1. A computer-implemented method for efficiently extracting contents of container files, at least a portion of the method being performed by a computing device comprising at least one processor, the method comprising: receiving, at a first stage of a file-archiving system, an unnested container file containing a first constituent file and a second constituent file, wherein: the first constituent file is a nested container file that contains the second constituent file; and the file-archiving system is configured to perform a time-consuming file-indexing operation; enabling high file throughput at the first stage of the file-archiving system by refraining, at the first stage of the file-archiving system, from performing the time-consuming file-indexing operation; enabling a second stage of the file-archiving system to perform the time-consuming file-indexing operation on the second constituent file by creating, at the first stage of the file-archiving system, a content hierarchy for the unnested container file that comprises: metadata of the second constituent file; first hierarchical metadata that indicates that the unnested container file contains the nested container file; and second hierarchical metadata that indicates that the nested container file contains the second constituent file; using, at the second stage of the file-archiving system, the content hierarchy to locate the second constituent file within the nested container file; extracting, at the second stage of the file-archiving system, the second constituent file from the nested container file; performing, at the second stage of the file-archiving system, the time-consuming file-indexing operation on the second constituent file.
1. A computer-implemented method for efficiently extracting contents of container files, at least a portion of the method being performed by a computing device comprising at least one processor, the method comprising: receiving, at a first stage of a file-archiving system, an unnested container file containing a first constituent file and a second constituent file, wherein: the first constituent file is a nested container file that contains the second constituent file; and the file-archiving system is configured to perform a time-consuming file-indexing operation; enabling high file throughput at the first stage of the file-archiving system by refraining, at the first stage of the file-archiving system, from performing the time-consuming file-indexing operation; enabling a second stage of the file-archiving system to perform the time-consuming file-indexing operation on the second constituent file by creating, at the first stage of the file-archiving system, a content hierarchy for the unnested container file that comprises: metadata of the second constituent file; first hierarchical metadata that indicates that the unnested container file contains the nested container file; and second hierarchical metadata that indicates that the nested container file contains the second constituent file; using, at the second stage of the file-archiving system, the content hierarchy to locate the second constituent file within the nested container file; extracting, at the second stage of the file-archiving system, the second constituent file from the nested container file; performing, at the second stage of the file-archiving system, the time-consuming file-indexing operation on the second constituent file. 5. The computer-implemented method of claim 1 , wherein: the second hierarchical metadata indicates that the second constituent file is at a hierarchical level within the unnested container file; using the content hierarchy to locate the second constituent file within the nested container file comprises using the content hierarchy to locate one or more files at the hierarchical level within the unnested container file.