and objFreeContext(). This will be addressed in a future commit.
Replace all instances of strNew("") with strNew() and use strNewZ() for non-empty zero-terminated strings. Besides saving a useless parameter, this will allow smarter memory allocation in a future commit by signaling intent, in general, to append or not.
In the tests use STRDEF() or VARSTRDEF() where more appropriate rather than blindly replacing with strNewZ(). Also replace strLstAdd() with strLstAddZ() where appropriate for the same reason.
Inline functions are more efficient and if they are not used are automatically omitted from the binary.
This also makes the implementation of these functions easier to find and removes the need for a declaration. That is, the complete implementation is located in the header rather than being spread between the header and C file.
OBJECT_DEFINE_MOVE() and OBJECT_DEFINE_FREE() will be replaced with inlines so this would be the only macro left that is constructing functions.
It is not a great pattern anyway since it makes it hard to find the function implementation.
The original intention was to enclose complex code in braces but somehow braces got propagated almost everywhere.
Document the standard for braces in switch statements and update the code to reflect the standard.
There is not a lot to be done in this case since it looks like PostgreSQL disconnected while the query was running, but at least improve the error message and remove the assert, which indicates a coding error.
We use the Z suffix in many functions to indicate that we are expecting a zero-terminated string so make this function conform to the pattern.
As a bonus the new name is a bit shorter, which is a good quality in a commonly-used function.
This has been the policy for some time but due to migration pressure only new functions and refactors have been following this rule. Now it seems sensible to make a clean sweep and move all the comments that have not been moved already (i.e. most of them).
Only obvious typos and gross inaccuracies in the comments have been fixed. For this most part this was a copy and paste operation.
Useless comments, e.g. "New object", were not copied. Even so, there are surely many deficient comments left.
Some rearranging was done where needed and functions were placed in the proper sections, e.g. "Constructors", "Functions", etc.
A few function prototypes were found that not longer had an implementation. These were removed, but there may be more.
The coding document has been updated to reflect this policy, which is not new but has never been documented.
Previously memNew() used memset() to initialize all struct members to 0, NULL, false, etc. While this appears to work in practice, it is a violation of the C specification. For instance, NULL == 0 must be true but neither NULL nor 0 must be represented with all zero bits.
Instead use designated initializers to initialize structs. These guarantee that struct members will be properly initialized even if they are not specified in the initializer. Note that due to a quirk in the C99 specification at least one member must be explicitly initialized even if it needs to be the default value.
Since pre-zeroed memory is no longer required, adjust memAllocInternal()/memReallocInternal() to return raw memory and update dependent functions accordingly. All instances of memset() have been removed except in debug/test code where needed.
Add memMewPtrArray() to allocate an array of pointers and automatically set all pointers to NULL.
Rename memGrowRaw() to the more logical memResize().
This macro block encapsulates the common pattern of switching to the prior (formerly called old) mem context to return results from a function.
Also rename MEM_CONTEXT_OLD() to memContextPrior(). This violates our convention of macros being in all caps but memContextPrior() will become a function very soon so this will reduce churn.
Migrate functionality from the Perl Db module to C. For now this is just enough to implement the WAL switch check.
Add the dbGet() helper function to get Db objects easily.
Create macros in harnessPq to make writing pq scripts easier by grouping commonly used functions together.
Reviewed by Cynthia Shang.
This direct interface to libpq allows simple queries to be run against PostgreSQL and supports timeouts.
Testing is performed using a shim that can use scripted responses to test all aspects of the client code. The shim will be very useful for testing backup scenarios on complex topologies.
Reviewed by Cynthia Shang.
